本科生参与发表论文目录 1. Shuangliu Zhou, Shaowu Wang,* Gaosheng Yang, Qinghai Li, Lijun Zhang, Zijian Yao, Zhangkai Zhou,

and Hai-bin Song, Synthesis, Structure, and Diverse Catalytic Activities of [Ethylenebis(indenyl)] lanthanide(III) Amides on N-H and C-H Addition to Carbodiimides and Caprolactone Polymerization, Organometallics, 2007, 26, 3755-3761

2. Hai-Yin Yu ,*, Ju-Ming He, Lan-Qin Liu , Xiao-Chun He, Jia-Shan Gu, Xian-Wen Wei, Photoinduced graft polymerization to improve antifouling characteristics of an SMBR,Journal of Membrane Science, 2007,302,235–242

3. Bin Fang, Yan Wei, Maoguo Li, Guangfeng Wang, Wei Zhang, Study on electrochemical behavior of tryptophan at a glassy carbon electrode modified with multi-walled carbon nanotubes embedded cerium hexacyanoferrate, Talanta, 2007,72,1302–1306

4. Zhousheng Yang , Guangzhi Hu, Xi Chen, Jun Zhao, Guangchao Zhao, The nano-Au self-assembled glassy carbon electrode for selective determination of epinephrine in the presence of ascorbic acid, Colloids and Surfaces B: Biointerfaces, 2007, 54, 230–235

5. Zhousheng Yang, Dapeng Zhang, Haiyan Long, Guangchao Zhao, Voltammetric Behavior of the Alizarin Red S Interaction with DNA and Damage to DNA, Electroanalysis 2007, 24, 2577 – 2582

6. Shaowu Wang , Shaoyin Wang, Shuangliu Zhou, Gaosheng Yang, Wei Luo, Nan Hu, Zhihong Zhou, Hai-Bin Song, Synthesis, characterization, and catalytic activity of divalent organolanthanide complexes with new tetrahydro-2H-pyranyl-functionlized indenyl ligands, Journal of Organometallic Chemistry, 2007,692,2099–2106

7. Guangfeng Wang, Nianjun Hu, Wen Wang, Pengcheng Li, Haochen Gu, Bin Fang, Preparation of Carbon Nanotubes/Neutral Red Composite Film Modified Electrode and Its Catalysis on Rutin, Electroanalysis, 2007,22,2329-2334

8. Lun Wang, Yan Liu, Hongqi Chen, Ani Liang, Fagong Xu, Studies on fluorenscence resonance energy transfer between CdS nanoparticles and DOCAI dyes, Chinese Chemical Letters, 2007,18,369-372

9. 傅中，付妍，胡慧，邵名望，潘世炎，X 射线光电子能谱法研究硅纳米线的能带结构，光谱学与光

谱分析，2007，9（27），1878-1881

10. 熊言林，强世苍，倪放放，校本化学实验教学研究初探，化学教育，2007，28（11），47-61

11. Baoyou Geng,* Fangming Zhan, Han Jiang, Yijun Guo and Zhoujing Xing, Egg albumin as a nanoreactor for growing single-crystalline Fe3O4 nanotubes with high yields, Chem. Commun.., 2008, 5773–5775

12. Xiaojun Zhang,* Guangfeng Wang, Aixia Gu, Yan Wei and Bin Fang, CuS nanotubes for ultrasensitive nonenzymatic glucose sensors, Chem. Commun., 2008, 5945–5947

13. Yunjun Wu, Shaowu Wang,* Xiancui Zhu, Gaosheng Yang, Yun Wei, Lijun Zhang and Hai-bin Song, Synthesis, Characterization, and Catalytic Activity of Rare Earth Metal Amides Supported by a Diamido Ligand with a CH2SiMe2 Link, Inorganic Chemistry, 2008, 47, 5503-5511

14. Baoyou Geng,* Fangming Zhan, Han Jiang, Zhoujing Xing, and Caihong Fang, Facile Production of Self-Assembly Hierarchical Dumbbell-Like CoOOH Nanostructures and Their Room-Temperature CO-Gas-Sensing Properties, Crystal Growth & Design, 2008, 8(10), 3497-3500

15. Hai-Yin Yu*, Zhao-Qi Tang, Lei Huang, Gang Cheng, Wei Li, Jin Zhou, Meng-Gang Yan, Jia-Shan Gu, Xian-Wen Wei，Surface modification of polypropylene macroporous membrane to improve its antifouling characteristics in a submerged membrane-bioreactor: H2O plasma treatment，water research, 2008, 42, 4341-4347

16. Yijun Guo, Baoyou Geng,* Li Zhang, Fangming Zhan and Jiahui You, Fabrication, Characterization, and Strong Exciton Emission of Multilayer ZnTe Nanowire Superstructures, J. Phys. Chem. C, 2008, 112, 20307–20311

17. Huaqiang Wu*, Qianyi Wang, Youzhi Yao, Cheng Qian, Xiaojun Zhang, and Xianwen Wei, Microwave-Assisted Synthesis and Photocatalytic Properties of Carbon Nanotube/Zinc Sulfide Heterostructures, J. Phys. Chem. C, 2008, 112, 16779–16783

18. Xiaojun Zhang*, Guangfeng Wang, Wei Zhang, Nianjun Hu, Huaqiang Wu and Bin Fang, Seed-Mediated Growth Method for Epitaxial Array of CuO Nanowires on Surface of Cu Nanostructures and Its Application as a Glucose Sensor, J. Phys. Chem. C, 2008, 112, 8856–8862

19. Xiaojun Zhang,* Guangfeng Wang, Xiaowang Liu, Jingjing Wu, Ming Li, Jing Gu, Huan Liu and Bin Fang, Different CuO Nanostructures: Synthesis, Characterization, and Applications for Glucose Sensors, J. Phys. Chem. C, 2008, 112, 16845–16849

20. Bin Fang,* Daolei Chen, Qiang Huang, Yan Wei, Guangfeng Wang, Fabrication and Application of a Novel Modified Electrode Based on Multiwalled Nanotubes/Cerium(III) 12-Tungstophosphoric Acid Nanocomposite, Electroanalysis, 2008,20(11), 1234 – 1240

21. Zhou-sheng Yang,* Hai-yan Long, Xiao-yan Zhang, Yong Wang, Autooxidative Activity of Chlorogenic Acid and Damage to DNA, Electroanalysis, 2008, 20(18), 1968 – 1972

22. Hongying Liu, Guangfeng Wang, Daolei Chen, Wei Zhang, Chunjing Li, Bin Fang,∗，Fabrication of polythionine/NPAu/MWNTs modified electrode for simultaneous determination of adenine and guanine in DNA，Sensors and Actuators B, 2008, 128, 414–421

23. Guangfeng Wang, Jian Meng, Hongying Liu, Shoufeng Jiao, Wei Zhang, Daolei Chen, Bin Fang∗, Determination of uric acid in the presence of ascorbic acid with hexacyanoferrate lanthanum film modified electrode, Electrochimica Acta, 2008, 53, 2837–2843

24. Yong-jia Shang*, Jian-wei Wu, Chen-li Fan, Jin-song Hu, Ben-ye Lu, Synthesis of 1,3-bis-(5-ferrocenylisoxazole-3-yl) benzene-derived palladium(II)acetate complex and its application in Mizoroki–Heck reaction in an aqueous solution, Journal of Organometallic Chemistry, 2008, 263, 2963–2966

25. Hai-Yin Yu,* Xiao-Chun He, Lan-Qin Liu, Jia-Shan Gu, Xian-Wen Wei, Surface Modification of Poly(propylene) Microporous Membrane to Improve Its Antifouling Characteristics in an SMBR: O2 Plasma Treatment, Plasma Process. Polym, 2008, 5, 84–91

26. Lun Wang∗, A.-Ni Liang, Hong-Qi Chen, Yan Liu, Bin-bin Qian, Jie Fu, Ultrasensitive determination of silver ion based on synchronous fluorescence spectroscopy with nanoparticles, analytica chimica acta,2008, 616, 170–176

27. Shao-wu Wang*, Hui-min Qian, Wei Yao, Li-jun Zhang, Shuang-liu Zhou, Gao-sheng Yang, Xian-cui Zhu, Jia-xi Fan, Yu-yu Liu, Guo-dong Chen, Hai-bin Song, Synthesis of rare earth metal complexes incorporating amido and enolate mixed ligands: Characterization and reactivity, Polyhedron, 2008, 27, 2757–2764

28. Meng-Gang Yan, Lan-Qin Liu, Zhao-Qi Tang, Lei Huang, Wei Li, Jin Zhou, Jia-Shan Gu, Xian-WenWei , Hai-Yin Yu∗, Plasma surface modification of polypropylene microfiltration membranes and fouling by BSA dispersion, Chemical Engineering Journal, 2008, 145, 218–224

29. Xiaojun Zhang, Guangfeng Wang, Haibian Wu, Di Zhang, Xiaoqing Zhang, Po Li, Huaqiang Wu, Synthesis and photocatalytic characterization of porous cuprous oxide octahedral, Materials Letters, 2008, 62, 4363–4365

30. Xiaojun Zhang, Guangfeng Wang, Aixia Gu, Huaqiang Wu, Bin Fang, Preparation of porous Cu2O octahedron and its application as L-Tyrosine sensors, Solid State Communications, 2008, 148, 525-528

31. Zhijun Feng, Shuyan Yu and Yongjia Shang∗, Novel pyridine-bis(ferrocene-isoxazole) ligand: synthesis and application to palladium-catalyzed Sonogashira cross-coupling reactions under copper- and phosphine-free conditions, Appl. Organometal. Chem. 2008, 22, 577–582

32. Xiaojun Zhang* and Huagui Zheng, Synthesis of TiO2-doped SiO2 composite films and its applications, Bull. Mater. Sci., 2008, 31(5), 787–790

33. 陈红旗，梁阿妮，许轶，王伦，CdS／PPA 纳米溶胶荧光探针同步荧光光度法测定水溶液中牛血清

白蛋白，应用化学，2008，25（12），1484-1486

34. 彭银，陈家伟，吕同杰，圣文军，纳米 ZnO 的制备及其对甲基红的光催化降解，科技资讯，2008，22，10-11

35. 王谦宜，吴华强，徐冬梅，王强，苏桂琴，侯林梅，刘流，MMA/ St 无皂阳离子乳液共聚合动力

学，高分子材料科学与工程，2008，24（10），56-59

36. 陶贵德，杨高升，张洪涛，毛浙徽，2 - [二(2 - 氨基乙基) 氨基]乙醇双核钴( III) 配合物的合成和

晶体结构，安徽师范大学学报(自然科学版)，2008，31（1），49-52

37. Yimin Hu,* Chenli Yu, Dong Ren, Qiong Hu, Lidong Zhang, and Dong Cheng, One-Step Synthesis of the Benzocyclo[penta- to octa-]isoindole Core, Angew. Chem. Int. Ed., 2009, 48, 5448 –5451

38. Yongjia Shang,* Xinwei He, Jinsong Hu, JianweiWu, Min Zhang, Shuyan Yu and Qianqian Zhang, Copper-Catalyzed Efficient Multicomponent Reaction: Synthesis of Benzoxazoline-Amidine Derivatives, Adv. Synth. Catal., 2009, 351, 2709-2713

39. Fangming Zhan, Baoyou Geng*, and Yijun Guo, Porous Co3O4 Nanosheets with Extraordinarily High Discharge Capacity for Lithium Batteries, Chem. Eur. J., 2009, 15, 6169-6174

40. Yimin Hu,* Ying Ouyang, Yuan Qu, Qiong Hu and Hao Yao, Rapid construction of five contiguous stereocenters in a multi-cascade reactionw, Chem. Commun., 2009, 4575–4577

41. Wang guangfeng, Gu aixia, Wang wen, Wei Yan, Wu jingjing, Wang guozhong, Zhang xiaojun*, Fang Bin*, Copper Oxide Nanoarray Based on the Substrate of Cu Applied for the Chemical Sensor of Hydrazine Detection, Electrochem. Comm., 2009, 11, 631-634

42. Xiaowang Liu,* Qiyan Hu, Zhen Fang, Xiaojun Zhang, and Beibei Zhang, Magnetic Chitosan Nanocomposites: A Useful Recyclable Tool for Heavy Metal Ion Removal, Langmuir, 2009, 25, 3-8

43. Xiaowang Liu,* Qiyan Hu, Zhen Fang, Qiong Wu, and Qiubo Xie, Carboxyl Enriched Monodisperse Porous Fe3O4 Nanoparticles with Extraordinary Sustained-Release Property. Langmuir, 2009, 25(13), 7244–7248

44. Lijuan Jiao,*Changjiang Yu, Jilong Li, Zhaoyun Wang, MinWu, and Erhong Hao, β-Formyl-BODIPYs from the Vilsmeier−Haack Reaction, Journal of Organic Chemistry, 2009, 74, 7525-7528

45. Jia-Shan Gu, Hai-Yin Yu*, Lei Huang, Zhao-Qi Tang, Wei Li, Jin Zhou, Meng-Gang Yan, and Xian-Wen Wei, Chain-length dependence of the antifouling characteristics of the glycopolymer-modified polypropylene membrane in an SMBR, Journal of Membrane Science, 2009, 326, 145-152

46. Hai-Yin Yu*, Wei Li, Jin Zhou, Jia-Shan Gu, Lei Huang, Zhao-Qi Tang, and Xian-Wen Wei, Thermo- and pH-responsive polypropylene microporous membrane prepared by the photoinduced RAFT-mediated graft copolymerization. Journal of Membrane Science, 2009, 343, 82-89

47. Yinling Wang*, Dandan Zhang, Weiwei Zhang, Feng Gao, Lun Wang, A facile strategy for nonenzymatic glucose detection, Anal. Biochemi., 2009, 385, 184-186

48. Fang Bin *, Zhang Cuihong, Zhang Wei, Wang Guangfeng, A novel hydrazine electrochemical sensor based on a carbon nanotube-wired ZnO nanoflower-modified electrode, Electrochimica Acta., 2009, 55, 178–182

49. Lijuan Jiao,* Jilong Li, Shengzhou Zhang, Chao Wei, Erhong Hao and M. Graca H.Vicente, A selective fluorescent sensor for imaging Cu2+ in living cells, New Journal of Chemistry, 2009, 33, 1888-1893

50. Zhang Wei, Wang Lili, Zhang Na, Wang Guangfeng, Fang Bin*, Functionalization of Single-Walled Carbon Nanotubes with Cubic Prussian Blue and Its Application for Amperometric Sensing, Electroanalysis, 2009, 21(21), 2325-2330

51. Bin Fang*, Shen Rongxing, Zhang Cuihong, Yuan Huali, Yao Li, Wang Guangfeng, Electrochemical preparation and characterization of neodymium hexacyanoferrate and its application, Electroanalysis, 2009,21(24),2680-2684

52. Hongling Qi, Wu Zhang*, Xiang Wang, Hong Li, Jie Chen, Kaishan Peng, Mingwang Shao, Heck reaction catalyzed by flower-like cobalt nanostructures, Catalysis Communications, 2009, 10(8), 1178–1183

53. Xiaowang Liu, Qiyan Hu, QiongWu,Wei Zhang, Zhen Fang, Qiubo Xie, Aligned ZnO nanorods: A useful film to fabricate amperometric glucose biosensor, Colloids and Surfaces B: Biointerfaces, 2009, 74, 154–158

54. Zhao-Qi Tang, Wei Li, Jin Zhou, Hai-Yin Yu*, Lei Huang, Meng-Gang Yan, Jia-Shan Gu, and Xian-Wen Wei, Antifouling characteristics of sugar immobilized polypropylene microporous membrane by activated sludge and bovine serum albumin, Separation and Purification Technology, 2009, 64, 332-336

55. Fang Bin *, Zhang Na, Zhang Wei, Gu Aixia, Wang Guangfeng, A Novel Hydrogen Peroxide Sensor Based on Multi-walled Carbon Nanotubes/Poly(Pyrocatechol Violet) Modified Glassy Carbon Electrode, Journal of Applied Polymer Science. 2009, 112, 3488–3493

56. Fang Bin *, Shen Rongxing, Zhang Wei, Wang Guangfeng, Zhang Cuihong, Electrocatalytic oxidation of hydrazine at chromium hexacyanoferrate/single-walled carbon nanotubes modified glassy carbon Electrode, Microchim.Acta. 2009,165, 231-236

57. Fang Bin *, Gu Aixia, Wang Guangfeng, Li Bo, Zhang cuihong, Fang Yongyi, Zhang Xiaojun, Synthesis hexagonal ß-Ni(OH)2 nanosheets for use in electrochemistry sensors, Microchim.Acta. 2009,167, 47–52

58. Zhang Wei, Wang Guangfeng, Zhang Na, Zhang Cuihong, Fang Bin*, Preparation of Carbon Nanoparticles from Candle Soot, Chem. Lett., 2009, 38, 28-29

59. Fangming Zhan, Baoyou Geng*, Yijun Guo, Lei Wang, One-step synthesis of hierarchical carnation-like NiS superstructures via a surfactant-free aqueous solution route, Journal of Alloys and Compounds, 2009, 482, 1–5

60. Shifeng Li*, Xiangzi Li, Yanqi Zhang, Fei Huang, Fenfen Wang, Xianwen Wei*, Enhanced chemiluminescence of the luminol–KIO4 system by ZnS nanoparticles, Microchimica. Acta, 2009, 167(1-2), 103~108

61. Wang guangfeng, Liu min, Wang guozhong, Hu hao, Li jinlong, Liu kan, Zhang xiaojun, Fang bin*, Preparation of CuO-Nanoparticle-ModifiedElectrode and Its Application in theDetermination of Rutin, Anal. Lett., 2009, 42, 1084–1093

62. Wang guangfeng, Wang wen, Wu jianfeng, Liu hongying, Jiao shoufeng, Fang bin*, Self-assembly of a silver nanoparticles modified electrode and its electrocatalysis on neutral red, Microchim Acta, 2009, 164, 149–155

63. Zhang xiaojun*, Gu aixia, Wang guangfeng, Wang wen, Wu huaqiang, Fang Bin, Seed-mediated Preparation of CuO Nanoflowers and their Application as Hydrazine Sensor, Chem. Lett., 2009, 38, 466-467

64. Zhang xiaojun*, Wang guangfeng, Wang qi, Zhao lijun, Wang man, Fang Bin, Cupreous Oxide Nanobelts as Detector for Determination of L-Tyrosine, Mat. Sci. Eng. B, 2009, 156, 6-9

65. Yongjia Shang*, Dongmei Wang,and Jing Wu, Novel Sc(OTf)3/3-HQD Catalyst for Morita–Baylis–Hillman Reaction, Synthetic Communications, 2009, 39, 1035-1045

66. Xiao-Chun He, Lan-Qin Liu, Zhao-Qi Tang, Meng-Gang Yan, Jia-Shan Gu, Xian-Wen Wei, and Hai-Yin Yu*, Reducing protein fouling of polypropylene microporous membrane by CO2 plasma surface modification. Desalination, 2009, 44, 80-89

67. Hua-QiangWu, QiangWang, You-Zhi Yao, Cheng Qian, Pei-Pei Cao, Xiao-Jun Zhang, Xian-WenWei, Microwave-assisted synthesis and highly photocatalytic activity of MWCNT/ZnSe heterostructures, Materials Chemistry and Physics, 2009, 113, 539–543

68. 彭银，熊言林，张敏，化学实验置设计与教学思考，教学仪器与实验，2009，25（1），11-15.

69. 熊言林，马善恒，蒋业健，郑楠，周红丽，王华，田玮，2008 年加拿大国家化学周实验活动简介

与启示，化学教育，2009，30（5），78-80

70. 熊言林，张敏，氮元素正价变化组合实验探究，化学教育，2009，30（5），51-53

71. Qian Wang, Baoyou Geng*, Shaozhen Wang, Yixing Ye and Bo Tao, Modified Kirkendall effect for fabrication of magnetic nanotubes, Chem. Commun., 2010, 46, 1899-1901

72. Yimin Hu*, Yuan Qu, Fenghua Wu, Jinghan Gui, Yun Wei, Qiong Hu and Shaowu Wang*, Tuned C-H Functionalization to Construct the Skeleton of Aza-Podophyllotoxin/Aza-Conidendrin via Domino Cyclization, Chem.-Asian J.,2010, 5, 309-314

73. Haiyan Wang*, Fuqiang Zhang, Zhian Tan, Qiongfang Chen, Lun Wang, Greatly enhanced electrochemiluminescence of CdS nanocrystals upon heating in the presence of ammonia, Electrochem. Commun., 2010, 12(5), 650–652

74. Lijuan Jiao,* Changjiang Yu, Mingming Liu, Yangchun Wu, Kebing Cong, Ting Meng, Yuqing Wang, and Erhong Hao, Synthesis and Functionalization of Asymmetrical Benzo-Fused BODIPY Dyes, J. Org. Chem., 2010, 75(17), 6035–6038

75. Long Kuai, Baoyou Geng,* Xiaoting Chen, Yanyan Zhao, and Yinchan Luo, Facile Subsequently Light-Induced Route to Highly Efficient and Stable Sunlight-Driven Ag-AgBr Plasmonic Photocatalyst, Langmuir, 2010, 26(24), 18723-18727

76. Lijuan Jiao,* Changjiang Yu, Timsy Uppal, Mingming Liu, Yan Li, Yunyou Zhou, Erhong Hao, Xiaoke Hu and M. Graça H. Vicente,* Long Wavelength Red Fluorescent Dyes from 3,5-Diiodo-BODIPYs, Org. Biomol. Chem., 2010, 8(11), 2517–2519

77. Cuihong Zhang, Guangfeng Wang,Yulan Ji, Min Liu, Yuehua Feng, Zhidan Zhang, Bin Fang*, A hydroxylamine electrochemical sensor based on electrodeposition of porous ZnO nanofilms onto carbon nanotubes films modified electrode, Electrochim. Acta, 2010, 55 (8): 2835-2840

78. Wang GF, Zhang CH, He XP, Li ZJ, Zhang XJ, Wang L*, Fang B, Detection of hydrazine based on Nano-Au deposited on Porous-TiO2 film, Electrochim. Acta, 2010, 55, 7204-7210

79. Gu AX, Wang GF, Gu J, Zhang XJ*, Fang B*, An unusual H2O2 electrochemical sensor based on Ni(OH)2 nanoplates grown on Cu substrate, Electrochim. Acta, 2010, 55(24), 7182-7187

80. Yongjia Shang, * Cuie Wang, Xinwei He, Kai Ju, Min Zhang, Shuyan Yu, Jiaping Wu, DMAP-catalyzed cascade reaction: one-pot synthesis of benzofurans in water, Tetrahedron, 2010, 66, 9629-9633

81. H.-Y. Yu*, J. Zhou, J.-S. Gu*, and S. Yang, Manipulating membrane permeability and protein rejection of UV-modified polypropylene macroporous membrane. J. Membrane Sci., 2010, 364,203-210

82. Baoyou Geng*, Jun Liu, Chunhua Wang, Multi-layer ZnO architectures: Polymer induced synthesis and their application as gas sensors, Sensor. Actuat. B, 2010, 150, 742-748

83. Cuihong Zhang, Guangfeng Wang,Yulan Ji, Min Liu, Yuehua Feng, Zhidan Zhang, Bin Fang*, Enhancement in analytical hydrazine based on gold nanoparticles deposited on ZnO-MWCNTs films, Sensor. Actuat. B, 2010, 150 (1): 247-253

84. Yan Sang, Baoyou Geng* and Jie Yang, Fabrication and growth mechanism of three-dimensional spherical TiO2 architectures consisting of TiO2 nanorods with {110} exposed facets, Nanoscale, 2010, 2, 2109-2113

85. Na Zhang, Guangfeng Wang,Aixia Gu,Yuehua Feng, Bin Fang*, Fabrication of prussian blue/multi-walled carbon nanotubes modified electrode for electrochemical sensing of hydroxylamine, Microchimica Acta, 2010, 168 (1-2): 129-134

86. Yimin Hu,* Xiangang Lin, Tao Zhu, Jing Wan, Yongjie Sun, Quansheng Zhao, Tao Yu, A Convenient Domino Synthesis of 4,9-Diphenyl-2,3-dihydro-1H-benzo[f]isoindole Derivatives, Synthesis, 2010, 42, 3467-3473

87. Lijuan Jiao,* Ting Meng, Yongmin Chen, Min Zhang, Xiaolong Wang and Erhong Hao,* Triazolyl-linked 8-Hydroxyquinoline Dimer as a Selective Turn-on Fluorosensor for Cd2+, Chemistry Letters, 2010, 39(8), 803-805

88. Shifeng Li, Shanjun Tao, Fenfen Wang, Jianguo Hong and Xianwen Wei*, Chemiluminescence reactions of luminol system catalyzed by nanoparticles of a gold/silver alloy, Microchimica Acta, 2010,169(1-2), 73-78

89. Xiaowang Liu, Qiyan Hu, Zhen Fang, Xuan Gao, Tao Jiang, Peifa Wei, Synthesis and characterization of nickel chains assembled by microspheres via a polymer-free hydrothermal method, J.Cry.Grow., 2010, 312，863–868

90. Yinling Wang, Lin Liu, Dandan Zhang, Shudong Xu, Maoguo Li*, A New Strategy for Immobilization of Electroactive Species on the Surface of Solid Electrode, Electrocatalysis, 2010, 1, 230-234

91. Yuzhong Zhang*, Jie Wang, Minglu Xu, A sensitive DNA biosensor fabricated with gold nanoparticles/ploy (p-aminobenzoic acid)/carbon nanotubes modified electrode, Colloids and Surfaces B: Biointerfaces, 2010, 75: 179–185

92. Ming Cao, MeiGui Liu, Chun Cao, YunSheng Xia, LingJun Bao, YingQiong Jin, Song Yang, ChangQing Zhu*, A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes, Spectrochimica Acta Part A, 2010, 75(3), 1043-1046

93. 焦莉娟*， 李继龙，丁道俊，陈颖，张勉,一种新型 α-甲氧基甲基吡咯的合成,应用化学，2010，27(1)：48-52

94. 肖艳玲，冯跃华，卢黄，张国平，基体改进剂在石墨炉原子吸收法测定食品中铅的应用，安徽师范

大学学报，2010，33，48-51

95. 张武，彭凯山，陈洁，曾庆龙，岳云，王正华，梭形碱式碳酸镨及氧化镨的合成，安徽师范大学学

报，2010，33，43-47

96. Long Kuai, Shaozhen Wang and Baoyou Geng*, Gold–platinum yolk–shell structure: a facile galvanic displacement synthesis and highly active electrocatalytic properties for methanol oxidation with super CO-tolerance, Chem. Commun. 2011, 47, 6093–6095

97. Han Jiang, Baoyou Geng*, Long Kuai and Shaozhen Wang, Simultaneous reduction-etching route to Pt/ZnSnO3 hollow polyhedral architectures for methanol electrooxidation in alkaline media with superior performance, Chem. Commun. 2011, 47, 2447–2449

98. Long Kuai, Baoyou Geng,* Shaozhen Wang, Yanyan Zhao, Yinchan Luo, and Han Jiang, Silver and Gold Icosahedra: One-Pot Water-Based Synthesis and Their Superior Performance in the Electrocatalysis for Oxygen Reduction Reactions in Alkaline Media, Chem. Eur. J. 2011, 17, 3482–3489

99. Yan Wei, Ling-Tao Kong, Ran Yang, Lun Wang*, Jin-Huai Liu, and Xing-Jiu Huang, Single-Walled Carbon Nanotube/Pyrenecyclodextrin Nanohybrids for Ultrahighly Sensitive and Selective Detection of p-Nitrophenol, Langmuir 2011, 27, 10295–10301

100. Xuelian Li, Wenjing Wei, Shaozhen Wang, Long Kuai and Baoyou Geng*, Single-crystalline α-Fe2O3 oblique nanoparallelepipeds: High-yield synthesis, growth mechanism and structure enhanced gas-sensing properties, Nanoscale 2011, 3, 718–724

101. Gaosheng Yang,* Yue Shen, Kui Li, Yongxian Sun, and Yuanyuan Hua,AlCl3-Promoted Highly Regio- and Diastereoselective [3 + 2] Cycloadditions of Activated Cyclopropanes and Aromatic Aldehydes: Construction of 2,5-Diaryl-3,3,4-trisubstituted Tetrahydrofurans, J. Org. Chem., 2011, 76, 229–233

102. Jiao, L J.; Pang, W.; Zhou, J.; Wei, Y.; Mu, X.; Hao, E. Regioselective Stepwise Bromination of Boron Dipyrromethene (BODIPY) Dyes. J. Org. Chem. 2011, 76, 9988-9976

103. Feng Gao*, Peng Cui, Xiaoxiao Chen, Qingqing Ye, Maoguo Li, Lun Wang. A DNA hybridization detection based on fluorescence resonance energy transfer between dye-doped core-shell silica nanoparticles and gold nanoparticles. Analyst, 2011, 136, 3973–3980

104. Xiaojun Zhang, Aixia Gu, Guangfeng Wang, Yan Huang, Huiqing Ji, Bin Fang, Porous Cu–NiO modified glass carbon electrode enhanced nonenzymatic glucose electrochemical sensors, Analyst, 2011, 136, 5175–5180

105. Yan Wei, Ran Yang, Xiang-Zi Li, Lun Wang* and Xing-Jiu Huang* Layer-by-layer assembly and electrochemical study of a 4-aminothiophenol and ytterbium(III) trifluoromethanesulfonate hydrate film on a gold electrode, Analyst, 2011, 136, 3997–4002

106. Yu, C. J.; Jiao, L. J.; Yin, H.; Zhou, Z. Y.; Pang, W. D.; Wu, Y. C.; Wang, Z. Y.; Yang, G. S.; Hao, E. H. α-/β-Formylated Boron–Dipyrrin (BODIPY) Dyes: Regioselective Syntheses and Photophysical Properties. Eur. J. Org. Chem. 2011, 28, 5460–5468

107. Kai Mi, Yonghong Ni*, Yanwei Xu, Jianming Hong, A simple mixed solvothermal route for LaPO4 nanorods: synthesis, characterization, affecting factors and PL properties of LaPO4:Ce3+. J. Colloid Interface Sci., 2011, 256, 490-495

108. Yan Wei, Ran Yang, Yong-Xing Zhang, Lun Wang,* Jin-Huai Liu* and Xing-Jiu Huang*,High adsorptive c-AlOOH(boehmite)@SiO2/Fe3O4 porous magnetic microspheres for detection of toxic metal ions in drinking water, Chem. Commun., 2011, 47, 11062–11064

109. Feng Gao,* Xinying Guo, Jun Yin, Dan Zhao, Maoguo Li and Lun Wang. Electrocatalytic activity of carbon spheres towards NADH oxidation at low overpotential and its applications in biosensors and biofuel cells. RSC Advances, 2011, 1, 1301–1309

110. Feng Gao,* Qingqing Ye, Peng Cui, Xiaoxiao Chen, Maoguo Li and Lun Wang. Selective ‘‘turn-on’’ fluorescent sensing for biothiols based on fluorescenceresonance energy transfer between acridine orange and gold nanoparticles. Anal. Methods, 2011, 3, 1180-1185

111. Ting Ge, Long Kuai, Baoyou Geng*, Solution-phase chemical route to branched single-crystalline CdS nanoarchitectures and their field emission property, J. Alloys Compd. 2011, 509, L353– L358

112. Erhong Hao, Ting Meng, Min Zhang, Weidong Pang, Yunyou Zhou, and Lijuan Jiao. Solvent Dependent Fluorescent Properties of a 1,2,3-Triazole Linked 8-Hydroxyquinoline Chemosensor: Tunable Detection from Zinc(II) to Iron(III) in the CH3CN/H2O System. J. Phys. Chem. A 2011, 115(29), 8234-8241

113. Xie Meihua, Feng Chengyou, Zhang Jitan, Liu Changqing, Fang Kuang, Shu Guanying, Zuo Wansheng “CuI-Catalyzed tandem carbomagnesiation/carbonyl addition of Grignard reagents with acetylenic ketones: convenient access to tetrasubstituted allylic alcohols” J. Organomet. Chem., 2011, 696(21), 3397-3401

114. Huaqiang Wu, Peipei Cao, Wenting Li, Na Ni, Lulu Zhu and Xiaojun Zhang, Microwave-assisted synthesis and magnetic properties of size-controlled CoNi/MWCNT nanocomposites, Journal of Alloys and Compounds,2011,509（4）:1261-1265

115. 陈守梅，顾家山，陈欣，王曼，百年诺贝尔化学奖的历史回顾与启示，化学教育，2011,32（5）：

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116. 熊言林，李晓龙，金海莲，汪清，陶敏，蜡烛燃烧产物二氧化碳非常规灭火原因的实验探究.化学

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117. 段中东，熊言林∗，SPSS17.0 在制备氢氧化亚铁研究中的应用，化学教育，2011，32（3）：57-62

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120. Long Kuai, Xue Yu, Shaozhen Wang, Yan Sang, and Baoyou Geng*, Au−Pd Alloy and Core−Shell Nanostructures: One-Pot Coreduction Preparation, Formation Mechanism, and Electrochemical Properties, Langmuir 2012, 28, 7168−7173

121. Guangfeng Wang,* Xiuping He, Baojuan Wang, Xiaojun Zhang and Lun Wang*, Electrochemical amplified detection of Hg2+ based on the supersandwich DNA structure†, Analyst, DOI: 10.1039/c2an35048c

122. Yanyan Zhao, Long Kuai and Baoyou Geng*, Low-cost and highly efficient composite visible light-driven Ag–AgBr/c-Al2O3 plasmonic photocatalyst for degrading organic pollutants, Catal. Sci. Technol., 2012, 2, 1269–1274

Synthesis, Structure, and Diverse Catalytic Activities of[Ethylenebis(indenyl)]lanthanide(III) Amides on N-H and C-HAddition to Carbodiimides and ε-Caprolactone Polymerization

Shuangliu Zhou,† Shaowu Wang,*,†,‡ Gaosheng Yang,† Qinghai Li,† Lijun Zhang,†Zijian Yao,† Zhangkai Zhou,† and Hai-bin Song§

Anhui Key Laboratory of Functional Molecular Solids, Institute of Organic Chemistry, College ofChemistry and Materials Science, Anhui Normal UniVersity, Wuhu, Anhui 241000, People’s Republic of

China, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences, Shanghai 200032, People’s Republic of China, and State Key Laboratory of

Elemento-Organic Chemistry, Nankai UniVersity, Tianjin 300071, People’s Republic of China

ReceiVed March 11, 2007

The simple silylamine elimination reaction of ethylenebis(indene) with the lanthanide amides [(Me3-Si)2N]3Ln(μ-Cl)Li(THF)3 produced the [ethylenebis(η5-indenyl)][bis(trimethylsilyl)amido]lanthanide(III)complexes (EBI)LnN(TMS)2 (Ln ) Y (1), Sm (2), Yb (3)), which exhibited diverse catalytic activitieson the addition of the N-H bond of amines and the C-H bond of terminal alkynes to the carbodiimidesand on the ring-opening polymerization of ε-caprolactone as well. The new complexes 1 and 2 werefully characterized by spectroscopic methods, elemental analyses, and X-ray crystallographic analyses.This work offers a straightforward, highly atom efficient route for the syntheses of substituted guanidinesand propiolamidines, and it represents the first application of readily accessible lanthanocene amides tothese reactions.

Introduction

Many natural products and synthetic pharmaceuticals containguanidine functional groups, which often play an essential rolein their biological activity.1 Guanidines have received consider-able attention as ancillary ligands in the preparation of a varietyof metal complexes, including those of early-transition-metalsand lanthanide complexes.2 Typical methods for the preparationof substituted guanidines employ the reaction of an amine withelectrophilic guanylating reagent3 or functionalization of a

preexisting guanidine core.4 On the other hand, the addition ofthe N-H bonds of the amines to carbodiimides (RNdCdNR)provides a direct and atom-efficient route to the guanidines;however, primary aliphatic amines are the only examples thatcan undergo direct guanylation with carbodiimides to yield thecorresponding N,N′,N′′-trialkylguanidines under rather forcingconditions.5 Aromatic amines or secondary amines do not reactwith carbodiimides under the same or harsher conditions. Onlya few works on the catalytic intermolecular hydroamination ofthe carbodiimides have provided direct methods for the con-struction of the CN-rich functionalized guanidines; for example,it has been reported that the lithium bis(trimethylsilyl) amideLiN(TMS)2 can catalyze intermolecular hydroamination reactionof the aromatic amines and carbodiimides,6 the half-sandwichyttrium alkyl complex {Me2Si(C5Me4)(NR)}Ln(CH2SiMe3)-(THF)n can catalyze the guanylation of aromatic amines andsecondary amines,7 and titanacarboranyl complexes or transition-metal-imido complexes can catalyze the guanylation of aro-matic and secondary amines.8 However, the synthesis ofguanidines and propiolamidines using lanthanocene amidocomplexes as catalysts still remains to be examined.

Propiolamidines (RNdC(CtCR′)(NHR)), which contain aconjugated C-C triple bond, could hardly be obtained because

† Anhui Normal University.‡ Shanghai Institute of Organic Chemistry.§ Nankai University.(1) (a) The Pharmacological Basis of Therapeutics, 7th ed.; Gilman, A.

G., Goodman, L. S., Rall, T. W., Murad, F., Eds.; Pergamon Press: NewYork, 1990; p 899. (b) Hu, L. Y.; Guo, J.; Magar, S. S.; Fischer, J. B.;Burke-Howie, K. J.; Durant, G. J. J. Med. Chem. 1997, 40, 4281-4289.(C) Manimala, J. C.; Anslyn, E. V. Eur. J. Org. Chem. 2002, 3909.

(2) (a) Tin, M. K. T.; Yap, G. P. A.; Richeson, D. S. Inorg. Chem. 1998,37, 6728-6730. (b) Rowley, C. N.; DiLabio, G. A.; Barry, S. T. Inorg.Chem. 2005, 44, 1983-1991. (c) Foley, S. R.; Zhou, Y.; Yap, G. P. A.;Richeson, D. S. Inorg. Chem. 2000, 39, 924-929. (d) Dagorne, S.; Guzei,I. A.; Coles, M. P.; Jordan, R. F. J. Am. Chem. Soc. 2000, 122, 274-289.(e) Kennedy, A. R.; Mulvey, R. E.; Bowlings, R. B. J. Am. Chem. Soc.1998, 120, 7816-7824. (f) Keaton, R. J.; Jayaratne, K. C.; Henningsen, D.A.; Koterwas, L. A.; Sita, L. R. J. Am. Chem. Soc. 2001, 123, 6197-6198.(g) Kondo, H.; Yamaguchi, Y.; Nagashima, H. J. Am. Chem. Soc. 2001,123, 500-501. (h) Averbuj, C.; Eisen, M. S. J. Am. Chem. Soc. 1999, 121,8755-8759. (i) Bambirra, S.; Bouwkamp, M. W.; Meetsma, A.; Hessen,B. J. Am. Chem. Soc. 2004, 126, 9182-9183. (j) Deng, M.; Yao, Y.; Zhang,Y.; Shen, Q. Chem. Commun. 2004, 2742-2743. (k) Zhang, J.; Ruan, R.;Shao, Z.; Cai, R.; Weng, L.; Zhou, X. Organometallics 2002, 21, 1420-1424.

(3) (a) Li, J.; Zhang, Z.; Fan, E. Tetrahedron Lett. 2004, 45, 1267. (b)Convers, E.; Tye, H.; Whittaker, M. Tetrahedron Lett. 2004, 45, 3401. (c)Yu, Y.; Ostresh, J. M.; Houghten, R. A. J. Org. Chem. 2002, 67, 3138. (d)Wu, Y. Q.; Hamilton, S. K.; Wilkinson, D. E.; Hamilton, G. S. J. Org.Chem. 2002, 67, 7553. (e) Tamaki, M.; Han, G.; Hruby, V. J. J. Org. Chem.2001, 66, 1038. (f) Musiol, H. J.; Moroder, L. Org. Lett. 2001, 3, 3859. (g)Kent, D. R.; Cody, W. L.; Doherty, A. M. Tetrahedron Lett. 1996, 37,8711.

(4) (a) Evindar, G.; Batey, R. A. Org. Lett. 2003, 5, 133. (b) Powell, D.A.; Ramsden, P. D.; Batey, R. A. J. Org. Chem. 2003, 68, 2300. (c) Ghosh,A. K.; Hol, W. G. J.; Fan, E. J. Org. Chem. 2001, 66, 2161.

(5) Thomas, E. W.; Nishizawa, E. E.; Zimmermann, D. C.; Williams,D. J. J. Med. Chem. 1989, 32, 228-236.

(6) Ong, T.-G.; O’Brien, J. S.; Korobkov, I.; Richeson, D. S. Organo-metallics 2006, 25, 4728-4730.

(7) (a) Zhang, W.-X.; Nishiura, M.; Hou, Z. Synlett 2006, 8, 1213-1216. (b) Zhang, W.-X.; Nishiura, M.; Hou, Z. Chem. Eur. J. 2007, 13,4037-4051.

(8) (a) Shen, H.; Chan, H.-S.; Xie. Z. Organometallics 2006, 25, 5515-5517. (b) Ong, T.-G.; Yap, G. P. A.; Richeson, D. S. J. Am. Chem. Soc.2003, 125, 8100-8101. (c) Montilla, F.; Pastor, A.; Galindo, A. J.Organomet. Chem. 2004, 689, 993-996.

3755Organometallics 2007, 26, 3755-3761

10.1021/om070234s CCC: $37.00 © 2007 American Chemical SocietyPublication on Web 06/14/2007

Journal of Membrane Science 302 (2007) 235–242

Photoinduced graft polymerization to improve antifoulingcharacteristics of an SMBR

Hai-Yin Yu a,∗, Ju-Ming He b, Lan-Qin Liu a, Xiao-Chun He c, Jia-Shan Gu a, Xian-Wen Wei a

a College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, Chinab DuPont Huajia Chemical Co. Ltd., Huangshan 245061, China

c Nantong Vocational College, Nantong 226007, China

Received 18 April 2007; received in revised form 23 June 2007; accepted 26 June 2007Available online 3 July 2007

Abstract

Hydrophobic polypropylene hollow fiber microporous membranes (PPHFMMs) were surface-modified by photoinduced graft polymerizationof 2-aminoethyl methacrylate (AEMA), which were characterized by attenuated total reflection—Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM). Water contact angle was measuredby the sessile drop method. The results of FT-IR/ATR and XPS clearly indicated that AEMA was grafted on the membrane surface. The watercontact angle on the modified membrane was 50.3◦ lower than that of the unmodified membrane. The antifouling characteristics in a submergedmembrane bioreactor (SMBR) were investigated. After continuous operation in the SMBR for about 65 h, reduction from pure water flux was3.03% lower, flux recovery after water and caustic cleaning were 28.01 and 48.95% higher for the AEMA grafted PPHFMM with a grafting degreeof 5.67 wt.% than those of the unmodified membrane, flux ratio after fouling was 1.78 times for the modified membrane with a grafting degree of7.30 wt.% of the unmodified one.© 2007 Elsevier B.V. All rights reserved.

Keywords: Surface modification; Polypropylene microporous membrane; Photoinduced graft polymerization; Aminoethyl methacrylate; Submerged membranebioreactor; Antifouling characteristics

1. Introduction

In many areas of membrane separation process, the surfacechemical and physical properties, including molecular weightcut off (MWCO) (or pore size) and surface roughness, especiallythe surface wettability and surface charge, play dominant rolesin determining the separation characteristics. Polymeric mem-branes exhibit high potentials for comprehensive applicationsdue to the higher chemical and thermal stabilities and low cost.However, the low energy surface or relatively high hydropho-bicity probably leads to membrane fouling [1,2]. It is widelyaccepted that the antifouling characteristics for the hydrophilicmembrane are better than those of the hydrophobic one. As aresult, surface modification of membranes from hydrophobicityto hydrophilicity is thought to be as important to the mem-brane industry as membrane material and process development.

∗ Corresponding author. Tel.: +86 553 5991165; fax: +86 553 3869303.E-mail address: yhy456@mail.ahnu.edu.cn (H.-Y. Yu).

Polypropylene is one of the most important polymers widelyused in various fields, while as membrane materials the existinginconveniences make it requisite to some surface modification.

Surface modification of membranes is an attractive approachto change the surface properties of the membrane. Differentmethods such as UV irradiation [3–7], plasma treatment [8–10],gamma irradiation and ion beam irradiation [11,12], and chem-ical reaction have been employed to modify the membranesurface. Among the various surface-modification techniques,UV-assisted graft polymerization is a desirable method for thefollowing reasons. First, photoinduced graft polymerization isinitiated without prior modification of a surface. Second, a highconcentration of active species is produced locally at the inter-face between the substrate polymer and the monomer solution.Third, the procedure is relatively simple, energy-efficient, andcost-effective.

While there are many reports of surface modification,few results have addressed the application to the submergedmembrane bioreactor (SMBR) process [13–16]. Membranebioreactor process has been deemed to be a promising

0376-7388/$ – see front matter © 2007 Elsevier B.V. All rights reserved.doi:10.1016/j.memsci.2007.06.061

Talanta 72 (2007) 1302–1306

Study on electrochemical behavior of tryptophan at a glassy carbonelectrode modified with multi-walled carbon nanotubes

embedded cerium hexacyanoferrate

Bin Fang a,c,∗, Yan Wei a,b,c, Maoguo Li a,c, Guangfeng Wang a,c, Wei Zhang a,c

a College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, Chinab Department of Chemistry, Wannan Medical College, Wuhu 241000, PR Chinac Anhui Key Laboratory of Functional Molecular Solids, Wuhu 241000, China

Received 20 October 2006; received in revised form 3 January 2007; accepted 14 January 2007Available online 20 January 2007

Abstract

Electrochemical behavior of cerium hexacyanoferrate (CeHCF) incorporated on multi-walled carbon nanotubes (MWNTs) modified GC elec-trode is investigated by scanning electron microscopy (SEM) and electrochemical techniques. The CeHCF/MWNT/GC electrode showed potentelectrocatalytic activity toward the electrochemical oxidation of tryptophan in phosphate buffer solution (pH 7.0) with a diminution of the over-potential of 240 mV. The anodic peak currents increased linearly with the concentration of tryptophan in the range of 2.0 × 10−7 to 1.0 × 10−4 Mwith a detection limit of 2.0 × 10−8 M (at a S/N = 3). And the determination of tryptophan in pharmaceutical samples was satisfactory.© 2007 Elsevier B.V. All rights reserved.

Keywords: Cerium hexacyanoferrate; Multi-walled carbon nanotubes; Modified electrode; Tryptophan; Electroanalysis

1. Introduction

Tryptophan (Trp) is an amino acid essential to humans. Itis a vital constituent of proteins and indispensable in humannutrition for establishing and maintaining a positive nitrogenbalance. These compounds are sometimes added to dietary, foodproducts, pharmaceutical formulas due to the scarcely presencein vegetables. Therefore simple, sensitive and less expensivedetection of Trp is of great interest. The methods based on elec-troanalysis of Trp have been many reported [1–8]. It is wellknown that the direct electrochemical oxidation of Trp at a bareelectrode takes place at high overpotential. The reported overpo-tential at pH 7.0 is 0.800 V at glassy carbon (GC) electrode [3].Many efforts have been devoted to the goal of finding the newmaterial (mediators) for electrode modification that will reducethe overpotential of the oxidation of Trp [1–8]. Recently, Lin etal. [3] have reported the electrocatalytic oxidation of Trp at a

∗ Corresponding author at: College of Chemistry and Materials Science, AnhuiNormal University, Wuhu 241000, China.

E-mail address: binfang 47@yahoo.com.cn (B. Fang).

GC electrode modified with butyrylcholine with decreasing of131 mV in overpotential.

Cerium compound possesses many attractive propertieswhich makes it highly promising for a wide range of appli-cations such as solid electrolytes in solid oxide fuel cells [9],automotive three-way catalysts, ultraviolet absorbers [10,11],and oxygen sensors [12]. It is also used as a catalyst for large-scale fluid cracking in refineries and dehydrogenation of ethylbenzene to styrene [13]. Studies on metal hexacyanoferrate havebeen documented on transition metal compounds [14–21]. Acerium hexacyanoferrate (CeHCF) modified glassy carbon elec-trode was prepared by electrochemical method in this paper.However, this modified electrode is instable. As we all know,stability of modified electrode is highly desirable in order toexpand its use in numerous practical applications. Electrodesbased on carbon nanotubes are an attractive research area now[22–25]. Carbon nanotube is a kind of inorganic material with anano-structure, which is promising as immobilization substancebecause of its significant mechanical strength, high surface area,excellent electrical conductivity and good chemical stability[26].

0039-9140/$ – see front matter © 2007 Elsevier B.V. All rights reserved.doi:10.1016/j.talanta.2007.01.039

Egg albumin as a nanoreactor for growing single-crystalline Fe3O4

nanotubes with high yieldsw

Baoyou Geng,* Fangming Zhan, Han Jiang, Yijun Guo and Zhoujing Xing

Received (in Cambridge, UK) 29th July 2008, Accepted 3rd September 2008

First published as an Advance Article on the web 1st October 2008

DOI: 10.1039/b813071j

Single-crystalline Fe3O4 nanotubes have been synthesized suc-

cessfully by using egg albumin as a nanoreactor; these three-

dimensional material nanotubes are formed through a rolling

mechanism under mild biological conditions.

In recent years considerable attention has been focused on

one-dimensional (1D) nanostructured materials owing to their

unique physical properties and potential applications. In

particular, tubular-structured materials have shown unique

chemical and physical properties because of their having outer

as well as inner surfaces and a nanometre thick ‘‘wall’’. Much

effort has been devoted to the controllable synthesis of in-

organic nanotubes since the discovery of carbon nanotubes in

1991.1 The synthesis of a number of tubular materials from

two-dimensional layered precursors at elevated temperatures,

based on a ‘‘rolling-up’’ mechanism, has been reported,2 such

as those made from BN, V2O5, WS2, and NiCl2. Nanotubes

made from other materials,3 such as Si, ZnS, Eu2O3, and GaN,

which do not possess 2D layered structures, have also been

prepared by employing various hard templates. However,

except for a few examples,3,4 the template-assisted method

has been proved to be unsuitable for the formation of single-

crystalline nanotubes. A mild solution strategy has been used

to obtain single-crystalline hexagonal prismatic Te nano-

tubes,5 but it is difficult to extend this method to the formation

of other three-dimensional materials. It is therefore still a

challenge to extend the fabrication of single-crystalline tubular

nanostructures from lamellar to 3D materials.

Proteins from bones, shells, and a number of micro-

organisms can control the nucleation and growth of inorganic

structures with remarkable precision.6–8 Bio-inspired assis-

tance has also been applied to the synthesis of inorganic

materials in vitro.7 For example, Pender et al. reported the

formation of silica- and titania-coated carbon nanotubes using

a multifunctional peptide consisting of a nanotube-binding

domain and an alkoxide-precipitating domain derived from

the silica-precipitating protein silaffin.9 These bio-inspired

techniques require the identification of specific biological

molecules to catalyze the formation of nanoparticles, and

involve time-consuming and often complex methodologies to

generate the biological template. In contrast, here we applied

the optionally available proteins from any egg as a nano-

reactor for the scalable synthesis of Fe3O4 nanotubes. The

growth scheme of Fe3O4 nanotubes is shown in Fig. 1. In the

main, the surface of netlike proteins is adequate for the growth

of oxide semiconductor. Proteins present an important advan-

tage in having high affinity for metal ions, so that the particle

will intercalate semiconductor precursors very efficiently.10

Thus, these precursors are preconcentrated at the proteins

where the chemical environment is adjusted, suitable for the

subsequent semiconductor growth process. The occurrence of

tubes provides an insight into the possible mechanism of their

formation, suggesting that the formation of tubular structures

by fundamentally similar peptides is consistent with the

closure of a two-dimensional layer.11

The magnetic Fe3O4 nanotubes were obtained by hydro-

thermal treatment of a Fe2(SO4)3 solution in the presence of

egg albumin. Typically, 20 ml of aqueous Fe2(SO4)3 solution

(0.05 M) and 5 ml of egg albumin were mixed with stirring.

After stirring for 5 min, 8 ml absolute ethanol (CH3CH2OH)

were added to the above solution. Finally, 10 ml of 80 wt%

hydrazine hydrate solution (N2H4�H2O) were added dropwise

to the above solution with vigorous stirring. After stirring for

10 min, the mixture was transferred into a 50 ml Teflon-lined

stainless-steel autoclave, which was treated at 140 1C for 24 h.

The SEM images with different magnifications in Fig. 2a

and b show that the as-prepared products (without purifi-

cation) were mainly composed of nanotubes with a regular

shape, together with a few nanosheets. The tubular structures

are uniform and straight with open ends. From the open ends

of the tubes, it was found that the nanotubes have thin walls.

Fig. 2c shows a high-magnification SEM image of a single

nanotube. The open end, as marked with the arrow, can be

clearly seen. Typically, the obtained nanotubes have a uniform

outer diameter of 50–60 nm and the thickness of the tube-wall

Fig. 1 Schematic illustration of the Fe3O4 nanotubes formation

process using proteins as a template. Step 1: Fe31 ions and egg albumin

molecules start to self-assemble and form an organic–inorganic

complex. Then the Fe–N axial coordination of egg albumin N-atoms

to iron ions promotes the growth of aggregates, which continue to grow

into a flake structure. Step 2: the rolling up of the nanosheet gradually

extends along the whole axis to form a nanoscroll. Step 3: hollow tubes

are formed.

College of Chemistry and Materials Science, Anhui Key Laboratoryof Functional Molecular Solids, Anhui Normal University, Wuhu,241000, P. R. China. E-mail: bygeng@mail.ahnu.edu.cn;Fax: (þ86)-553-3869303w Electronic supplementary information (ESI) available: Experimentalprocedures, more SEM and TEM images of the products. See DOI:10.1039/b813071j

This journal is �c The Royal Society of Chemistry 2008 Chem. Commun., 2008, 5773–5775 | 5773

COMMUNICATION www.rsc.org/chemcomm | ChemComm

CuS nanotubes for ultrasensitive nonenzymatic glucose sensorsw

Xiaojun Zhang,*ab Guangfeng Wang,ac Aixia Gu,ac Yan Weiac and Bin Fangac

Received (in Cambridge, UK) 26th August 2008, Accepted 22nd September 2008

First published as an Advance Article on the web 9th October 2008

DOI: 10.1039/b814725f

CuS nanotubes made up of nanoparticles were successfully

prepared in large quantities in an O/W microemulsion system

under low temperature; the as-prepared CuS nanotube modified

electrode was used as an enzyme-free glucose sensor.

Diabetes mellitus is a group of metabolic diseases afflicting

about 200 million people worldwide. For these patients,

frequent testing of physiological glucose levels is critical to

confirm that treatment is working effectively and to avoid a

diabetic emergency. The rising demand for glucose sensors

with high sensitivity, high reliability, fast response, and

excellent selectivity has driven tremendous research efforts

for decades.1,2 Amperometric glucose biosensors are one such

promising methodology. Most previous studies on this subject

involved the use of the enzyme glucose oxidase (GODx),3–8

which catalyzes the oxidation of glucose to gluconolactone.

Owing to the nature of enzymes, the most common and serious

problem with enzymatic glucose sensors lies in their lack of

long-term stability. For instance, the activity of GODx can be

easily affected by temperature, pH value, humidity and toxic

chemicals.9 To solve this problem, nonenzymatic glucose

sensors have also been explored in the hope of improving

the electrocatalytic activity and selectivity towards the oxida-

tion of glucose, such as noble metal-based and alloy-based10–14

amperometric glucose sensors. However, these kinds of elec-

trodes have displayed the drawbacks of low sensitivity, poor

selectivity, high cost and loss of their activity quickly by

adsorbed accumulation of intermediates10 and chloride ions,14

which can result in electrocatalyst surface poisoning.

Recently, CuS was found to show interesting properties

including metal-like electrical conductivity,15 which may have

potential application as electrochemical sensors. The synthesis

of nanotubes has drawn much attention in recent years

because these unique one-dimensional (1D) nanostructures

have excellent electrochemical properties as well as special

applications as electrochemical sensors.16–19 There are several

methods reported for the synthesis of CuS nanotubes.20–23

However, these methods are complicated and high cost, and

furthermore, the conventionally prepared tubular CuS

structures have fewer electron transfer passages resulting in

low sensitivity and so are limited in application, particularly,

in biosystems and biomedicine. Therefore, a facile and cheap

method for the large scale synthesis of uniform CuS nanotubes

made up of nanoparticles are highly valuable.

In this work, CuS nanotubes made up of nanoparticles were

successfully prepared in large quantities in an O/W micro-

emulsion system under low temperature. The prepared mate-

rials which show more electron transfer passages were

successfully applied as an enzyme-free glucose sensor. By

comparison, the electrochemical catalytic activity of the sensor

toward glucose oxidation is better than that of conventionally

prepared CuS nanotubes.

The CuS nanotubes were solvothermally prepared by

reduction of copper nitrate and sodium thiosulfate at 150 1Cfor 12 h in a Teflon lined stainless steel autoclave with a

capacity of 60 mL using a microemulsion system (see ESIw).The yield can reach up to 90 wt%.

The synthesis procedure is shown in Scheme 1. First, oleic

acid, water and poly(vinylpyrrolidone) (PVP) formed the

microemulsion system. In this microemulsion system, oleic

acid was used as a core and water as a shell (Scheme 1(a),

Fig. S1, ESIw) With the reaction prolonged for 2 h, CuS

nanoparticles were synthesized in the water phase and was

composed of hollow CuS nanospheres (Scheme 1(b), Fig. S2,

ESIw) When the reacting time was increased to 6 h, those

hollow CuS nanospheres were further assembled to a tubular

structure (Scheme 1(c), Fig. S3, ESIw) After 12 h, oleic acid/

CuS nanotubes with core/shell structure were obtained

(Scheme 1(d)). Finally, after washing with ethanol to remove

the oleic acid template, the CuS nanotubes were obtained

(Fig. 1).

The XRD pattern (Fig. S4, ESIw) shows that all the

diffraction peaks can be indexed to the hexagonal phase of

the covellite structure (JCPDS no. 6-464) with the P63/mmc

space group and a primitive hexagonal unit cell with a= 3.792

Scheme 1 The formation of CuS nanotubes.

a College of Chemistry and Materials Science, Anhui NormalUniversity, Wuhu, 241000, P.R. China

bAnhui Key Laboratory of Functional Molecular Solids, AnhuiNormal University, Wuhu, 241000, P.R. China

cAnhui Key Laboratory of Chem-Biosensing, Anhui NormalUniversity, Wuhu, 241000, P.R. China.E-mail: zhangxiaojun173@yahoo.com.cn; Fax: +86-553-3869303;Tel: +86-553-3869303w Electronic supplementary information (ESI) available: Detailedexperimental procedures, characterization, XRD, HRTEM, TEM,SEM, EIS, CV, CA data. See DOI: 10.1039/b814725f

This journal is �c The Royal Society of Chemistry 2008 Chem. Commun., 2008, 5945–5947 | 5945

COMMUNICATION www.rsc.org/chemcomm | ChemComm

Synthesis, Characterization, and Catalytic Activity of Rare Earth MetalAmides Supported by a Diamido Ligand with a CH2SiMe2 Link

Yunjun Wu,† Shaowu Wang,*,†,‡ Xiancui Zhu,† Gaosheng Yang,† Yun Wei,† Lijun Zhang,†

and Hai-bin Song§

Institute of Organic Chemistry, Anhui Key Laboratory of Functional Molecular Solids, College ofChemistry and Materials Science, Anhui Normal UniVersity, Wuhu, Anhui 241000, P.R. China;State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences, Shanghai 200032, P.R. China; and State Key Laboratory ofElemento-Organic Chemistry, Nankai UniVersity, Tianjin 300071, P.R. China

Received March 19, 2008

A series of four coordinate rare earth metal amides with general formula {(CH2SiMe2)[(2,6-IPr2C6H3)N]2}LnN-(SiMe3)2(THF) [(Ln ) Yb(2), Y (3), Dy (4), Sm (5), Nd (6)] containing a diamido ligand (CH2SiMe2)[(2,6-iPr2C6H3)N]22-

with a CH2SiMe2 link were synthesized in good yields via reaction of [(Me3Si)2N]3LnIII(μ-Cl)Li(THF)3 with thecorresponding diamine (CH2SiMe2)[(2,6-iPr2C6H3)NH]2 (1). All compounds were fully characterized by spectroscopicmethods and elemental analyses. The structures of complexes 2, 3, 4, 5, and 6 were determined by single-crystalX-ray analyses. Investigation of the catalytic properties of the complexes indicated that all complexes exhibited ahigh catalytic activity on the cyclotrimerization of aromatic isocyanates, which represents the first example ofcyclopentadienyl-free rare earth metal complexes exhibiting a high catalytic activity and a high selectivity oncyclotrimerization of aromatic isocyanates. The temperatures, solvents, catalyst loading, and the rare earth metaleffects on the catalytic activities of the complexes were examined.

Introduction

From an atom-economic perspective, the reactivity ofisocyanates in the coordination sphere of various metalcenters has received some renewed interest recently.1 Suchreactions are quite attractive because they can provide a veryvaluable access to various types of heterocycles as indicatedby some investigations.2 Among these investigations, muchfewer have focused on cyclotrimerization reactions of theisocyanates, especially with rare earth metal complexes as

catalysts.3 Substituted aryl-functionalized isocyanurates areuseful activators for anionic polymerization of ε-caprolactamsto nylon-6 and are known to substantially enhance thestability of polyurethane networks and coating materials withrespect to thermal resistance, flame retardation, chemicalresistance, and film-forming characteristics.3 Different iso-cyanate trimerization catalytic systems have been reported,such as anions or neutral Lewis bases, organic acid salts andtertiary amines, and some metal-based systems.3a,b Conven-tional catalysts for cyclotrimerization of isocyanates sufferfrom low activity, necessitating severe conditions, and poorselectivity resulting in byproducts.4

* To whom correspondence should be addressed. E-mail: swwang@mail.ahnu.edu.cn.

† Anhui Normal University.‡ Chinese Academy of Sciences.§ Nankai University.

(1) (a) Owen, G. R.; White, A. J. P.; Williams, D. J. Organometallics2003, 22, 4511. (b) Wang, H.; Chan, H. S.; Okuda, J.; Xie, Z.Organometallics 2005, 24, 3118. (c) Guiducci, A. E.; Boyd, C. L.;Mountford, P. Organometallics 2006, 25, 1167. (d) Dunn, S. C.;Hazari, N.; Cowley, A. R.; Green, J C.; Mountford, P. Organometallics2006, 25, 1755. (e) Paul, F.; Moulin, S.; Piechaczyk, O.; Le Floch,P.; Osborn, J. A. J. Am. Chem. Soc. 2007, 129, 7294. (f) Duong, H. A.;Cross, M. J.; Louie, J. Org. Lett. 2004, 25, 4679. (g) Rahman, M. S.;Samal, S.; Lee, J. S. Macromolecules 2006, 39, 5009. (h) Ahn, J. H.;Shin, Y. D.; Nath, Y.; Park, S. Y.; Rahman, M. S.; Samal, S.; Lee,J. S. J. Am. Chem. Soc. 2005, 125, 4132. (i) Patten, T. E.; Novak,B. M. J. Am. Chem. Soc. 1996, 118, 1906.

(2) (a) Hoberg, H. J. Organomet. Chem. 1988, 358, 507. (b) Hoberg, H.;Guhl, D. J. Organomet. Chem. 1989, 375, 245. (c) Hoberg, H.; Guhl,D. J. Organomet. Chem. 1989, 378, 279. (d) Hoberg, H.; Barhausen,D.; Mynott, R.; Schroth, G. J. Organomet. Chem. 1991, 410, 117. (e)Hoberg, H.; Nohlen, M. J. Organomet. Chem. 1991, 412, 225. (f) Zhou,H. B.; Alper, H. J. Org. Chem. 2003, 68, 3439. (g) Hsieh, J. C.; Cheng,C. H. Chem. Commun. 2005, 4554.

(3) (a) Tang, J. S.; Verkade, J. G. Angew. Chem., Int. Ed. Engl. 1993, 32,896. (b) Tang, J. S.; Verkade, J. G. J. Org. Chem. 1994, 59, 4931. (c)Foley, S. R.; Yap, G. P.; Richeson, D. S. Organometallics 1999, 18,4700. (d) Foley, S. R.; Zhou, Y.; Yap, G. P. A.; Richeson, D. S. Inorg.Chem. 2000, 39, 924.

Inorg. Chem. 2008, 47, 5503-5511

10.1021/ic800496d CCC: $40.75 © 2008 American Chemical Society Inorganic Chemistry, Vol. 47, No. 12, 2008 5503Published on Web 05/20/2008

Facile Production of Self-Assembly Hierarchical Dumbbell-LikeCoOOH Nanostructures and Their Room-TemperatureCO-Gas-Sensing Properties

Baoyou Geng,* Fangming Zhan, Han Jiang, Zhoujing Xing, and Caihong Fang

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,Anhui Normal UniVersity, Wuhu 241000, P. R. China

ReceiVed March 3, 2008; ReVised Manuscript ReceiVed May 12, 2008

ABSTRACT: In this paper, we report a simple and novel coordination compound precursor route to synthesize the hierarchical dumbbell-like CoOOH nanostructures in high yield. A possible growth mechanism governing the formation of such nanostructures is discussed. TheCO-gas-sensing properties of the as-synthesized nanostructures are investigated in detail. The dumbbell-like CoOOH nanostructures havea large active surface area of {110} facets, which can provide sufficient space for the interaction between CoOOH and the detected gases.As a result, the as-prepared dumbbell-like CoOOH nanostructures exhibit a superior sensitivity to CO at room temperature, as well as goodreproducibility and short response/recovery times. The as-prepared CoOOH nanostructures could have potential applications in nanosensors.

Research into nanostructures has increased recently because oftheir unique electrical, optical, magnetic, and catalytic characteristicsin comparison with the bulk materials. Despite the rapid develop-ment in various synthetic technologies of nanostructures in the pastfew years, the industrial applications of nanostructures imposehigher requirements.1 For example, when nanosized catalysts wereused directly, the separation of nanostructures is difficult owing tothe colloidal properties.1,2 If fabricated into bulk materials, thediffusion barrier limits the mass transportation to and from the activesites,1-6 which is quite important to the applications like gassensing, catalysis, ion-exchange separation, and so on. Therefore,if functional nanocrystals are organized into hierarchical micro/nanostructures, which can provide more space for mass transporta-tion-related applications, it is of great scientific and practical value.2

Early in the 21st century, it was found that the cobalt oxidecatalyst (Co3O4) could facilitate the rapid oxidation of CO at atemperature of 200 °C or lower.7 In the latest approach to improvea Co3O4-based gas sensor, cobalt oxyhydroxide (CoOOH) has beenproposed as an alternative material for CO detection at lowtemperatures.8 Therefore, an improvement in CO sensitivity andselectivity, specifically for the measurement of low CO concentra-tions, is imperative for successful early toxicosis detection. Contraryto Co3O4, CoOOH is a nonstoichiometric oxyhydroxide and hasmore oxidation state Co (3+) than in Co3O4. Several investigatorshave reported to date that cobalt Co3+ ions are active for oxidationof CO,8 and consequently, CoOOH can be used as a CO sensingmaterial in the semiconductor CO sensors. In general, CoOOH ismainly synthesized via the conventional solution method, whichneeds higher sodium hydroxide concentration,9 higher tempera-ture,10 or longer reaction time.11,12 All mentioned above need thetransformation from Co (2+) to Co (3+), which is the difficultprocess. As we know, Co (2+) is much steadier than Co (3+) inmost situations. Therefore, the development of a facile route toobtain the steady Co (3+) precursor is very important to theformation of CoOOH nanostructures. We found that Co (3+)6-nitrite complex {M3[Co(NO2)6], M ) K+, Na+} is a steady Co(3+) compound, from which the CoOOH can be obtained easilythrough hydrolysis and thermolysis route. The experimental processwas performed through treatment of an K3[Co(NO2)6] aqueoussolution (0.01 M) with NaOH concentrations of 2 M at 80 °C for60 min. The gas sensors properties of the as-synthesized nano-structures are investigated in detail, which reveals that the as-prepared CoOOH nanostructures exhibit a superior sensitivity to

CO at room temperature, as well as good reproducibility and shortresponse/recovery times. The as-prepared CoOOH nanostructurescould have potential applications in nanosensors.

2. Experimental Section. All chemicals were analytical gradeand used as received without further purification.

2.1. Synthesis of K3[Co(NO2)6]. In a typical procedure, 0.145g of cobaltous nitrate [Co(NO3)2 ·H2O] was dissolved into 11 mLof distilled water with vigorous stirring. Then, 0.5 g of analyticallypure kalium nitrite (KNO2) and 4 mL 36 wt % acetic acid(CH3COOH) were added to the above solution. After being stirredwith a magnetic blender for 5 min, the solution turned yellow. TheK3[Co(NO2)6] solution is obtained according to the followingequations

Co2++ 7NO2-+ 3K++ 2H+fK3[Co(NO2)6]+NO+H2O

2.2. Synthesis of Dumbbell-Like CoOOH. The K3[Co(NO2)6]solution was stirred, then aqueous NaOH solution (10 mL, 5 M)was added dropwise. Finally, the NaOH concentration of thismixture solution was 2 M. Then the mixed solution was heated to80 °C and kept for 60 min under stirring in a beaker. After thereaction was completed, the beaker was allowed to cool to roomtemperature naturally. The precipitate was separated by centrifuga-tion, washed with distilled water and absolute ethanol, and driedunder a vacuum at 60 °C.

2.3. Characterization. X-ray powder diffraction (XRD) wascarried out on an XRD-6000 (Japan) X-ray diffractometer with CuKR radiation (λ ) 1.54060 Å) at a scanning rate of 0.05 ° s-1.Scanning electron microscopy (SEM) micrographs were taken usinga Hitachi S-4800 scanning electron microscope. Transmissionelectron microscopy (TEM) micrographs and High-resolutiontransmission electron microscopy (HRTEM) was performed using

* Corresponding author. Fax: 86-553-3869303. E-mail:bygeng@mail.ahnu.edu.cn.

Figure 1. gas sensor fabricated with a CoOOH nanocomposite film ona ceramic tube. (a) Top view photograph of the gas-sensor structure;(b) side view photograph of the gas sensor.

CRYSTALGROWTH& DESIGN

2008VOL. 8, NO. 10

3497–3500

10.1021/cg8002367 CCC: $40.75 © 2008 American Chemical SocietyPublished on Web 08/28/2008

Surface modification of polypropylene macroporousmembrane to improve its antifouling characteristics ina submerged membrane-bioreactor: H2O plasma treatment

Hai-Yin Yu*, Zhao-Qi Tang, Lei Huang, Gang Cheng, Wei Li, Jin Zhou,Meng-Gang Yan, Jia-Shan Gu, Xian-Wen Wei

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,

Anhui Normal University, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:

Received 12 March 2008

Received in revised form

14 May 2008

Accepted 20 May 2008

Available online 24 June 2008

Keywords:

Antifouling characteristics

Polypropylene macroporous

membrane

H2O plasma treatment

Submerged membrane-bioreactor

Wastewater treatment

a b s t r a c t

To improve the antifouling characteristics of polypropylene hollow fiber macroporous

membranes in a submerged membrane-bioreactor for wastewater treatment, the

membranes were surface modified by H2O plasma treatment. Structural and morphological

changes on the membrane surface were characterized by X-ray photoelectron spectros-

copy (XPS) and field emission scanning electron microscopy (FE-SEM). The change of

surface wettability was monitored by contact angle measurement. The static water contact

angle of the modified membrane reduced obviously with the increase of plasma treatment

time. The total surface free energy and its dispersive component decreased, while the polar

component increased with the increase of treatment time. The relative pure water flux for

the modified membranes increased gradually with the increase of plasma treatment time.

The tensile strength and the tensile elongation at break for the membranes decreased after

plasma treatment. After continuous operation in a submerged membrane-bioreactor for

about 68 h, flux recovery after water and caustic cleaning, flux ratio after fouling were

improved by 2.0, 3.6 and 22.0%, while reduction of flux was reduced by 1.1% for the

1 min H2O plasma treated membrane, compared to those of the unmodified membrane.

ª 2008 Elsevier Ltd. All rights reserved.

1. Introduction

The membrane bioreactor (MBR) process takes advantage of

rapid developments in membrane manufacturing and has

the potential to fundamentally advance biological treatment

processes. With its unique features of excellent effluent

quality, ensured biomass–water separation, small footprint

demand, better operational control of sludge concentration,

and other biological conditions, MBR is increasingly being

used in wastewater treatment and the reclamation of treated

effluents. However, membrane fouling is still the major limi-

tation to the large-scale application of the MBR process

(Le-Clech et al., 2006, 2007;Wang and Li, 2008). Physical rinsing

and chemical cleaning have to be applied frequently in the

operation of an MBR, which increases the operation cost and

shortens the life of the membrane (Zhang et al., 2007). Thus,

it is necessary to obtain membranes with better antifouling

characteristics for fouling control in MBR applications.

Polypropylene macroporous membrane exhibits high

potentials for comprehensive applications due to their high

void volume, well-controlled porosity, high thermal and

chemical stability, and low cost. However, the low energy

surface and relatively high hydrophobicity lead to membrane

fouling (Yang et al., 2005). In an attempt to improve the

* Corresponding author. Tel.: þ86 553 599 1165; fax: þ86 553 386 9303.E-mail address: yhy456@mail.ahnu.edu.cn (H.-Y. Yu).

Avai lab le a t www.sc iencedi rec t .com

journa l homepage : www.e lsev ie r . com/ loca te /wat res

0043-1354/$ – see front matter ª 2008 Elsevier Ltd. All rights reserved.doi:10.1016/j.watres.2008.05.028

wat e r r e s e a r c h 4 2 ( 2 0 0 8 ) 4 3 4 1 – 4 3 4 7

Fabrication, Characterization, and Strong Exciton Emission of Multilayer ZnTe NanowireSuperstructures

Yijun Guo,† Baoyou Geng,*,† Li Zhang,‡ Fangming Zhan,† and Jiahui You†

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,Anhui Normal UniVersity, Wuhu 241000, People’s Republic of China, and Anhui Key Laboratory of SpinElectron and Nanomaterials (CultiVating Base), Department of Chemistry and Biology, Suzhou UniVersity,Suzhou 234000, People’s Republic of China

ReceiVed: September 12, 2008; ReVised Manuscript ReceiVed: October 19, 2008

In this paper, multilayer superstructures of single-crystalline ZnTe nanowire films have been prepared througha new growth process: well-aligned ZnTe nanowires congregate into nanowire film. The growth processtakes place discontinuously and consequently produces many layers of aligned ZnTe nanowire superstructures.These interesting findings are apparently different from the conventional vapor-liquid- solid (VLS) processbut following a new multiple nucleation growth model. The intriguing growth mode of multilayersuperstructures of aligned ZnTe nanowires may enrich our understanding of the growth mechanism ofnanowires. The photoluminescence spectrum of the obtained multilayer ZnTe NWs superstructures exhibitsstrong free exciton emission peak and relatively weak Ia line, indicating that the layers are of high quality,which may have potential applications in nanodevices.

Introduction

One-dimensional (1D) nanoscale semiconductors have at-tracted much attention due to their importance in understandingthe fundamental roles of dimensionality and quantum sizeeffects. Potential applications for these structures include asbuilding blocks for electronic and optical nanodevices.1-6

Current challenges in the synthesis of 1D nanomaterialsessentially comprise the controls over a single nanowire (NW)and the assembly of an ensemble of NWs. As far as a singlenanowire is concerned, the control of morphology, size, andgrowth direction is important. However, the impact of alignedand arranged 1D nanomaterial patterns would be tremendousin many areas, from nanoscale electronics and optoelectronicsto molecular sensing.7 Recent research on NWs is expandingrapidly into their assembly to two- (2D) and three-dimensional(3D) ordered superstructures.8-12

In past years, many methods have been developed for thefabrication of nanowire arrays including template methods,13-16

catalytic growth,17-19Langmuir-Blodgett and fluidic alignmenttechniques,20 and electrospinning,21 etc. Especially, the vapor-liquid-solid (VLS) growth mechanism has been widely adoptedto understand the growth of various kinds of 1D NWs andnanotubes of inorganic materials.22,23 In the conventional VLSmechanism, a nanoscale alloy droplet acting as a catalytic siteabsorbs a gas-phase reactant, directs the nucleation and thegrowth of a nanostructured crystal, and confines the diameterof the crystalline nanowire/nanotube.24 A common morphologi-cal feature of the VLS grown nanowires/nanotubes is that onecatalytic nanoparticle usually catalyzes the growth of only onenanowire/nanotube and is attached to one tip of the nanowire/nanotube. Recently, a feature quite different from those in theconventional VLS process that has been demonstrated in several

studies is that one micrometer-sized Ga droplet can simulta-neously catalyze the growth of many SiOx NWs with differentnanostructures.25-30 However, a catalytic droplet usually pro-motes the growth of the nanostructure only once. Therefore,the yield of the NWs is essentially controlled by the number ofcatalytic droplets involved in the activation reaction. An amazinggrowth phenomenon has been observed by Pan et al. in thesynthesis of silica NWs, in which the highly aligned NWs tendto grow batch by batch from one catalytic droplet. For each

* To whom correspondence should be addressed. E-mail: bygeng@mail.ahnu.edu.cn.

† Anhui Normal University.‡ Suzhou University.

Figure 1. Apparatus and temperature profile of the furnace when thecenter temperature is 700 °C. (The location value is the distance relativeto the furnace center).

J. Phys. Chem. C 2008, 112, 20307–20311 20307

10.1021/jp8081497 CCC: $40.75 © 2008 American Chemical SocietyPublished on Web 12/02/2008

Microwave-Assisted Synthesis and Photocatalytic Properties of Carbon Nanotube/ZincSulfide Heterostructures

Huaqiang Wu,*,†,‡ Qianyi Wang,† Youzhi Yao,† Cheng Qian,† Xiaojun Zhang,†,‡ andXianwen Wei†,‡

College of Chemistry and Materials Science, Anhui Normal UniVersity, Wuhu 241000,People’s Republic of China, and Anhui Key Laboratory of Functional Molecular Solids, Anhui NormalUniVersity, Wuhu 241000, People’s Republic of China

ReceiVed: August 2, 2008; ReVised Manuscript ReceiVed: August 28, 2008

The multiwalled carbon nanotubes (MWCNTs) wrapped with face-centered cubic ZnS nanospheres with auniform and small diameter have been prepared to form MWCNT/ZnS heterostructures by microwaveirradiation. Zinc acetate (Zn(Ac)2) and thioacetamide (TAA) were used as the zinc and sulfur sources,respectively. The dispersion, morphology, ratio of loading, and size of the ZnS nanospheres in the range of11.7 to 24.5 nm can be controlled easily by adjusting the microwave power, the initial concentration ofZn(Ac)2, and the molar ratios of Zn(Ac)2/TAA and Zn(Ac)2/MWCNTs. The heterostructures have beencharacterized by X-ray powder diffraction, and scanning and transmission electron microscopy. The resultsshow that the surfaces of MWCNTs are not only randomly decorated with ZnS layers composed of uniformZnS nanoparticles but also show that some spherelike ZnS nanoparticles are aggregated and deposited on theZnS layers. A photoluminescence spectrum showed that the MWCNT/ZnS heterostructures feature a broadblue emission at around 432 nm (λex ) 376 nm). The MWCNT/ZnS heterostructures also show an excellentphotocatalytic activity toward the photodegradation of methyl orange.

Introduction

The study of coating carbon nanotubes with inorganicfunctional materials is now becoming a promising and chal-lenging area of research owing to their unique applications suchas nanoelectronic devices,1 support media in heterogeneouscatalysis, 2 fuel cells,3 magnetic recording,4 and optoelectronicdevices.5 To optimize the use of carbon nanotubes in variousapplications, it is necessary to attach functional groups or othernanostructures to their surface. The combination of the distinc-tive properties of carbon nanotubes and other inorganic func-tional materials are expected to apply in field emission displays,nanoelectronic devices, novel catalysts, and polymer or ceramicreinforcement.6,7 Thus, it is significant to assemble carbonnanotubes and other inorganic functional materials into hetero-structures. Zinc sulfide is an important II-VI semiconductorwith bandgap energy of 3.65 eV; it has been used widely indisplays, sensors, and lasers for many years.8 Recent studieshave revealed that ZnS nanospheres display excellent photo-catalytic activity toward the photodegradation of eosin B underthe irradiation of ultraviolet-visible (UV-vis) light.9 There arefew reports about the multiwalled carbon nanotubes (MWCNTs)coated with ZnS; for example, the different morphologies ofZnS were grown on the outermost shells of MWCNTs by heattreatment of Zn under an Ar/10% H2S atmosphere;10 thecontrolled synthesis of MWCNT/ZnS-coated CdSe quantum dotheterojunctions was carried out using the ethylene carbodiimidecoupling procedure;11 noncovalently functionalized MWCNTswith sodium dodecyl sulfate were coated with ZnS layers by

an in situ synthesis method;12 MWCNT/ZnS heterostructureswere obtained by a combination of ultrasonic and heat treat-ments.13 More recently, Gu et al.14 also have synthesizedMWCNT/ZnS heterostructures by a solution chemical method.Therefore, it is necessary to find an efficient and easy methodcombining synthesis and coating in one step to form the tubularheterostructures with inorganic nanocrystals attached on carbonnanotubes.

Microwave irradiation is an attractive method for synthesisof nanocrystals due to its unique reaction effects such as rapidvolumetric heating and the consequent dramatic increase inreaction rate, etc.15 In comparison with conventional methods,microwave-assisted method has the advantages of short reactiontime, small particle size, narrow particle size distribution, andhigh purity. In this study, MWCNTs wrapped with a uniformand small diameter of ZnS nanospheres were prepared usingmicrowave irradiation. Zinc acetate (Zn(Ac)2) and thioacetamide(TAA) were used as zinc source and sulfur sources, respectively.By adjustment of the microwave power, the initial concentrationof Zn(Ac)2, and the molar ratios of Zn(Ac)2/TAA and Zn(Ac)2/MWCNTs, the size of the uniform as-prepared ZnS nanospheresin the range of 11.7-24.5 nm can be controlled. The MWCNT/ZnS heterostructures feature a blue emission at around 432 nm(λex ) 376 nm), which exhibited the excellent photocatalyticactivity for the photocatalytic degradation of sodium p-dim-ethylaminoazobenzenzene sulfonate (i.e., methyl orange). Theformation mechanism of MWCNT/ZnS heterostructures isdiscussed on the basis of the experimental results.

Experimental Procedures

Chemicals. Zn(Ac)2 ·2H2O, HNO3, thioacetamide, methylorange, and ethanol were purchased from Shanghai ChemicalCorp.; all chemicals are analytical grade without furtherpurification. The MWCNTs with a purity of about 95% were

* To whom correspondence should be addressed. E-mail wuhuaq@mail.ahnu.edu.cn.

† College of Chemistry and Materials Science, Anhui Normal University.‡ Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal

University.

J. Phys. Chem. C 2008, 112, 16779–16783 16779

10.1021/jp8069018 CCC: $40.75 © 2008 American Chemical SocietyPublished on Web 10/08/2008

Seed-Mediated Growth Method for Epitaxial Array of CuO Nanowires on Surface of CuNanostructures and Its Application as a Glucose Sensor

Xiaojun Zhang,*,†,‡ Guangfeng Wang,†,§ Wei Zhang,†,§ Nianjun Hu,† Huaqiang Wu,†,‡ andBin Fang†,§

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, and AnhuiKey Laboratory of Chem-Biosensing, Anhui Normal UniVersity, Wuhu 241000, People’s Republic of China

ReceiVed: January 18, 2008; ReVised Manuscript ReceiVed: March 30, 2008

The preparation and characterization of a large-scale epitaxial array of single-crystalline CuO nanowires (NWs)on the surface of a Cu nanostructure (Cu-CuO nanocomposite) by a simple liquid-solid growth process atroom temperature is demonstrated. The field-emission scanning electron microscopy image analysis indicatedthat the NWs are 50-80 nm wide at the root and 300-400 nm long. The high-resolution transmission electronmicroscopy study on individual CuO NWs revealed that the NWs are single crystalline with a growth orientationof [110]. X-ray powder diffraction and energy dispersive X-ray analysis of the samples revealed that theCuO NWs only cover the surface of dendritic Cu and that Cu dendrites still exist in the center of the Cu-CuOnanocomposite. Electrochemical impendance spectroscopy and cyclic voltammetry showed that the Cu-CuOnanocomposite has a stronger ability to promote electron transfer than the CuO NWs or CuO nanoparticlesindividually. The Cu-CuO nanocomposite was successfully used to modify a glassy carbon electrode todetect H2O2 and glucose with chronoamperometry. The result shows that the Cu-CuO nanocomposite maybe of great potential as H2O2 and glucose electrochemical sensors.

Introduction

As a p-type semiconductor with a narrow band gap (1.2 eV),cupric oxide (CuO) has been widely exploited for a number ofinteresting properties.1–3 For example, monoclinic CuO solidbelongs to a particular class of materials known as Mottinsulators, whose electronic structures cannot be simply de-scribed using conventional band theory.4,5 With regard to itscommercial value, CuO has been widely studied for use as apowerful heterogeneous catalyst to convert hydrocarbons com-pletely into carbon dioxide and water.6–9 Cupric oxide is alsopotentially useful in the fabrication of lithium-copper oxideelectrochemical cells, and the relation between the microstruc-ture of solid CuO and its potential as a cathode material hasbeen systematically investigated.10–13 As already has beendemonstrated for many other semiconductors (e.g., Si, CdSe,and ZnO), it is reasonable to expect that the ability to processCuO into nanostructured materials should enrich our under-standing of its fundamental properties and enhance its perfor-mance in currently existing applications.14–23 Because theproperties of materials at the nanoscale regime are stronglyinfluenced by their shape and dimensional constraints,24 it isexpected that the synthesis of CuO compounds into nanostruc-tured materials, particularly those with a one-dimensional (1-D) structure such as nanowires (NWs), nanotubes, nanobelts,etc., could enhance its intrinsic characteristics for use in existingapplications.

Recently, several techniques for the synthesis of 1-D struc-tures of CuO have been made available. A hydrothermalapproach for the synthesis of quasi-1-D CuO nanostructures alsowas reported by Yang et al.25 By following a hydrothermal

reaction of CuSO4 and ethylene glycol in alkaline conditions at200 °C, branched CuO nanorods with sizes up to severalhundreds of nanometers can be produced. Nanorods werecharacterized with a single-crystalline structure. Despite thesetechniques providing an interesting synthetic procedure forproducing high quality 1-D CuO structures, another challenge,namely, finding a procedure to attach these nanostructures ontoa certain solid support, particularly in an epitaxial array, shouldbe resolved first to make this kind of nanostructure viable inexisting applications, which appears to require much effort withlimited success. Xia et al. presented a fascinating strategy forthe realization of a epitaxial array of CuO NWs growing on aCu substrate, which involved heating the Cu substrates atmoderately high temperatures (typically 400 °C) in an oxygenatmosphere via a vapor solid process.26 The NWs mainly arecharacterized by a bicrystalline structure with a twin-planeoriented parallel to the longitudinal axis of the NW that growalong the κ direction. Yang et al. presented another potentialmethod for growing CuO NWs epitaxially on Cu substrates thatwas achieved by using a liquid-solid phase technique.27 Akrajasand Munetaka demonstrated the growth of a large-scale epitaxialarray of CuO NWs on different materials surfaces, such as ITO,glassy carbon (GC), etc., by applying a simple seeding process.28

However, despite these approaches providing an elegant strategyfor producing a highly crystalline epitaxial array of CuO NWs,the new characteristics that are most likely acquired from thesenanostructures might be strongly influenced by the bulk proper-ties of Cu, CuO, or other nonelectric substrates because theycan grow only on the bulk substrate. Hence, their functionalitiesin applications can be limited and restrained. However, to takea vast benefit from the superior characteristics of these nano-structures and to extend their application ranges, any effortstoward enabling the CuO NWs to grow on the nanostructureand making the growth easy should be demonstrated.

* Corresponding author. E-mail: zhangxiaojun173@yahoo.com.cn.† College of Chemistry and Materials Science.‡ Anhui Key Laboratory of Functional Molecular Solids.§ Anhui Key Laboratory of Chem-Biosensing.

J. Phys. Chem. C 2008, 112, 8856–88628856

10.1021/jp800694x CCC: $40.75 © 2008 American Chemical SocietyPublished on Web 05/28/2008

Different CuO Nanostructures: Synthesis, Characterization, and Applications for GlucoseSensors

Xiaojun Zhang,*,†,‡ Guangfeng Wang,†,§ Xiaowang Liu,†,‡ Jingjing Wu,† Ming Li,† Jing Gu,†Huan Liu,† and Bin Fang†,§

College of Chemistry and Materials Science, Anhui Normal UniVersity, Wuhu 241000,People’s Republic of China, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal UniVersity,Wuhu 241000, People’s Republic of China, and Anhui Key Laboratory of Chem-Biosensing, Anhui NormalUniVersity, Wuhu 241000, People’s Republic of China

ReceiVed: August 5, 2008; ReVised Manuscript ReceiVed: August 22, 2008

Three different nanostructures of CuO (wires, platelets, and spindles) have been synthesized by one precursor.First, Cu(OH)2 nanowires have been prepared by a two-step, template-free, wet chemical approach. And thenthe transformation from the 1D Cu(OH)2 nanostructures to a variety of novel CuO nanostructures has beenrealized by thermal dehydration of the as-prepared Cu(OH)2 in solution. The electrochemical characters ofthe three different nanostructures are studied by their investigation of electrochemical impendance spectrumand cyclic voltammetry. A comparison of the three nanostructures showed us an attractive phenomenon, thatis, the electron transfer ability of CuO nanospindles was stronger than that of CuO nanowires or nanoplatelets.We suggest the possible reason is the assembly of the nanostructrue. The electrochemical response of theas-prepared samples on H2O2 is also investigated, and good application in electrochemical detecting of glucoseis exhibited.

1. Introduction

As a p-type semiconductor with a narrow band gap (1.2 eV),cupric oxide (CuO) has been widely exploited for a number ofinteresting properties.1-5 Because of its photoconductive andphotochemical properties, CuO is a promising material forfabricating solar cells and lithium ion batteries.6-9 Furthermore,because CuO has complex magnetic phases and forms the basisfor several high-Tc superconductors and materials with giantmagnetoresistance,10 it has been used in the preparation of awide range of organic-inorganic nanostructured composites thatpossess unique characteristics such as high thermal and electricalconductivities as well as high mechanical strength and high-temperature durability.11 Therefore, on the basis of the funda-mental and practical importance of CuO nanomaterials, well-defined CuO nanostructures with various morphologies havebeen fabricated.

During the past few years, nanoscaled materials have attractedextensive attention due to their unique properties.12-17 It iswidely accepted that these properties are not only closely relatedto their sizes but also to their shapes. Therefore, controllingthe morphologies of nanomaterials is one of the most importantissues and effective ways to obtain desirable properties.18-23

The preparation of metal nanostructures has received muchattention because of their potential applications in the fields ofinformation storage, catalysis, electronics, and optics.24-28 Asshape-controlled synthesis was addressed, nanostructures withvarious regular shapes such as cubes, polyhedral, wires, prisms,and rods were fabricated using a variety of methodologies.29-39

Because the properties of materials at the nanoscale regime are

strongly influenced by their shape and dimensional, it is expectedthat the synthesis of the CuO compound into various shape anddimensional nanostructured materials is valuable, and it is moreattractive to study its intrinsic characteristics for use in existingapplications.

Among CuO nanostrutures, 1D CuO nanomaterials have beenlargely prepared.40-44 In particular, recent research indicates that2D and 3D structures of CuO nanomaterials have been widelyfocused through different routes. Some high dimensionalstructures of CuO nanomaterials have been prepared by materialscientists. For example, Hsieh’s group has fabricated largequantities of well-ordered CuO nanofibers on the basis of a self-catalytic growth mechanism.45 Zeng’s group has successfullyprepared mesoscale organization of CuO nanoribbons.46 Yang’sgroup has synthesized CuO nanoribbons arrays on a coppersurface.47

In this work, three different nanostructures of CuO (wires,platelets, and spindles) have been synthesized by one precursor.First, Cu(OH)2 ·H2O nanowires have been prepared by a two-step, template-free, wet chemical approach. And then thetransformation from the 1D Cu(OH)2 ·H2O nanostructures to avariety of novel CuO nanostructures has been realized bythermal dehydration of the as-prepared Cu(OH)2 ·H2O in solu-tion. The electrochemical characters of the three differentnanostructure are studied by their investigation of electrochemi-cal impendance spectrum (EIS) and cyclic voltammetry (CV),and a comparison with each other is made. An attractivephenomenon of the electron transfer ability was found, that is,the electron transfer ability of CuO nanospindles was strongerthan that of CuO nanowires or nanoplatelets. And a possibleexamination about the assembly of the nanostructrue wasproposed to account for the phenomenon in this paper. At last,the electrochemical response of the as-prepared samples on H2O2

is also investigated the amperometric detection of H2O2 becauseH2O2 is released during the oxidation of glucose by GOx in the

* Towhomcorrespondenceshouldbeaddressed.E-mail:zhangxiaojun173@yahoo.com.cn.

† College of Chemistry and Materials Science, Anhui Normal University.‡ Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal

University.§ Anhui Key Laboratory of Chem-Biosensing, Anhui Normal University.

J. Phys. Chem. C 2008, 112, 16845–16849 16845

10.1021/jp806985k CCC: $40.75 © 2008 American Chemical SocietyPublished on Web 10/04/2008

Fused PolycyclesDOI: 10.1002/ange.200901246

One-Step Synthesis of the Benzocyclo[penta- to octa-]isoindole Core**Yimin Hu,* Chenli Yu, Dong Ren, Qiong Hu, Lidong Zhang, and Dong Cheng

Owing to the prevalence of heterocyclic compounds inmedicinal chemistry and natural products, the developmentof new transition-metal-catalyzed reactions for the formationof fused heterocycles continues to be an active area ofresearch.[1–3] The construction of such ring systems by meansof C�H activation[4] and Heck coupling[5] is a complementaryapproach to remarkably powerful domino reactions.[6]

Recently, Yu and co-workers reported a promising C�Hactivation route for the preparation of indolines and tetrahy-droisoquinolines.[7] Fujii and co-workers developed a palla-dium-catalyzed C(sp3)�H activation for the direct prepara-tion of indoline derivatives.[8] In a particularly straightforwardapproach, Chang and co-workers reported the synthesis ofcondensed pyrroloindoles through the intramolecular func-tionalization of a pyrrole C�H bond.[9] These synthesesexhibit good selectivity and high atom economy, and arecarried out under mild reaction conditions at low catalystloadings.[10,11]

Herein, we report a novel domino cyclization methodinvolving carbopalladation and the subsequent regioselectivefunctionalization of an unactivated C�H bond for thepreparation the benzocyclo[penta- to octa-]isoindole core(Scheme 1). The fused heterocyclic ring systems contain

tertiary stereocenters at the A–B and B–D ring junctures.Control of the relative and absolute configurations of these

stereocenters, and the construction of the tetracyclic frame-work of the complex heterocyclic system, represent signifi-cant synthetic challenges. In a typical procedure, a mixture ofN-allyl-N-(cyclohex-2-enyl)-4-methylbenzenesulfonamide(1b), 4-bromobenzonitrile, tributylamine, Pd(OAc)2, andPPh3 was heated in N,N-dimethylformamide (DMF) underan argon atmosphere overnight. Standard workup proceduresafforded the coupled products with excellent regio- andstereoselectivity for most dienes (Table 1). The temperature iscrucial for this reaction: No domino reaction occurred below130 8C; in contrast, higher reaction temperatures (> 145 8C)led to the decomposition of 3bb, as indicated by TLC. The useof other phosphine compounds, such as PEt3, P(OEt)3, or 1,2-bis(diphenylphosphanyl)ethane, led to very similar results tothose obtained with PPh3. Among the catalysts tested ([Pd-(PPh3)4], [Pd(dba)2]/PPh3 (dba= dibenzylideneacetone),PdCl2/PPh3, Pd(OAc)2/PPh3, [AuCl(PPh3)]/AgSbF6, [Rh-(cod)2]

+SbF6� (cod= 1,5-cyclooctadiene)), the combination

Pd(OAc)2/PPh3 was found to be the most effective. N,N-Dimethylformamide proved to be a better solvent than N,N-dimethylacetamide, toluene, or 1,4-dioxane for this reaction;nBu3N was more effective than any inorganic bases tested.Thus, the following standard reaction conditions wereselected for this study: The diene (1 equiv) was treated withan aryl halide (1.1 equiv) in the presence of Pd(OAc)2(2 mol%), Ph3P (4 mol%), and nBu3N (2 equiv) in DMF at140 8C.

A number of dienes and substituted aryl halides aresuitable for this palladium-catalyzed cross-coupling reaction(Table 1). A range of dodecahydrobenzo[f]cycloocta[cd]-isoindoles were isolated readily in good to excellent yieldswhen aryl halides with electron-withdrawing groups wereemployed (Table 1; entries 4–13, 16, 17, and 19). The electron-withdrawing group could be a methoxycarbonyl, keto,sulfonyl, or cyano group. Electron-donating substituentscould be present on the benzene ring, and ortho- and meta-substituted aryl halides were also suitable substrates (Table 1;entries 10 and 18–20). When 1-bromonaphthalene was used inthe reaction with the cyclohexenyl sulfonamide 1b, thedesired isoindole with a fused cyclohexyl ring was obtainedin very good yield (Table 1; entry 3).

Differences in the diene substrates have much influenceon the domino reaction. The output of reactions of substrates1a and 1c with aryl halides were much lower than that of thecorresponding reactions of 1b, 1d, 1 f, and 1g, probablybecause of the high torsional strain of the cycloalkenyl group(cyclopentenyl or cycloheptenyl). The yield of the desiredproduct was reduced when 4-iodobenzonitrile was employed(Table 1, entry 14). Interestingly, it was found that the C�Brbond reacted selectively with the diene when bromine andchlorine substituents were both present on the benzene ring(Table 1; entry 20).

Scheme 1. Target benzocyclo[penta- to octa-]isoindole core structures.

[*] Prof. Dr. Y. Hu, C. Yu, D. Ren, Q. Hu, L. Zhang, D. ChengLaboratory of Functional Molecular Solids, Ministry of EducationAnhui Key Laboratory of Functional Molecular-Based MaterialsInstitute of Organic ChemistrySchool of Chemistry and Materials ScienceAnhui Normal University, Wuhu, Anhui 241000 (China)Fax: (+86)553-388-3517E-mail: yiminhu@mail.ahnu.edu.cn

[**] Support of this research by grants from the National ScienceFoundation of China (20872002, 20572001) and the EducationDepartment of Anhui Province (TD200707) is gratefully acknowl-edged.

Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/anie.200901246.

Zuschriften

5556 � 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. 2009, 121, 5556 –5559

DOI: 10.1002/adsc.200900525

Copper-Catalyzed Efficient Multicomponent Reaction: Synthesisof Benzoxazoline-Amidine Derivatives

Yongjia Shang,a,* Xinwei He,a Jinsong Hu,a Jianwei Wu,a Min Zhang,a Shuyan Yu,a

and Qianqian Zhangaa Key Laboratory of Functional Molecular Solids, Ministry of Eudcation, Anhui Key Laboratory of Molecule-Based

Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, People�s Republic ofChinaFax: (+86)-553-386-9303; phone: (+86)-553-393-7138; e-mail : shyj@mail.ahnu.edu.cn

Received: July 28, 2009; Published online: October 28, 2009

Supporting information for this article is available on the WWW underhttp://dx.doi.org/10.1002/adsc.200900525.

Abstract: We have developed an efficient copper-cat-alyzed method for the synthesis of the benzoxazo-line-amidine derivatives. The protocol uses inexpen-sive copper(I) iodide as the catalyst, and furnishedthe expected product in good to excellent yields by athree-component reaction of sulfonyl azides, termi-nal alkynes and Schiffs� bases in terahydrofuran(THF) at room temperature for 8 h in the presence

of triethylamine. This novel synthetic protocol is se-lective, efficient and general. A plausible mechanismfor this process is proposed.

Keywords: alkynes; azides; benzoxazoline-amidinederivatives; copper catalysis; multicomponent reac-tion; phenolic Schiffs� bases

Introduction

Arylbenzoxazoline derivatives are an important classof compounds and provide a common heterocyclicscaffold. They exhibit a wide range of biological andmedicinal activities including anticancer, Gram-posi-tive antibacterial,[1] anti-HIV,[2] antibiotic,[3] antipara-sitic,[4] anti-inflamatory,[5] H2-antagonist, and elastaseinhibitor[6] properties. They are also fluorescentwhitening agents,[7] constituents of cyanine dyes,[8]

heat resistant fibers,[9] fluorescent materials,[10] opticalbrighteners,[11] metal-coordinated ligands,[12] and me-dicinally significant compounds.[13]

It was previously demonstrated that arylbenzoxazo-line derivatives can be obtained from 2-aminophenolsvia heterocyclization reactions catalyzed by strongacid.[14] Another method for the synthesis of arylben-zoxazoline derivatives is the oxidative cyclization ofSchiffs� bases.[15] The oxidants could be PhI ACHTUNGTRENNUNG(OAc)2,

[16]

NiO2,[17] Ba ACHTUNGTRENNUNG(MnO4)2,

[18] DDQ,[15b] Mn ACHTUNGTRENNUNG(OAc)2,[19]

Pb ACHTUNGTRENNUNG(OAc)2,[20] and ThClO4.

[21] Other methods for syn-thesis of arylbenzoxazoline derivatives involving Ru-catalyzed hydroamination of diynes[22] and CuI-cata-lyzed[23] cyclization of ortho-haloanilides have beenreported. However, most of these methodologiessuffer from lengthy procedures that require excess

amounts of reagents such as PPTS/PPA, p-TsOH,SOCl2/HF, PPh3-DEAD, metal catalyst/oxidizingagents, etc, and harsh reaction conditions such asstrong acid, high temperature. As a result, a general,practical and efficient protocol for the synthesis ofbenzoxazoline derivatives is of interest and remains achallenging project.

Many MCRs (multicomponent reactions) show ad-vantages in atomic economy, environmental friend-ness, simplified steps, and efficient use of resources.[24]

The synthetic utility of the generated molecules fromcopper-catalyzed three-component reactions has beenextensively investigated in various areas. Recently,CuI-catalyzed[25] MCRs concerning sulfonyl azidesand alkynes have drawn special interest. Changet al.[26] and Wang�s group[27] have reported the effi-cient copper-catalyzed multicomponent reactions ofsulfonyl azides, terminal alkynes and amines, water,alcohol, imines, salicylaldehyde or aziridine to affordN-sulfonylamidines, hydrated amides, N-sulfonylazeti-din-2-imines, iminocoumarins, and 5-arylidene-2-imino-3-pyrrolines efficiently.

Amidines are prominent structural motifs in numer-ous bioactive natural products.[28] We accordingly en-visioned that amidines containing benzoxazoline moi-eties may afford unique biological activities, which

Adv. Synth. Catal. 2009, 351, 2709 – 2713 � 2009 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim 2709

FULL PAPERS

DOI: 10.1002/chem.200802561

Porous Co3O4 Nanosheets with Extraordinarily High Discharge Capacity forLithium Batteries

Fangming Zhan, Baoyou Geng,* and Yijun Guo[a]

IntroductionLi-ion batteries, owing to their high energy density, lightweight, and long cycle life, have become widely used forconsumer electronic devices. Over the past few decades, aworldwide effort has been made to search for alternativeanode materials for lithium batteries that will improve theirenergy density and safety.[1] It has been found that 3D tran-sition-metal oxides such as nickel oxide, cobalt oxide, andiron oxide exhibit reversible capacities about three timeslarger than those of graphite (372 mAhg�1) at a relativelylow potential, which has greatly spurred the rapid develop-ment in this field.[2] Among them, cobalt oxides (Co3O4 andCoO) have shown the highest capacity (700 mAhg�1) andbest cycle performance (93.4% of initial capacity was re-tained after 100 cycles) when compared with nickel oxide(NiO) and iron oxides (Fe2O3 and Fe3O4).

[3] In recent years,nanostructured materials have attracted great interest in the

application of anode or cathode materials for lithium batter-ies because of their high surface-to-volume ratio and shortpath length for Li+ transport.[4] As a result, it is believedthat the Co3O4 nanomaterials can lead to superior Li-batteryperformance.

Nanostructured Co3O4 is of great importance in many ap-plications; in particular, it has recently attracted intensiveresearch efforts in lithium-ion batteries since the seminalwork in this area by Tarascon and co-workers in 2000.[5]

Prompted by these interests, many Co3O4 nanostructures, in-cluding nanocubes, nanowires, nanowalls, nanotubes, and or-dered mesoporous structures have been synthesized bymeans of various routes.[6–11] As an example, virus-templatedCo3O4 nanowires have recently been demonstrated as an im-proved electrode for lithium-ion batteries.[12] However, de-spite their ultrahigh capacity, the practical use of Co3O4 asan anode electrode for lithium-ion batteries is still largelyhindered by large initial irreversible loss and poor capacityretention over extended cycling.[13–16]

In this paper, we describe a solid-state crystal reconstruc-tion route that opens the way for synthesis of porous, single-crystal Co3O4 nanosheets without the need for a template orstructure-directing agent. Unlike conventional approachesfor preparing porous inorganic structures, which utilize soft(e.g., surfactants, hydrogel matrices, block copolymers)[17] orhard (e.g., preformed porous structures) templates,[8] in thepresent strategy the porous structure is generated due to in-

Abstract: In this work, we report thesimple solid-state formation of porousCo3O4 with a hexagonal sheetlike struc-ture. The synthesis is based on con-trolled thermal oxidative decomposi-tion and recrystallization of precursorCo(OH)2 hexagonal nanosheets. Afterthermal treatment, the hexagonalsheetlike morphology can be complete-ly preserved, despite the fact that thereis a volume contraction accompanyingthe process: Co(OH)2!Co3O4. Be-

cause of the intrinsic crystal contrac-tion, a highly porous structure of theproduct is simultaneously created. Im-portantly, when evaluated as electrodematerials for lithium-ion batteries, theas-prepared porous Co3O4 nanosheetsexhibit superior Li-battery perfor-

mance with good cycle life and high ca-pacity (1450 mAhg�1) due to theirporous sheetlike structure and smallsize. As far as we know, the perfor-mance of the Co3O4-based anode mate-rials for lithium batteries presentedhere is the best up to now. Consideringthe improved performance and cost-ef-fective synthesis, the as-preparedporous Co3O4 nanosheets might besuitable as anode electrodes for next-generation lithium-ion batteries.

Keywords: batteries · cobalt oxides ·electrochemistry · lithium ·nanostructures

[a] F. Zhan, Dr. B. Geng, Y. GuoCollege of Chemistry and Materials ScienceAnhui Key Laboratory of Functional Molecular SolidsAnhui Laboratory of Molecular-Based MaterialsAnhui Normal University, Wuhu, 241000 (P.R. China)Fax: (+86)553-3869303E-mail : bygeng@mail.ahnu.edu.cn

Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/chem.200802561.

Chem. Eur. J. 2009, 15, 6169 – 6174 � 2009 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim 6169

FULL PAPER

Rapid construction of five contiguous stereocenters in a multi-cascadereactionw

Yimin Hu,* Ying Ouyang, Yuan Qu, Qiong Hu and Hao Yao

Received (in College Park, MD, USA) 14th January 2009, Accepted 12th June 2009

First published as an Advance Article on the web 6th July 2009

DOI: 10.1039/b900770a

The first example of a palladium-catalyzed multi-cascade

reaction by simple cycloenes with aryl halides in a single

operation to furnish five-contiguous-stereocenter hydro-

naphthoindolones is described.

Discovery of efficient methods to construct complex molecules

with multiple stereogenic centers in excellent regio-, diastereo-

and enantioselectivity continue to be an important goal for

both academic and industrial researchers.1 Multi-cascade

reactions which allow the formation of many C–C bonds

and stereogenic centers in a one-pot manner are useful for

the synthesis of natural products and synthetic building

blocks.2 These processes are usually clean as they generate

less waste by minimizing isolation of intermediates in the

multistep synthesis of complex molecular targets.3 Therefore,

the design of new catalytic and stereoselective cascade reactions

is a continuing challenge at the forefront of synthetic

chemistry.4 Recently, Takahashi5 developed Pd-mediated

spirocyclization leading to a formal synthesis of dimethyl

gloiosiphone and Mulzer6 employed the Vollhardt cyclization

in an enantioselective synthesis of pasteurestin A. In a

particularly straightforward approach, Enquist and co-workers

have reported the total synthesis of the cyathin diterpenoid

(�)-cyanthiwigin F by means of double catalytic enantio-

selective alkylation.7 These molecules have interesting bio-

logical and pharmaceutical properties, and thus much effort

has been made towards their synthesis.8,9 As a result of our

interest in the development of palladium-catalyzed processes

and directly obtaining physiologically active substances in a

single operation,10 we report herein the palladium-catalyzed

reactions of N-benzyl-N-(cyclohex-2-enyl)cinnamamide (a),

N-benzyl-3-(4-chlorophenyl)-N-cyclohexenylacrylamide (b),

N-benzyl-N-(cyclohex-2-enyl)-3-(4-methoxyphenyl)acrylamide

(c), N-cyclohexenyl-N-phenylcinnamamide (d), N-benzyl-N-

(cyclopent-2-enyl)cinnamamide (e) and N-benzyl-N-(cyclooct-

2-enyl)cinnamamide (f) (Scheme 1) with different aryl halides,

which provide a direct, efficient and economic methodology

for the construction of more stereocentres, non-racemic

carbocycles and heterocycles through both C–C bond

coupling and C–H bond activation. A survey of the reaction

conditions using N-benzyl-N-(cyclohex-2-enyl)cinnamamide

(a) and ethyl 4-bromobenzoate as a test experiment was

performed (Table 1).

In the test experiment, reaction of a with ethyl 4-bromo-

benzoate in N,N-dimethylformamide (DMF) in the presence of

a catalytic amount of Pd(OAc)2 produced the ethyl 4-benzyl-

5-oxo-6-phenyl-1,2,3,3a,3a1,4,5,5a,6,10b-decahydronaphtho-

[3,2,1-cd]indole-9-carboxylate aa in 84% yield at 150 1C for 18 h.

Altering the experimental conditions indicated that the output

of the multi-cascade reaction producing the product aa was

greatly affected by the reaction temperature (Table 1, entries 1–4),

the additive base (Table 1, entries 5, 10, 11), the catalytic

system (Table 1, entries 1–3, 11, 12), and the solvent (Table 1,

entries 1–3). Thus, the following standard reaction conditions

were selected for carrying out the following studies: dienes

(1 equiv.) reacted with different aryl halides (1.2 equiv.) in the

presence of 2 mol% of palladium(II) catalyst and 4 mol% of

Ph3P with nBu3N (2 equiv.) as an additive in DMF at 150 1C.In order to probe the scope and limitations of this novel

fused cyclization reaction, a range of substituted aryl halides

and substrates were examined. It was found that the outputs of

the reactions worked well with a variety of dienes (1 equiv.)

(a–d, f) and different aryl halides (1.2 equiv). As shown in

Table 2, this novel catalytic multi-cascade process can be

applied to the construction of functionalized fused hetero-

cycles in a single operation via the Heck reaction and inter- or

intramolecular C–H bond activation.

A variety of hydronaphthoindolones were readily isolated in

good to excellent yields (Table 2, entries 1–14, 17–20) when

aryl halides with electron-withdrawing groups (ethoxy-

carbonyl, ketyl, chloro, sulfonyl and cyano) were employed.

However, the corresponding fused heterocyclic compounds

could not be isolated if the aryl halides had electron-donating

substituents on the benzene ring, and a considerable amount

of intramolecular fused products (for example, Fig. 1, h) were

obtained when 4-bromotoluene, 2-bromotoluene or 1-bromo-

4-methoxybenzene were used, indicating the electronic effects

Scheme 1

Laboratory of Functional Molecular Solids, Ministry of Education,Anhui Key Laboratory of Molecular-Based Materials, School ofChemistry and Materials Science, Anhui Normal University, Wuhu,Anhui 241000, China. E-mail: yiminhu@mail.ahnu.edu.cn;Fax: +86 553 388 3517; Tel: +86 553 386 9310w Electronic supplementary information (ESI) available: Experimentalprocedures and characterization of all new compounds. CCDC715801–715805. For ESI and crystallographic data in CIF or otherelectronic format see DOI: 10.1039/b900770a

This journal is �c The Royal Society of Chemistry 2009 Chem. Commun., 2009, 4575–4577 | 4575

COMMUNICATION www.rsc.org/chemcomm | ChemComm

Copper oxide nanoarray based on the substrate of Cu applied for the chemicalsensor of hydrazine detection

Guangfeng Wang, Aixia Gu, Wen Wang, Yan Wei, Jingjing Wu, Guozhong Wang, Xiaojun Zhang *, Bin Fang *

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids and Anhui Key Laboratory of Chem-Biosensing, Anhui Normal University,No. 1 Beijing East Road, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 3 December 2008Received in revised form 11 December 2008Accepted 17 December 2008Available online 3 January 2009

Keywords:CuO nanoarrayCu substrateHydrazineDetection

a b s t r a c t

This communication reports on a novel amperometric hydrazine sensor of CuO nanoarray based on a Cusubstrate. Copper oxide nanoarray was directly grown on Cu substrates using a one-step facile hydrother-mal method and was characterized using scanning electron microscopy and X-ray powder diffraction.The electrochemical study has shown that the CuO nanoarray exhibits higher catalytic effect on thehydrazine than the normal CuO nanoparticles. This may be attributed to the special structure of thenanomaterials esp. the substrate of the electric Cu. And the amperometric response showed that theCuO nanoarray modified glassy carbon electrode has a low detection and a high sensitivity for hydrazine.

� 2008 Elsevier B.V. All rights reserved.

1. Introduction

Hydrazine is widely used as a fuel in rocket propulsion systems,also pesticides, blowing agents, pharmaceutical intermediates,photographic chemical and so on [1]. Symptoms of acute exposureto high levels of hydrazine include irritation of eyes, nose, andthroat, temporary blindness, dizziness, nausea, pulmonary edemaand coma in humans. Acute exposure can also damage the liver,kidneys, and central nervous system in humans [2]. All the abovemake their detection and quantitation problems of considerableanalytical interest. Among several techniques, electrochemicaltechniques offer the opportunity for portable, economical, sensi-tive and rapid methodologies for the determination of hydrazine[3]. The anodic oxidation of hydrazine happens on noble metalsor carbon electrodes, but they are all accompanied with large over-potentials. Therefore various materials have been applied to solvethe problem, such as metal complexes of phthalocyanine [4,5], por-phyrins [6,7], hexacyanoferrates [8], over oxidized polypyrrole [9]and some organic substances with an o-hydroquinone or hydro-quinone structure [10,11]. Recently, the nanoparticles have beenused to enhance the electron-transfer rate and to reduce the over-potential for the oxidation of hydrazine, due to the exotic proper-ties of nanostructures [12,13].

CuO is a p-type semiconducting material (energy gap of�1.4 eV) that exhibits photoconductive, photovoltaic and catalytic

properties [14]. Because the properties of materials at nanoscaleregime are strongly influenced by their shape and dimensionalconstraint, it is expected that the synthesis of the CuO into nano-structured materials, which could enhance its intrinsic characteris-tics in existing application. Recently some high dimensionalnanostructures of CuO have been prepared by material scientistsand attaching these nanostructures onto certain solid supporthas attracted much attention in order to make this kind of nano-structure viable in the special applications [15]. And new charac-teristics acquired from these nanostructures might be affected bythe bulk properties substrate. In order to attain better electric char-acter, we prepared nanostructures of 3D CuO based on Cu sub-strate. However, hitherto, very few reports on the preparation of3D CuO nanostructures based on a Cu substrate and the use forthe fabrication of an amperometric sensor have been available inthe literature. Especially, the use of CuO nanostructures for the fab-rication of an electrochemical hydrazine sensor has not been re-ported yet in the literature.

Here we present, for the first time, the growth of a large-scalevertical array of CuO nanoarray on the surface of a Cu structureand an amperometric sensor based on the CuO nanoarray for theeffective detection of hydrazine. The field-emission scanning elec-tron microscopy (FESEM) analysis of the samples confirms the for-mation of a large-scale vertical array of small (diameter ca. 10 nmand length >100 nm) nano-CuO on the surface of copper structure.The result showed the prepared CuO nanoarray could catalyzehydrazine effectively and the result is better than that of simpleCuO nanoparticles without the Cu substrate. The fabricatedhydrazine sensor showed a high sensitivity of 29.78 lA lM�1 with

1388-2481/$ - see front matter � 2008 Elsevier B.V. All rights reserved.doi:10.1016/j.elecom.2008.12.061

* Corresponding authors. Tel./fax: +86 (0)553 3869303.E-mail addresses: zhangxiaojun173@yahoo.co.cn (X. Zhang), wangyuz@mail.

ahnu.edu.cn (B. Fang).

Electrochemistry Communications 11 (2009) 631–634

Contents lists available at ScienceDirect

Electrochemistry Communications

journal homepage: www.elsevier .com/locate /e lecom

Letters

Magnetic Chitosan Nanocomposites: A Useful Recyclable Tool forHeavy Metal Ion Removal

Xiaowang Liu,*,† Qiyan Hu,‡ Zhen Fang,† Xiaojun Zhang,† and Beibei Zhang†

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,Anhui Normal UniVersity, Wuhu 241000, China, and Department of Pharmacy, Wannan Medical College,

Wuhu 241002, China

ReceiVed August 23, 2008. ReVised Manuscript ReceiVed NoVember 1, 2008

Magnetic chitosan nanocomposites have been synthesized on the basis of amine-functionalized magnetite nanoparticles.These nanocomposites can be removed conveniently from water with the help of an external magnet because of theirexceptional properties. The nanocomposites were applied to remove heavy metal ions from water because chitosanthat is inactive on the surface of the magnetic nanoparticles is coordinated with them. The interaction between chitosanand heavy metal ions is reversible, which means that those ions can be removed from chitosan in weak acidic deionizedwater with the assistance of ultrasound radiation. On the basis of the reasons referred to above, synthesized magneticchitosan nanocomposites were used as a useful recyclable tool for heavy metal ion removal. This work provides apotential platform for developing a unique route for heavy metal ion removal from wastewater.

1. Introduction

It is well known that heavy metal ions such as Pb2+, Cd2+,Hg2+, Ni2+, and Cu2+ can cause severe health problems in animalsand human beings because they may specifically bind to proteins,nucleic acids, and small metabolites in living organisms. Thiscauses either the alteration or loss of biological function andmay perturb the homeostatic control of essential metals.1-3 Forexample, Pb2+ can obstruct heme biosynthesis, inhibit severalzinc enzymes, interact with nucleic acids and tRNA to affectprotein synthesis, and accumulate in the apatite structure of thebone.4-6 However, these toxic metal ions commonly exist inprocess waste streams from mining operations, metal-platingfacilities, power generation facilities, electronic device manu-facturing units, and tanneries.7 Thus, the removal of such toxicmetal ions from wastewater is a crucial issue. Several methods,including chemical precipitation, ion exchange, liquid-liquidextraction, resins, cementation, and electrodialysis have beendeveloped for the removal of the above heavy metal ions fromindustrial wastewater. Each method has been found to be limitedby cost, complexity, and efficiency as well as by secondary waste.Using low-cost biosorbents such as agricultural wastes, claymaterials, biomass, and seafood processing wastes may be analternative wastewater technology because they are inexpensive

and capable of removing trace levels of heavy metal ions.8,9

However, to improve their absorption capacity and enhance theseparation rate, the design of and exploration of novel adsorbentsare still necessary. Recently, nanometer-sized hierarchicallystructured metal oxides have been used for wastewater treatmentand have shown remarkable potential because those materialshave large surface areas.10-12 From a practical point of view,there is a major drawback to the application of such nanomaterialsfor treating wastewater. Because the treatment of wastewater isusually conducted in a suspension of those nanostructures, itrequires an additional separation step to remove such nanoma-terials from solution. Removing such fine materials, especiallynanostructures, from a large volume of water involves furtherexpense. Furthermore, most studies have shown that thosenanostructures have excellent adsorption capacities for toxic metalions in water in the first cycle. The absorption ability of thesenanomaterials in succeeding cycles is unclear, which is veryimportant in practical applications. The recent successful synthesisof monodisperse magnetic nanoparticles, particularly iron oxidenanoparticles, provides a convenient tool for exploring magneticseparation techniques because of their specific characteristics.They have the capability to treat large amounts of wastewaterwithin a short time and can be conveniently separated fromwastewater; moreover, they could be tailored by using func-tionalized polymers, novel molecules, or inorganic materials toimpart surface reactivity.13,14 For example, Xu and co-workershave shown that the bisphosphonate derivative modifies the

* To whom correspondence should be addressed. E-mail: xwliu601@yahoo.com.cn.

† Anhui Normal University.‡ Wannan Medical College.(1) Silver, S. Microbes EnViron. 1998, 13, 177.(2) Martin, R. B. Met. Ions Biol. Syst. 1986, 20, 21.(3) Martin, R. B. In Handbook on Toxicity of Inorganic Compounds; Seiler,

H. G., Sigel, H., Eds.; Marcel Dekker: New York, 1988; Chapter 2, p 9.(4) Kazakov, S. A.; Hecht, S. M. In Encyclopedia of Inorganic Chemistry;

King, R. B., Ed.; Wiley Interscience: Chichester, U.K., 1994; Vol. 5, p 2697.(5) Eichhorn, G. L. In Inorganic Biochemistry; Eichhorn, G. L., Ed.; Elsevier:

Amsterdam, 1973; Vol. 2, p 1191.(6) Izatt, R. M.; Christensen, J. J.; Rytting, J. H. Chem. ReV. 1971, 71, 439.(7) Boddu, V. M.; Abburi, K.; Talbott, J. L.; Smith, E. D. EnViron. Sci. Technol.

2003, 37, 4449.

(8) Guibal, E. Sep. Purif. Technol. 2004, 38, 43.(9) Babel, S.; Kurniawan, T. A. J. Hazard. Mater. 2003, B97, 219.(10) Zhong, L. S.; Hu, J. S.; Liang, H. P.; Cao, A. M.; Song, W. G.; Wan, L. J.

AdV. Mater. 2006, 18, 2426.(11) Zhong, L. S.; Hu, J. S.; Cao, A. M.; Liu, Q.; Song, W. G.; Wan, L. J.

Chem. Mater. 2007, 19, 1648.(12) Hu, J.-S.; Zhong, L.-S.; Song, W.-G.; Wan, L.-J. AdV. Mater. 2008, 20,

2977.(13) Rocher, V.; Siaugue, J. M.; Cabuil, V.; Bee, A. Water Res. 2008, 42,

1290.(14) Banerjee, S. S.; Chen, D. H. J. Hazard. Mater. 2007, 147, 792.

3Langmuir 2009, 25, 3-8

10.1021/la802754t CCC: $40.75 © 2009 American Chemical SocietyPublished on Web 11/25/2008

7244 DOI: 10.1021/la901407d Langmuir 2009, 25(13), 7244–7248Published on Web 06/09/2009

pubs.acs.org/Langmuir

© 2009 American Chemical Society

Carboxyl Enriched Monodisperse Porous Fe3O4 Nanoparticles withExtraordinary Sustained-Release Property

Xiaowang Liu,*,† Qiyan Hu,‡ Zhen Fang,† Qiong Wu,† and Qiubo Xie†

†College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,Anhui Normal University, Wuhu 241000, China, and ‡Department of Pharmacy, Wannan Medical College,

Wuhu 241002, China

Received April 21, 2009. Revised Manuscript Received May 30, 2009

Carboxyl-enriched monodisperse porous Fe3O4 nanoparticles with diameters of about 85-nm have been synthesizedvia a simple hydrothermal method. The porous structure of the product is confirmed further by transmission electronmicroscopy (TEM) observation and nitrogen sorption measurement with a Brunauer-Emmett-Teller (BET) surfacearea about 36.61 m2/g. An IR spectrum of the sample indentifies that abundant caboxylate groups are formed on thesurface of the nanoparticles as well as the pore surface. Because of the confined effect of the nanochannels in thenanoparticles and carboxyl-functionalized Fe3O4 nanoparticles, and the strong interaction between ibuprofen andCOO-, as-prepared porous nanoparticles show a more extraordinary sustained-release property than that of hollowsilica nanoparticles in vitro. This result suggests that as-prepared porous nanoparticles can also be used for the targeteddelivery of other aromatic acid drugs.

Introduction

Recently, there has been an increasing amount of activity tofabricate nano/micrometer-scale carriers and a growing demandfor their use in sophisticated applications in the life and materialsscience.1 Generally, nano/microcarriers would be inexpensivematerials with simple methods to fabricate, and have highmedicine loading. A series of nano/microstructures, such asCaCO3 microparticles, porous hollow nanostructured hydroxya-patite and calcium silicatehave, amphiphilic TiO2 nanotubearrays, calcium phosphate nanoparticles, and mesoporous silicahave been applied as drug carriers with sustained-release prop-erty.2 Among these materials, amorphous mesoporous silica isone of the most promising candidates for the usage of drugcarriers because of its nontoxic nature, tunable diameter, and veryhigh specific surface.3 However, it is difficult to guide pure silicamaterials to target organs or locations in the body as drugcarriers. Nanocomposites with the advantages of mesoporoussilica and magnetic nanoparticles are feasible to be applied in

targeted delivery. Several strategies have been successfully used tosynthesize such nanocomposites, and the results demonstrate thatas-prepared nanocomposites have a good sustained-release prop-erty.4 However, it is worth noting that as-prepared nanocompo-sites usually have a diameter higher than 200 nm, which meansthat such nanocomposites are impossible to inject into the bodyintravenously as drug carriers because particles with such size areeasily sequestered by the spleen and eventually removed by thecells of the phagocyte system, resulting in decreased bloodcirculation time.5 Magnetic nanoparticles, especially iron oxidenanocrystals, have been widely studied for various biomedicalapplications such as targeted drug delivery, cell sorting, contrastagents for magnetic resonance imaging, and hyperthermia,because of their fascinating properties,6 including biocompatibil-ity and stability in physiological conditions and size-dependentmagnetic properties.7 In this letter, carboxyl-enriched monodis-perse porousFe3O4 nanoparticleswith diameters less than 100 nmwere synthesized using a facile hydrothermal method. Because ofabundant carboxyl on the pore of the nanochannels and particlesurface of the products, they were dispersed well in aqueoussolution, and the obtained colloid solution could exist at least forseveral weeks. Ibuprofen, a kind of aromatic acid drug with goodpharmacological activity, was chosen as a model drug toinvestigate the in vitro release property of the prepared carboxyl-enriched monodisperse porous Fe3O4 nanoparticles, which have

*Towhom correspondence should be addressed. E-mail: xwliu601@yahoo.com.cn.(1) Lvov, Y.M.; Shchukin, D.G.;M€ohwald, H.; Price, R. R.ACSNano 2008, 2,

814.(2) Volodkin, D. V.; Larionova, N. I.; Sukhorukov, G. B. Biomacromolecules

2004, 5, 1962. Ma, M.-Y.; Zhu, Y.-J.; Li, L.; Cao, S.-W. J. Mater. Chem. 2008, 18,2722. Song, Y.-Y.; Schmidt-Stein, F.; Bauer, S.; Schmuki, P. J. Am. Chem. Soc.2009, 131, 4230. Morgan, T. T.; Muddana, H. S.; Altinolu, E.; Rouse, S. M.;Tabakovi, A.; Tabouillot, T.; Russin, T. J.; Shanmugavelandy, S. S.; Butler, P. J.;Eklund, P. C.; Yun, J. K.; Kester, M.; Adair, J. H.Nano Lett. 2008, 8, 4108. Yang,J.; Lee, J.; Kang, J.; Lee, K.; Suh, J.-S.; Yoon, H.-G.; Huh, Y.-M.; Haam, S.Langmuir 2008, 24, 3417.(3) Lu, J.; Liong, M.; Zink, J. I.; Tamanoi, F. Small 2007, 3, 1341. Zhu, Y.; Shi,

J.; Shen,W.; Dong, X.; Feng, J.; Ruan, M.; Li, Y.Angew. Chem., Int. Ed. 2005, 44,5083. Mal, N. K.; Fujiwara, M.; Tanaka, Y. Nature 2003, 421, 350. Munoz, B.;Ramila, A.; Pariente, J. P.; Diaz, I.; Vallet-Regi, M. Chem. Mater. 2003, 15, 500.Giri, S.; Trewyn, B. G.; Stellmaker, M. P.; Lin, V. S.-Y. Angew. Chem., Int. Ed.2005, 44, 5038. Trewyn, B. G.; Slowing, I. I.; Giri, S.; Chen, H.-T.; Lin, V. S.-Y.Acc. Chem. Res. 2007, 40, 846.(4) Zhao,W.; Chen, H.; Li, Y.; Li, L.; Lang,M.; Shi, J.Adv. Funct.Mater. 2008,

18, 2780. Zhao, W.; Gu, J.; Zhang, L.; Chen, H.; Shi, J. J. Am. Chem. Soc. 2005,127, 8916. Hu, S.-H.; Liu, T.-Y.; Huang, H.-Y.; Liu, D.-M.; Chen, S.-Y. Langmuir2008, 24, 239.Huang, S.; Fan, Y.; Cheng, Z.; Kong,D.; Yang, P.; Quan, Z.; Zhang,C.; Lin, J. J. Phys. Chem. C 2009, 113, 1775.

(5) Laurent, S.; Forge, D.; Port, M.; Roch, A.; Robic, C.; Elst, L. V.; Muller, R.N.Chem. Rev. 2008, 108, 2064. Berry, C. C.; Curtis, A. S.G. J. Phys. D:Appl. Phys.2003, 36, R198.

(6) Alexiou, C.; Arnold, W.; Klein, R. J.; Parak, F. G.; Hulin, P.; Bergemann,C.; Erhardt,W.;Wagenpfeil, S.; Lubbe, A. S.Cancer Res. 2000, 60, 6641. Artemov,D. J. Cell. Biochem. 2003, 90, 518. Ito, A.; Tanaka, K.; Kondo, K.; Shinkai, M.;Honda, H.; Matsumoto, K.; Saida, T.; Kobayashi, T. Cancer Sci. 2003, 94, 308.Alexiou, C.; Jurgons, R.; Schmid, R. J.; Bergemann, C.; Henke, J.; Erhardt, W.;Huenges, E.; Parak, F. J. Drug Target. 2003, 11, 139.

(7) Cengelli, F.; Maysinger, D.; Tschudi-Monnet, F.; Montet, X.; Corot, C.;Petri-Fink, A.; Hofmann, H.; Juillerat-Jeanneret, L. J. Pharmacol. Exp. Ther.2006, 318, 108. Petri-Fink, A.; Chastellain, M.; Juillerat-Jeanneret, L.; Ferrari, A.;Hofmann, H. Biomaterials 2005, 26, 2685. Brigger, I.; Dubernet, C.; Couvreur, P.Adv. Drug Delivery Rev. 2002, 54, 631. Wang, L.; Bao, J.; Wang, L.; Zhang, F.; Li,Y. Chem.;Eur. J. 2006, 12, 6341.

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DOI: 10.1021/jo901407h Published on Web 09/01/2009 J. Org. Chem. 2009, 74, 7525–7528 7525r 2009 American Chemical Society

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β-Formyl-BODIPYs from the Vilsmeier-HaackReaction

Lijuan Jiao,* Changjiang Yu, Jilong Li, Zhaoyun Wang,Min Wu, and Erhong Hao

Anhui Key Laboratory of Functional Molecular Solids,College of Chemistry and Material Science, and Anhui KeyLaboratory of Molecular Based Materials, Anhui Normal

University, Wuhu 241000, China

jiao421@mail.ahnu.edu.cn

Received July 2, 2009

A series of β-formyl-BODIPYs 2were synthesized in highyields from tetramethyl-BODIPYs 1 via the Vilsmeier-Haack reaction and were further functionalized using aKnoevenagel condensation to generate novel BODIPYs3 and 4.

Boradiazaindacenes, known as BODIPY dyes, arestrongly UV-absorbing small molecules with high fluores-cence quantum yields, sharp fluorescence emissions, highphotophysical stability, and low sensitivity to the polarityand pH of their environment.1,2 Their fluorescence profilescan be easily tuned by way of small modifications to the

structures. Consequently, these molecules have found wideapplications as fluorescent labels for DNA3 and proteins4

and have attracted renewed research interests2 in highly diversefields as labeling reagents,3-5 fluorescent switches,6 chemosen-sors,7,8 laser dyes,9 photosensitizers,10 energy transfer cas-settes,11 supramolecular fluorescent gels,12 and harvestingarrays.13 Currently, their further application is hampered bythe limited availability associated with synthetic limitations,especially for those compounds with extended conjugation.

BODIPY itself is intrinsically electron-rich and has severalpositions available for functional modification, but most ofthe functionalization methods are not straightforward.2

Among these, functionalization at the 8-(meso) position(Figure 1) is relatively easy compared with the pyrrolicpositions via the condensation of various aryl aldehydes(Lindsey’s method)14a or acyl chlorides with pyrroles;14

many functional groups such as ligands or biomoleculesare often introduced via this method. However, the mesosubstituents and the BODIPY chromophore are almostperpendicular to each other, resulting in poor electronicconjugation between the two moieties. Thus, functionaliza-tion at the pyrrolic positions is more desirable.2,15 Typicalapproaches include (1) de novo syntheses from appropriatelysubstituted pyrroles if accessible and (2) the direct introduc-tion of pyrrolic substituents to a ready-made partially un-substituted BODIPY chromophore;2 this latter method isefficient, and substitution can be performed at both R- andβ-positions of the chromophore (Figure 1). Methods avail-able for functionalization at the R-position include Knoeve-nagel condensations of 3,5-dimethyl-BODIPYs using arylaldehyde,16 nucleophilic substitutions,17a,b or organometalliccouplings18 of 3,5-dichloro-BODIPYs17a,b and analogues.17c

(1) Haugland, R. P. Handbook of fluorescent Probes and Research Che-micals, 6th ed.; Molecular Probes: Eugene, OR, 1996.

(2) (a) Loudet, A.; Burgess, K.Chem. Rev. 2007, 107, 4891. (b)Ulrich, G.;Ziessel, R.; Harriman, A. Angew. Chem., Int. Ed. 2008, 47, 1184. (c) Ziessel,R.; Ulrich, G.; Harriman, A. New J. Chem. 2007, 31, 496.

(3) Merino, E. J.; Weeks, K. M. J. Am. Chem. Soc. 2005, 127, 12766.(4) Bergstrom, F.; Hagglof, P.; Karolin, J.; Ny, T.; Johansson, L. B. A.

Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 12477.(5) (a) Li, Z.; Mintzer, E.; Bittman, R. J. Org. Chem. 2006, 71, 1718. (b)

Meng, Q.; Kim, D. H.; Bai, X.; Bi, L.; Turro, N. J.; Ju, J. J. Org. Chem. 2006,71, 3248. (c) Peters, C.; Billich, A.; Ghobrial, M.; Hoegenauer, K.; Ullrich,T.; Nussbaumer, P. J. Org. Chem. 2007, 72, 1842. (d) Li, Z.; Bittman, R.J. Org. Chem. 2007, 72, 8376.

(6) (a) Golovkova, T. A.; Kozlov, D. V.; Neckers, D. C. J. Org. Chem.2005, 70, 5545. (b) Coskun, A.; Deniz, E.; Akkaya, E. U. Org. Lett. 2005, 7,5187.

(7) (a) Coskun, A.; Akkaya, E.U. J. Am. Chem. Soc. 2005, 127, 10464. (b)Yamada, K.; Nomura, Y.; Citterio, D.; Iwasawa, N.; Suzuki, K. J. Am.Chem. Soc. 2005, 127, 6956. (c)Wu,Y.; Peng, X.; Guo, B.; Fan, J.; Zhang, Z.;Wang, J.; Cui, A.; Gao, Y. Org. Biomol. Chem. 2005, 3, 1387. (d) Krumova,K.; Oleynik, P.; Karam, P.; Cosa, G. J. Org. Chem. 2009, 74, 3641. (e)Baruah, M.; Qin, W.; Basari�c, N.; De Borggraeve, W. M.; Boens, N. J. Org.Chem. 2005, 70, 4152.

(8) (a) Zeng, L.; Miller, E. W.; Pralle, A.; Isacoff, E. Y.; Chang, C. J.J. Am. Chem. Soc. 2006, 128, 10. (b) Wang, J.; Qian, X. Org. Lett. 2006, 8,3721. (c) Yuan, M.; Zhou, W.; Liu, X.; Zhu, M.; Li, J.; Yin, X.; Zheng, H.;Zuo, Z.; Ouyang,C.; Liu,H.; Li, Y.; Zhu,D. J.Org.Chem. 2008, 73, 5008. (d)Atilgan, S.; Ozdemir, T.; Akkaya, E. U. Org. Lett. 2008, 10, 4065.

(9) (a) Arbeloa, T. L.; Arbeloa, F. L.; Arbeloa, I. L.; Garcia-Moreno, I.;Costela, A.; Sastre, R.; Amat-Guerri, F.Chem. Phys. Lett. 1999, 299, 315. (b)Mula, S.; Ray, A. K.; Banerjee, M.; Chaudhuri, T.; Dasgupta, K.;Chattopadhyay, S. J. Org. Chem. 2008, 73, 2146.

(10) Yogo, T.; Urano, Y.; Ishitsuka, Y.; Maniwa, F.; Nagano, T. J. Am.Chem. Soc. 2005, 127, 12162.

(11) (a) Ulrich, G.; Goeze, C.; Guardigli, M.; Roda, A.; Ziessel, R.Angew. Chem., Int. Ed. 2005, 44, 3694. (b) Loudet, A.; Bandichhor, R.;Wu, L.; Burgess, K. Tetrahedron 2008, 64, 3642. (c) Tan, K.; Jaquinod, L.;Paolesse, R.; Nardis, s.; Di Natale, C.; Di Carlo, A.; Prodi, L.; Montalti, M.;Zaccheroni, N.; Smith, K. M. Tetrahedron 2004, 60, 1099.

(12) Camere, F.; Bonardi, L.; Schmutz,M.; Ziessel, R. J. Am. Chem. Soc.2006, 128, 4548.

(13) (a) Li, F.; Yang, S. I.; Ciringh, Y. Z.; Seth, J.; Martin, C. H.; Singh,D. L.; Kim, D.; Birge, R. R.; Bocian, D. F.; Holten, D.; Lindsey, J. L. J. Am.Chem. Soc. 1998, 120, 10001. (b) Yilmaz, M. D.; Bozdemir, O. A; Akkaya,E. U.Org. Lett. 2006, 8, 2871. (c) Erten-Ela, S.; Yilmaz,M.D.; Icli, B.; Dede,Y.; Icli, S.; Akkaya, E. U. Org. Lett. 2008, 10, 3299.

(14) (a) Wagner, R. W.; Lindsey, J. S. Pure. Appl. Chem. 1996, 68, 1373.(b) Burghart, A.; Kim, H.; Welch, M. B.; Thoresen, L. H.; Reibenspies, J.;Burgess, K.; Bergstrom, F.; Johansson, L. B.A. J.Org. Chem. 1999, 64, 7813.(c) Chen, J.; Burghart, A.; Derecskei-Kovacs, A.; Burgess, K. J. Org. Chem.2000, 63, 2900.

(15) (a) Umezawa, K.; Nakamura, Y.; Makino, H.; Citterio, D.; Suzuki,K. J. Am. Chem. Soc. 2008, 130, 1550. (b) Rurack, K.; Kollmannsberger,M.;Daub, J. Angew. Chem., Int. Ed. 2001, 40, 385.

(16) Dost, Z.; Atilgan, S.; Akkaya, E. U. Tetrahedron 2006, 62, 8484.(17) (a) Rohand, T.; Qin, W.; Boens, N.; Dehaen, W. Chem. Commun.

2006, 266. (b) Li, L.; Nguyen, B.; Burgess, K.Bioorg.Med. Chem. Lett. 2008,18, 3112.

(18) (a) Rohand, T.; Qin, W.; Boens, N.; Dehaen, W. Eur. J. Org.Chem. 2006, 4658. (b) Lager, E.; Liu, J.; Aguilar-Aguilar, A.; Tang, B. Z.;Pe~na-Cabrera, E. J. Org. Chem. 2009, 74, 2053.

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Journal of Membrane Science 326 (2009) 145–152

Contents lists available at ScienceDirect

Journal of Membrane Science

journa l homepage: www.e lsev ier .com/ locate /memsci

Chain-length dependence of the antifouling characteristics of the

glycopolymer-modified polypropylene membrane in an SMBR

Jia-Shan Gu, Hai-Yin Yu ∗, Lei Huang, Zhao-Qi Tang, Wei Li, Jin Zhou, Meng-Gang Yan, Xian-Wen Wei

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, China

a r t i c l e i n f o

Article history:Received 16 May 2008

Received in revised form

23 September 2008

Accepted 24 September 2008

Available online 1 October 2008

Keywords:Antifouling characteristics

d-Gluconamidoethyl methacrylate

Photoinduced graft polymerization

Polypropylene microporous membrane

Surface modification

Submerged membrane-bioreactor

a b s t r a c t

Membrane-bioreactor processes have increased considerably in recent years. However, the natural dis-

advantages of common membrane materials, such as hydrophobic surface, cause membrane fouling and

cumber further extensive applications. In this work, hydrophilic surface modification of polypropylene

microporous membranes was carried out by the sequential photoinduced graft polymerization of d-

gluconamidoethyl methacrylate (GAMA) to meet the requirements of wastewater treatment and water

reclamation applications. The grafting density and grafting chain length were controlled independently

in the first and second step, respectively. Attenuated total reflection–Fourier transform infrared spec-

troscopy (FT-IR/ATR) and X-ray photoelectron spectroscopy (XPS) were employed to confirm the surface

modification on the membranes. Water contact angle was measured by the sessile drop method. Results

of FT-IR/ATR and XPS clearly indicated that GAMA was grafted on the membrane surface. It was found

that the grafting chain length increased reasonably with the increase of the UV irradiation time. Water

contact angle on the modified membrane decreased with the increase of the grafting chain length, and

showed a minimum value of 43.2◦, approximately 51.8◦ lower than that of the unmodified membrane. The

pure water fluxes for the modified membranes increased systematically with the increase of the grafting

chain length. The effect of the grafting chain length on the antifouling characteristics in a submerged

membrane-bioreactor for synthetic wastewater treatment was investigated. After continuous operation

in the submerged membrane-bioreactor for about 70 h, reduction from pure water flux was 90.7% for the

virgin PPHFMM, and ranged from 80.8 to 87.2% for the modified membranes, increasing with increasing

chain length. The flux of the virgin PPHFMM membrane after fouling and subsequent washing was 31.5% of

the pure water flux through the unfouled membrane; for the modified membranes this ranged from 27.8

to 16.3%, decreasing with increasing chain length. These results demonstrated that the antifouling char-

acteristics for the glucopolymer-modified membranes were improved with an increase in GAMA chain

length.

© 2008 Elsevier B.V. All rights reserved.

1. Introduction

In recent years, membrane-bioreactor (MBR), as a novel and

powerful technique for wastewater treatment and water reclama-

tion, has received tremendous attention due to the increasingly

shortage of water worldwide [1,2]. However, a frequently encoun-

tered bottleneck is serious membrane fouling [3–6].

The negative effects on membrane performance due to the

fouling are basically known. However, the actual mechanism of

the fouling, especially in an MBR system, is not well understood.

Because the MBR system includes living microorganisms and their

metabolites, the biomass biological characteristics and the physico-

∗ Corresponding author. Tel.: +86 553 5991165; fax: +86 553 3869303.

E-mail address: yhy456@mail.ahnu.edu.cn (H.-Y. Yu).

chemical properties of the suspension, change with time, the

fouling mechanism is more complex than that of any membrane

separation processes.

It has been widely accepted that the effective strategy to sup-

press membrane fouling especially is to increase hydrophilicity of

membrane surface by incorporating hydrophilic macromolecule

modifiers [7–9]. As a result, much work has been done to reduce

membrane fouling by modifying hydrophobic materials to rela-

tive hydrophilic. Different methods including physical coating and

chemical reacting have been employed to modify the membrane

surface [8,10].

Among them, the grafting of hydrophilic monomers on

the membrane surface shows some promises [11–13]. Using

hydrophilic materials, this technique can increase the hydrophilic-

ity of the membrane, resulting in the enhancement of membrane

performance properties while simultaneously reducing the foul-

0376-7388/$ – see front matter © 2008 Elsevier B.V. All rights reserved.

doi:10.1016/j.memsci.2008.09.043

Journal of Membrane Science 343 (2009) 82–89

Contents lists available at ScienceDirect

Journal of Membrane Science

journa l homepage: www.e lsev ier .com/ locate /memsci

Thermo- and pH-responsive polypropylene microporous membrane prepared by

the photoinduced RAFT-mediated graft copolymerization

Hai-Yin Yu ∗, Wei Li, Jin Zhou, Jia-Shan Gu, Lei Huang, Zhao-Qi Tang, Xian-Wen Wei

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, China

a r t i c l e i n f o

Article history:Received 1 November 2008

Received in revised form 6 July 2009

Accepted 7 July 2009

Available online 15 July 2009

Keywords:Membrane surface modification

Multi-sensitive membrane

Photoinduced graft polymerization

Polypropylene microporous membrane

Reversible addition–fragmentation chain

transfer radical polymerization

a b s t r a c t

Thermo- and pH-responsive polypropylene microporous membrane prepared by photoinduced reversible

addition–fragmentation chain transfer (RAFT) graft copolymerization of acrylic acid and N-isopropyl acry-

lamide by using dibenzyltrithiocarbonate as a RAFT agent. Attenuated total reflection-Fourier transform

infrared spectroscopy (ATR/FT-IR), X-ray photoelectron spectroscopy (XPS) and field emission scanning

electron microscopy (FE-SEM) were used to characterize the structural and morphological changes on

the membrane surface. Results of ATR/FT-IR and XPS clearly indicated that poly(acrylic acid) (PAAc) and

poly(N-isopropyl acrylamide) (PNIPAAm) were successfully grafted onto the membrane surface. The graft-

ing chain length of PAAc on the membrane surface increased with the increase of UV irradiation time, and

decreased with the increase of the concentration of chain transfer agent. The PAAc grafted membranes

containing macro-chain transfer agents, or the living membrane surfaces were further functionalized

via surface-initiated block copolymerization with N-isopropyl acrylamide in the presence of free radi-

cal initiator, 2,2′-azobisisobutyronitrile. It was found that PNIPAAm can be grafted onto the PAAc grafted

membrane surface. The results demonstrated that polymerization of AAc and NIPAAm by the RAFT method

could be accomplished under UV irradiation and the process possessing the living character. The PPMMs

with PAAc and PNIPAAm grafting chains exhibited both pH- and temperature-dependent permeability to

aqueous media.

© 2009 Elsevier B.V. All rights reserved.

1. Introduction

Graft polymerization of a functional monomer on membrane

surface offers an effective approach to incorporating new prop-

erties, while retaining the desirable properties of membrane.

Polypropylene microporous membrane (PPMM) possesses desir-

able performances, such as high void volumes, well-controlled

porosity, chemical inertness, good mechanical strength and low

cost [1]. However, PPMM lacks functional groups, which leads

to hydrophobicity, poor biocompatibility, and also no reactivity.

As a result, modification of polypropylene membrane to endow

Abbreviations: AAc/PAAc, acrylic acid/poly(acrylic acid); ATR/FT-IR, atten-

uated total reflection-Fourier transform infrared spectroscopy; AIBN, 2,2′-azobisisobutyronitrile; BP, benzophenone; DBTTC, dibenzyltrithiocarbonate; FE-

SEM, field emission scanning electron microscopy; LCST, lower critical solution

temperature; Macro-CAT, macro-chain transfer agent; MW, molecular weight;

NIPAAm/PNIPAAm, N-isopropyl acrylamide/poly(N-isopropyl acrylamide); PPMM,

polypropylene microporous membrane; RAFT, reversible addition–fragmentation

chain transfer radical polymerization; UV, ultraviolet; XPS, X-ray photoelectron

spectroscopy.∗ Corresponding author. Tel.: +86 553 5991165; fax: +86 553 3869303.

E-mail address: yhy456@mail.ahnu.edu.cn (H.-Y. Yu).

it with new functionalities is very important. Different meth-

ods have been employed to modify the membrane surface [2–6].

Those surface modification approaches, though very useful, are

most commonly accomplished via the free radical process. These

approaches offer somewhat limited opportunity for molecular

engineering and controllable design of the grafted chain on the

membrane surfaces, which is very essential to the membrane

performances.

Progress in polymer science makes it possible to produce

well-defined graft polymer chains with controlled lengths and spe-

cific chain architectures [7–11]. Reversible addition–fragmentation

chain transfer (RAFT)-mediated polymerization is a method for

achieving controlled free radical polymerization, it involves a

reversible addition–fragmentation cycle, in which transfer of

a thioester moiety between the active and dormant species

maintains the controlled character of the polymerization. It

offers many benefits over traditional free radical polymeriza-

tion, including the ability to control molecular weight and

polydispersity and to prepare block copolymers and other poly-

mers with complex architecture—materials that are not readily

synthesized by other methodologies. However, for the surface

modification of membranes, much work has been done to pre-

treat the membranes by plasma treatment, ozone treatment

0376-7388/$ – see front matter © 2009 Elsevier B.V. All rights reserved.

doi:10.1016/j.memsci.2009.07.012

Notes & Tips

A facile strategy for nonenzymatic glucose detection

Yinling Wang *, Dandan Zhang, Weiwei Zhang, Feng Gao, Lun Wang *

Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China

a r t i c l e i n f o

Article history:Received 2 October 2008Available online 11 November 2008

a b s t r a c t

Glassy carbon electrode modified with boron oxide nanoparticles supported on multiwall carbon nano-tubes was obtained via a facile approach. The as-prepared modified electrode exhibits excellent electro-catalytic activity toward the redox of glucose in pH 7.0 phosphate buffer solution. The electrochemicalresponse of the modified electrode to glucose shows a linear range of 1.5–260 lMwith a correlation coef-ficient of 0.9986 and the calculated detection limit is 0.8 lM at a signal-to-noise ratio of 3, which makes ituseful for developing the electrochemical determination of glucose concentrations without using glucoseoxidase at physiological pH.

� 2008 Elsevier Inc. All rights reserved.

The determination of glucose concentration is very importantin many fields [1,2]. For example, to date, clinical diabetes moni-toring has been mainly based on blood glucose measurements[2]. In recent years, a number of studies have been conducted todevelop new glucose detection methods. Some methods use theglucose oxidase and show excellent sensitivity and high selectiv-ity; however, there are still some disadvantages, such as low stabil-ity, high complexity, bad reproducibility, and poor oxygenlimitations [3–5]. Among them the most serious drawback is insuf-ficient stability originated from the intrinsic nature of the enzymes.Therefore, it would be most desirable to determine glucose con-centration without using enzymes. In this work, we explored thatboron oxide nanoparticles (BONPs)1 supported on multiwall carbonnanotube (MWCNT)-modified glassy carbon (GC) electrodes arepotentially suitable for electrochemical enzyme-free detection ofglucose.

GC electrode modified with the BONPs supported on MWCNTswas prepared as follows. First, dehydrated boric acid (white solid)was obtained by drying highly pure boric acid at 140 �C for 1 h inan oven. Then 10 g dehydrated boric acid, mixed with 2 g urea,was transferred to a muffle furnace, slowly heated up to 300 �C(10 �C /min), and kept at 300 �C for 30 min. After the heat treat-ment, the mixture was pulverized in an agate and the micro- andnanostructured boron oxide particles were collected.

Second, the boron oxide nanoparticles (1 mg/L) and acid-trea-ted multiwall carbon nanotubes (1 mg/L) [6] were added to DMF

(10 mL). The mixture was immersed in a laboratory sonicationbath at room temperature for 12 h. Fig. 1 shows the high-resolu-tion transmission electron microscopy (HRTEM) images ofMWCNTs before (Fig. 1A) and after (Fig. 1B) treatment by BONPsin DMF. As seen in Fig. 1B, many BONPs were coated on theMWCNT surface.

Third, a GC electrode was polished with alumina powder (0.3,0.1, and 0.05 lm, respectively) on fine abrasive paper and soni-cated in acetone and triple-distilled water (each for 10 min). Theelectrode was rinsed with triple-distilled water and finally im-mersed into 0.1 M HClO4 solution. Five cyclic voltammograms ofthe polished glassy carbon electrode was recorded in a range of–0.2 to 1.8 V (vs Ag/AgCl) at a scan rate of 50 mV/s to verify thata clean and reproducible surface was obtained.

Finally, 10 lL of the suspension from the previous step wasspread on the surface of the pretreated GC electrode and the mod-ified electrode was washed with triple-distilled water severaltimes to remove the larger boron oxide particles that could notbe immobilized on the MWCNT surface stably. The as-preparedmodified electrode was air-dried at room temperature.

The electrocatalytic properties of the modified electrode to-ward the redox of glucose were investigated by cyclic voltamme-try (CV). As shown in Fig. 2 (curve a), no peaks were observed forthe MWCNT/GC electrode in a 0.1 mol/L pH 7.0 phosphate buffersolution (PBS) containing 20 lM glucose. However, the BONP/MWCNT/GC electrode gave a pair of stable and well-defined re-dox peaks with the apparent formal peak potential [7] of0.122 V and peak-to-peak separation of 37 mV (curve c) [8], sug-gesting a two-electron transfer. This voltammetric behavior ofglucose cannot be observed with other electrodes [3]. Simulta-neously, the effect of the quiet time on the redox peak currents(Ip) of glucose has been studied by CV at the modified electrode.The cyclic voltammograms indicate that the redox peak currents

0003-2697/$ - see front matter � 2008 Elsevier Inc. All rights reserved.doi:10.1016/j.ab.2008.11.004

* Corresponding authors. Fax: +86 553 3869303.E-mail addresses: wangyl@mail.ahnu.edu.cn (Y. Wang), wanglun@mail.ahnu.

edu.cn (L. Wang).1 Abbreviations used: BONPs, boron oxide nanoparticles; CV, cyclic voltammetry;

DPV, differential pulse voltammetry; GC, glassy carbon; MWCNTs, multiwall carbonnanotubes; PBS, phosphate buffer solution.

Analytical Biochemistry 385 (2009) 184–186

Contents lists available at ScienceDirect

Analytical Biochemistry

journal homepage: www.elsevier .com/ locate /yabio

Electrochimica Acta 55 (2009) 178–182

Contents lists available at ScienceDirect

Electrochimica Acta

journa l homepage: www.e lsev ier .com/ locate /e lec tac ta

A novel hydrazine electrochemical sensor based on a carbon nanotube-wired

ZnO nanoflower-modified electrode

Bin Fang ∗, Cuihong Zhang, Wei Zhang, Guangfeng Wang

Anhui Key Laboratory of Chemo-Biosensor, College of Chemistry and Materials Science, Anhui Normal University, Beijing East Road, No. 1, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 11 June 2009

Received in revised form 12 August 2009

Accepted 21 August 2009

Available online 31 August 2009

Keywords:MWCNTs

ZnO

Modified electrode

Electrocatalysis

Hydrazine

a b s t r a c t

ZnO nanoflowers were synthesized by a simple process (ammonia-evaporation-induced synthetic

method) and were applied to the hydrazine electrochemical sensor. The prepared material was char-

acterized by means of scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) and was

then immobilized onto the surface of a glassy carbon electrode (GCE) via multi-walled carbon nanotubes

(MWCNTs) to obtain ZnO/MWCNTs/GCE. The potential utility of the constructed electrodes was demon-

strated by applying them to the analytical determination of hydrazine concentration. An optimized limit

of detection of 0.18 �M was obtained at a signal-to-noise ratio of 3 and with a fast response time (within

3 s). Additionally, the ZnO/MWCNTs/GCE exhibited a wide linear range from 0.6 to 250 �M and higher

sensitivity for hydrazine than did the ZnO modified electrode without immobilization of MWCNTs.

© 2009 Elsevier Ltd. All rights reserved.

1. Introduction

Hydrazine (N2H4) is widely used in industrial applications,

such as corrosion inhibitors, antioxidants, catalysts, emulsifiers,

and reducing agents; as a starting material in the production of

some insecticides, herbicides, pesticides, dyestuffs, and explosive;

and in the preparation of several pharmaceutical derivatives [1].

Hydrazine is also an ideal fuel for a direct fuel cell system because

its fuel electrooxidation process does not suffer from any poi-

soning effects [2,3]. However, hydrazine is a toxic material that

must be treated with care. Due to the reasons above, it is highly

desirable to fabricate a reliable and sensitive analytical tool for

the effective detection of hydrazine [4]. Previously published work

includes hydrazine detection methods based on flow injection anal-

ysis (FIA) [5,6], ion chromatography [7], chemiluminescence (CL)

and various types of spectroscopy [2,8,9]. However, the processes

involved in many of these methods are extremely complex, and

the linear ranges are relatively narrow and have low precision.

Fortunately, electrochemical techniques offer the opportunity for

portable, cheap and rapid methodologies. However, electrochem-

ical oxidation of hydrazine is kinetically sluggish, and a relatively

high overpotential is required at the carbon electrodes. Therefore,

several approaches have been investigated in an attempt to mini-

mize this high overpotentials problem and to increase the oxidation

current response. One promising approach is the use of chemi-

∗ Corresponding author. Tel.: +86 0553 3869302; fax: +86 0553 3869303.

E-mail address: binfang 47@yahoo.com.cn (B. Fang).

cally modified electrodes (CMEs) containing specifically selected

redox mediators immobilized on conventional electrode materi-

als. As an alternative approach, electrodes such as platinum [10],

rhodium [11] and palladium [12] have been reported as being elec-

trocatalytic for the electrochemical oxidation of hydrazine, but such

metals are too expensive for practical applications.

The II–VI semiconductor ZnO nanostructure presents itself as

one of the most promising materials for the fabrication of efficient

amperometric sensors due to extraordinary properties such as bio-

compatibility, non-toxicity, chemical and photochemical stability,

relatively higher specific-surface area, high electron communica-

tion features and electrochemical activities, and so on [13–17].

Recently, the use of ZnO nanostructures to fabricate an electro-

chemical hydrazine sensor has been reported in the literature

[18,19]. In these works, Nafion was used to form a net-like film,

which is important for tight attachment to the ZnO nanostructures

on the surface of the gold electrode. However, Nafion may actually

result in the formation of a “partially blocked” electrode array sys-

tem; that is, it is likely to coat at least part of the ZnO nanostructured

surface, thereby passivating the modified electrode. Thus, these

immobilization methods can result in a decrease in the electroan-

alytical performance of the electrode. It is well known that carbon

nanotubes (CNTs) are suitable materials for electrode modification

and support in biosensor applications because of the high accessible

surface area, low electrical resistance, extremely high mechanical

strength and stiffness, outstanding charge-transport characteristics

and high chemical stability [20–27]. Therefore, CNTs can be used

to immobilize ZnO nanostructures onto planar electrode surfaces.

This allowed us to take full advantage of the properties of CNTs,

0013-4686/$ – see front matter © 2009 Elsevier Ltd. All rights reserved.

doi:10.1016/j.electacta.2009.08.036

A selective fluorescent sensor for imaging Cu2+ in living cells

Lijuan Jiao,*ab Jilong Li,ab Shengzhou Zhang,c Chao Wei,c Erhong Haoab

and M. Graca H. Vicented

Received (in Montpellier, France) 1st April 2009, Accepted 8th May 2009

First published as an Advance Article on the web 16th June 2009

DOI: 10.1039/b906441a

Copper ion is a biochemically essential yet toxic metal ion, connected to serious

neurodegenerative diseases, and also has been identified as an environmental pollutant. For the

effective detection of Cu2+ in biological and environmental systems, we have developed a new

membrane-permeable Cu2+-selective water-soluble BODIPY 1, which was synthesized by

nucleophilic disubstitution of novel 3,5-diiodo-BODIPY 4 with N,N-bis(2-hydroxyethyl)amines.

BODIPY 1 shows a highly sensitive and selective fluorescence response to Cu2+ in aqueous

solution. Fluorescence image experiments establish that 1 can be used to monitor intracellular

Cu2+ within living cells.

Introduction

Copper ion is a biochemically essential yet toxic metal ion,1

required as a cofactor for many fundamental biological

processes, and catalyzes the production of highly reactive

oxygen species,2 connected to serious neurodegenerative

diseases,3 for example Alzheimer’s disease.3a On the other

hand, it has also been identified as an environmental

pollutant,1b,4 and can affect certain microorganisms at

submicromolar concentrations. Effective detection of Cu2+

can facilitate the study of its physiological role in vivo, and

monitor its presence in metal-contaminated sources, and has

attracted much attention in environmental and biological

analysis areas.1d The design and synthesis of chemosensors

for highly sensitive and selective monitoring of Cu2+ are

highly demanded.

Fluorescent chemosensors have advantages, such as sensitivity,

specificity, simplicity and instantaneous response.5 To be used

for cellular imaging of ions, they also require long-wavelength

excitation and emission, reducing scattering and securing low

background emission. Fluorescent sensors that can permeate

the plasma membrane have proven to be powerful and

non-destructive tools for the study of intracellular metal

ion distributions of calcium(II),6 magnesium(II),7 zinc(II),8

cadmium(II),9 mercury(II),10 or copper(I),11 yet suitable

fluorescent sensors for sensitive in vivo measurements of

intracellular copper(II) levels are lacking. Recently, a large

number of fluorescent probes for Cu2+ has been reported

based on different fluorophores,1b,12 such as anthracene,12a

coumarin,12b,c benzaldehyde hydrazone,12d,e naphthalimide,12f

porphyrin,12g spiropyran,12h rhodamine1b and boron dipyrro-

methene (BODIPY).12i However, most of them have poor

water-solubility and are often characterized in non-aqueous

systems; this together with the requirement for short-

wavelength excitation, and cross-sensitivities toward other

metal cations, hinders their biological applications.

BODIPY dyes, which are widely applied as fluorescent

sensors and labeling reagents,13 have remarkable properties,5c,14

such as high fluorescence quantum yields, high photophysical

stability, and large absorption coefficients. Several positions

are available for the functionalization of BODIPY chromophores.

Most commonly, the derivation is carried out at the pyrrolic

positions,14,15 but functional groups such as ligands or

biomolecules are often introduced via the 8-aryl group.13a

Since the meso-aryl group and the chromophore are almost

perpendicular to each other, electronic conjugation between

the two moieties is weak. On the other hand, derivation at the

pyrrolic position requires the preparation of phenyl or

alkyl-substituted pyrrole building blocks, which is not always

a straightforward synthesis. Moreover, it fails to introduce

electron donating groups without aryl spacers at the

3,5-position due to the difficult synthesis of the corresponding

pyrroles. Alternatively, the direct modification of BODIPY

chromophores via nucleophilic mono- or di-substitution at

3,5-dichloro-BODIPY 2, generated from the NCS chlorination

of dipyrromethane 3 as shown in Scheme 1,16 has been proved

to be efficient. However, NCS chlorination is only suitable for

dipyrromethanes without pyrrolic substituents. Thus only

limited BODIPYs can be generated, and it is necessary to

Scheme 1 Synthetic route for 3,5-dichloro-BODIPY 2.16 Reaction

conditions: (a) NCS; (b) p-chloranil; (c) Et3N, BF3�Et2O.

a Anhui Key Laboratory of Functional Molecular Solids, College ofChemistry and Materials Science, Anhui Normal University, Wuhu,Anhui, 241000, P.R. China. E-mail: jiao421@mail.ahnu.edu.cn;Fax: +86-553-3869303; Tel: +86-553-3869303

bAnhui Key Laboratory of Molecular-Based Materials, Anhui NormalUniversity, Wuhu, Anhui, 241000, P.R. China

c College of Life Science, Anhui Normal University, Wuhu, Anhui,241000, P.R. China

dDepartment of Chemistry, Louisiana State University, Baton Rouge,LA, 70803, USA. E-mail: vicente@lsu.edu; Fax: 225-578-3458;Tel: 225-578-7405

1888 | New J. Chem., 2009, 33, 1888–1893 This journal is �c The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009

PAPER www.rsc.org/njc | New Journal of Chemistry

Modified Kirkendall effect for fabrication of magnetic nanotubesw

Qian Wang, Baoyou Geng,* Shaozhen Wang, Yixing Ye and Bo Tao

Received (in Cambridge, UK) 22nd October 2009, Accepted 14th December 2009

First published as an Advance Article on the web 13th January 2010

DOI: 10.1039/b922134d

In this paper, we successfully synthesize Fe(OH)3 nanotubes

involving the Kirkendall effect. Depending on the calcination

conditions, both haematite and magnetite nanotubes are

produced. This approach also provides a new synthetic alternative

to nanotubes of nonlamellar-structured materials. The

as-synthesized magnetite nanotubes have an application as a

magnetic resonance imaging contrast agent.

Tubular nanostructures exhibit stronger or novel functionalities

due to their higher surface area and their capability of forming

composite structures by embedding specific particles in their

interiors. Iron oxide nanotubes, in particular, have stimulated

extensive research efforts because of their potential application

in diverse areas. Hematite (a-Fe2O3) has been applied to gas

sensors, catalysts and electrode materials.1 Magnetic iron

oxide nanomaterials (Fe3O4 and g-Fe2O3) have been studied

for various biomedical applications including magnetic

resonance imaging (MRI) contrast agents, magnetic-guided

drug-delivery vehicles and the magnetic separation of biological

materials.2 Tubular iron oxide nanostructured materials

have been fabricated using various synthetic routes, such as

template reactions,1a,3 eliminating the core of a core–shell

nanowire,4 rolling up layered materials,5 and hydrothermal

methods.6 However, despite their technological importance,

very limited synthetic efforts have been focused on iron oxide

nanotubes.

The Kirkendall-based fabrication route has recently been

extended to tubular structures.7 In this strategy, solid nano-

wires are transformed into desired materials and morphology

through interface reactions involving the Kirkendall effect.8

Compared with the conventional synthesis techniques, the

merits of the Kirkendall-based method are as follows: (1) It

is template-free and applicable to nonlamellar-structured

materials as well as layered materials; (2) many reactions take

place under mild conditions in solution, so it avoids the

requirement of sophisticated instruments; (3) the size of the

product can be tuned with respect to the original template;

(4) relatively pure products can be obtained and needs no

additional post-processing procedures to remove the templates

and to clean the products; (5) large-scale synthesis can be

achieved in the liquid phase under a mild condition. However,

only a few materials have been found to be suitable for

nanotubes via the Kirkendall-based route in comparison with

their spherical counterparts.9

Here, we demonstrate, as a proof-of-concept, the

Kirkendall-type mass transport, when coupled with interfacial

reactions, can be utilized in synthesizing iron hydroxide and

iron oxide nanotubes. This approach not only enriches iron

oxide chemistry, but also provides a new synthetic alternative

to nanotubes of nonlamellar-structured materials, which could

be applicable to the synthesis of other inorganic tubular

nanostructures. Furthermore, the as-synthesized magnetite

nanotubes are successfully used in contrast enhancement in

magnetic resonance imaging.

Our strategy for the preparation of iron hydroxide and iron

oxide nanotubes followed the process depicted in Fig. 1a.

Single crystalline ZnO nanorods are first fabricated by the

hydrothermal approach (see ESI, Fig. S1w) and then dispersed

in aqueous FeCl3 solution. We anticipate receiving iron

hydroxide nanotubes according to the reaction given by

eqn (1).

3ZnO + 2FeCl3 + 3H2O - 2Fe (OH)3 + 3ZnCl2 (1)

The ZnO and Fe3+ ions can form a diffusion pair. The

coupled reaction/diffusion at the solid–liquid interface could

lead to the quick formation of an interconnected Fe(OH)3shell around the external surface of the ZnO nanorods, as

shown in the ESIw (Fig. S2b). The outer Fe(OH)3 shell

prevents a direct chemical reaction, and further reaction relies

on the diffusion of ZnO and Fe3+ through the shell. Because

O atoms in ZnO diffuse faster than Fe3+ ions, a net outward

flow of O atoms through the Fe(OH)3 shell results in the

opposite transport of lattice vacancies. These vacancies would

condense to form small Kirkendall voids, which are strong

evidence of the Kirkendall effect (see ESI, Fig. S2cw), followedby the voids connected to each other to form the Fe(OH)3nanotubes.

Furthermore, from an experimental point of view, in order

to obtain pure-phase nanotubes, there should be a suitable

amount of shell material relative to the starting crystals.

In light of this, different from the conventional Kirkendall

process, our process is modified with an additional solution-

phase reaction, under which the supply of the shell material is

constant and sufficient. Demonstrated examples include wet

sulfidation of Co nanocrystals.10

Typical SEM and TEM images of the Fe3O4 nanotubes

(Fig. 2a–c) reveal that the products are pure and high-yield

tubular morphology with wall thickness of approximately

10 nm. The morphologies of the obtained Fe(OH)3, a-Fe2O3

and g-Fe2O3 nanotubes are exhibited in Fig. S3 and S4,wrespectively.

College of Chemistry and Materials Science, Anhui Key Laboratoryof Functional Molecular Solids, Anhui Laboratory of Molecular-BasedMaterials, Anhui Normal university, Wuhu, 241000, P. R. China.E-mail: bygeng@mail.ahnu.edu.cn; Fax: (+86)-553-3869303w Electronic supplementary information (ESI) available: ExperimentalSection; Images of the initial ZnO nanorods, a-Fe2O3 and g-Fe2O3

nanotubes; XRD patterns of the products obtained at differentconversion durations. See DOI: 10.1039/b922134d

This journal is �c The Royal Society of Chemistry 2010 Chem. Commun., 2010, 46, 1899–1901 | 1899

COMMUNICATION www.rsc.org/chemcomm | ChemComm

DOI: 10.1002/asia.200900307

Tuned C�H Functionalization to Construct Aza-Podophyllotoxin/Aza-Conidendrin Derivatives by Means of Domino Cyclization

Yimin Hu,*[a] Yuan Qu,[a] Fenghua Wu,[a] Jinghan Gui,[a] Yun Wei,[a] Qiong Hu,[a] andShaowu Wang*[a, b]

Introduction

The synthetic methodology for natural products or their an-alogues has attracted much attention for their medicinal ap-plications. Podophyllotoxin (Scheme 1) is one of the naturalproducts isolated from Podophyllum peltatum and Podo-phyllum emodi,[1] as it has long been known to possess anti-tumor properties in clinical use in the treatment of wartsand small-cell lung carcinoma.[2] Various synthetic strategieshave been developed for the preparation of podophyllotoxinand its analogues.[3] The groups of Linker and Bach devel-

oped the strategies independently by synthesizing (�)-epi-podophyllotoxin[4a] and (�)-podophyllotoxin[4b] throughenantioselective total synthesis. The total synthesis of (�)-epipodophyllotoxin has also been accomplished in 12 stepsstarting from the commercially available piperonal, with thefinal product isolated in 30% overall yield. Sherburn andco-workers constructed the core structure of podophyllotox-in in nine steps with a high regio- and stereoselectivity usinga silicon-tethered radical reaction.[4c] In addition, Davieset al. described an efficient C�H activation of primary ben-zylic positions by means of rhodium carbenoid in the syn-thesis of (�)-a-conidendrin.[5]

As an analogue of podophyllotoxin, aza-epiisopicropodo-phyllin has been synthesized by Poli and Giambastiani by

Abstract: An efficient domino cycliza-tion method for the construction ofaza-podophyllotoxin/aza-conidendrinderivatives has been established. Reac-tions of different dienes with aryl hal-ides in the presence of a palladium cat-alytic system produced different kindsof podophyllotoxin derivatives througha highly regioselective C�H functional-ization. Treatment of dienes with arylhalides that have electron-withdrawingsubstituents on the phenyl ring createdaza-podophyllotoxin derivatives by

means of the functionalization of theC�H bonds ortho to the C�halidebonds of the incoming aryl halides. Thereaction of dienes with 1-iodobenzeneor aryl halides that incorporate elec-tron-donating groups produced aza-conidendrin derivatives by means ofthe functionalization of both sp3 C�H

and sp2 C�H bonds. The regioselectiveC�H functionalization for the forma-tion of different pseudo-podophyllotox-in/-conidendrin derivatives is proven byanalyses of the 1H NMR spectra of theproducts and selective X-ray analysesof the structures of the products. Thus,the palladium-catalyzed domino cycli-zation of 1,6-dienes for the preparationof aza-podophyllotoxin/aza-coniden-drin derivatives can be controlled byselectively controlling the C�H func-tionalization.

Keywords: C-H activation · cycliza-tion · dienes · domino reactions ·palladium

[a] Prof. Dr. Y. Hu, Y. Qu, F. Wu, J. Gui, Y. Wei, Q. Hu,Prof. Dr. S. WangLaboratory of Functional Molecular Solids, Ministry of EducationAnhui Key Laboratory of Molecular-Based MaterialsSchool of Chemistry and Materials ScienceAnhui Normal University, Wuhu, Anhui 241000 (P.R. China)Fax: (+86)553-388-3517E-mail : yiminhu@mail.ahnu.edu.cn

swwang@mail.ahnu.edu.cn

[b] Prof. Dr. S. WangState Key Laboratory of Organometallic Chemistry DepartmentChinese Academy of Sciences, Shanghai 200032 (P.R. China)

Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/asia.200900165.

Scheme 1. Selected natural products containing skeletons of aryl tetrahy-dronaphthalene lactones.

Chem. Asian J. 2010, 5, 309 – 314 � 2010 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim 309

Author's personal copy

Greatly enhanced electrochemiluminescence of CdS nanocrystals upon heating in thepresence of ammonia

Haiyan Wang ⁎, Fuqiang Zhang, Zhian Tan, Qiongfang Chen, Lun Wang ⁎Anhui Key Laboratory of Chemo-biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China

a b s t r a c ta r t i c l e i n f o

Article history:Received 8 February 2010Received in revised form 21 February 2010Accepted 24 February 2010Available online 2 March 2010

Keywords:ElectrochemiluminescenceCdS nanocrystalsAmmoniaHeating

CdS nanocrystals (NCs) usually exhibit very weak electrochemiluminescence (ECL) emission. It is showedthat when CdS NCs were treated by heating in the presence of ammonia (heated-CdS–NH3), greatlyenhanced ECL was observed. The ECL of the heated-CdS–NH3 modified glassy carbon electrode (heated-CdS–NH3/GCE) in phosphate buffer solution (pH 7.0) containing 0.1 M K2S2O8 was ca. 310 times higher than thatof CdS/GCE. The treatment caused the changes in the morphology and surface electronic structure of CdSNCs, which facilitated the reduction process of CdS, consequently improved the quantity of the excited states(CdS*), leading to enormous enhancement in ECL.

© 2010 Elsevier B.V. All rights reserved.

1. Introduction

During the past decades, semiconductor nanomaterials have intriguedgreat interest because of their unique optical and electrical features [1].Since the first report on the electrochemiluminescence (ECL) of Sinanocrystals (NCs) byBard et al. [2–4], growing attentionhas beenpaid tothe ECL studies of semiconductor nanomaterials. Cadmium sulfide (CdS)NCs are one of the most extensively investigated II–VI semiconductornanomaterials in ECL studies due to their intrinsic properties such as theeasy preparation in aqueous solution and potential applications inanalytical fields [5–7].

Zhu et al. [8] have firstly reported the ECL of CdS NCsmodified carbonpaste electrode and they proposed that the morphology of CdS sphericalassembliesplayan important role in generating theECL.However, the lowECL intensity of CdSNCs restricts theirwide analytical applications [9–11].Various approaches have been developed to enhance the ECL of CdSnanostructures. A novel solvothermal route was utilized to prepareflower-like CdS nanostructures and aggregated CdS nanorods whichexhibit strong ECL [9]. Chen et al. [10] reported that the ECL of CdS NCs/carbonnanotubes compositefilms couldbeenhanced ca. 5-fold comparedwith the pure CdS NCs. Wang et al. [11] showed that the CdS–Agnanocomposite arrays exhibited ca. 5-fold enhanced ECL, which isassociated with the surface electronic structure caused by the combina-tion of Ag.

It is well known that surface chemistry plays an important role inachieving high photoluminescence (PL) efficiency and surface modifica-

tion can significantly increases the quantum yield of the PL emissionthrough removing the local trap sites from the surface [12]. Chemicaltreatment is one of the most widely used methods to improve the PLbehavior [13–15]. It is shown that thermal treatment influenced the sizedistribution of CdTeNCs and likely prompted light emission [13]. A drasticincrease in PL efficiency accompanied by a red-shift of the peak positionand a narrowing of the spectral width was observed for the silica-coatedCdTe NCs after heat treatment [14]. Another report shows that incubatingthe thioglycolic acid (TGA) capped CdTe quantum dots (QDs) in analkaline solution containing both ammonia and NaOH not only increasedthe fluorescence quantum yield of the CdTe QDs but also caused highretention of fluorescence throughout the silica coating [15]. Since ECL ismore sensitive to surface state than PL, it is possible that the ECL could beimproved by controlling the surface chemistry through the chemicaltreatment such as heating or incubation with ammonia solution.

In this work, it is found firstly that greatly enhanced ECL could beachieved when the TGA-capped CdS NCs were treated by heating in thepresence of ammonia (heated-CdS–NH3). Compared with the untreatedCdS NCs thin film, ca. 310 times enhanced ECL was obtained for theheated-CdS–NH3 thin filmmodified glassy carbon electrode in phosphatebuffer solution (pH 7.0) containing 0.1 M K2S2O8. The enhancement maybe due to the changes inmorphology and the surface electronic structureof CdS NCs upon heating in the presence of ammonia [11].

2. Experimental

2.1. Chemicals

Sodium hydroxide (NaOH), thioacetamide (CH3CSNH2), andthioglycolic acid (TGA) were purchased from Sinopharm Chemical

Electrochemistry Communications 12 (2010) 650–652

⁎ Corresponding authors. Tel./fax: +86 553 3869303.E-mail addresses: hywang@mail.ahnu.edu.cn (H. Wang),

wanglun@mail.ahnu.edu.cn (L. Wang).

1388-2481/$ – see front matter © 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.elecom.2010.02.022

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DOI: 10.1021/jo101164a Published on Web 08/09/2010 J. Org. Chem. 2010, 75, 6035–6038 6035r 2010 American Chemical Society

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Synthesis and Functionalization of AsymmetricalBenzo-Fused BODIPY Dyes

Lijuan Jiao,* Changjiang Yu, Mingming Liu,Yangchun Wu, Kebing Cong, Ting Meng, Yuqing Wang,

and Erhong Hao

Anhui Key Laboratory of Functional Molecular Solids,College of Chemistry and Material Science, and Anhui KeyLaboratory of Molecular Based Materials, Anhui Normal

University, Wuhu, 241000, China

jiao421@mail.ahnu.edu.cn

Received June 15, 2010

A series of asymmetrical benzo-fused BODIPY dyes weresynthesized from the Sonogashira coupling and nucleophilicsubstitution reactions on the 3-halogenated benzo-fusedBODIPY, generated from readily available 3-halogeno-1-formylisoindoles in a two-step synthetic procedure. Thisnovel BODIPY platform provides an easy path for thelinking of BODIPY fluorophore to various desired function-alities as demonstrated in this work. Most of the resultingBODIPY dyes show long-wavelength absorption and fluor-escence emission,withgood fluorescencequantumyields andlong fluorescence lifetimes.

Boradiazaindacenes, commonlyknownasBODIPYdyes, arestrongly UV-absorbing small molecules with high fluorescencequantum yields, sharp fluorescence emissions, large molarabsorption coefficients, high photochemical stability, and lowsensitivity to the environment,1,2 and they have found wide

applications in highly diverse fields,1 such as labeling rea-gents,3-5 chemosensors,6,7 laser dyes,8 photosensitizers,9 andfluorescence organic devices.10-12 The absorption and emissionwavelengths for classical BODIPY chromophore center at470-530 nm. With regard to their various applications, it isvery necessary to have BODIPYdyes absorbing and emitting atlonger wavelengths. Recently, we and several other groups13-16

have achieved the red-shift of the absorption and fluorescence

(1) (a) Loudet, A.; Burgess, K.Chem. Rev. 2007, 107, 4891. (b)Ulrich, G.;Ziessel, R.; Harriman, A. Angew. Chem., Int. Ed. 2008, 47, 1184. (c) Ziessel,R.; Ulrich, G.; Harriman, A. New J. Chem. 2007, 31, 496.

(2) (a) http://probes.invitrogen.com. In Molecular Probes; InvitrogenCorporation, 2006. (b) Haugland, R. P. The Handbook: A Guide to Fluor-escent Probes and Labeling Technologies, 10th ed.; Molecular Probes, Inc.:Eugene, OR, 2005.

(3) (a) Kabayashi, H.; Ogawa, M.; Alford, R.; Choylle, P. L.; Urano, Y.Chem. Rev. 2010, 110, 2620. (b) Merino, E. J.; Weeks, K. M. J. Am. Chem.Soc. 2005, 127, 12766.

(4) (a) Karolin, J.; Johansson, L. B.-A.; Strandberg, L.; Ny, T. J. Am.Chem. Soc. 1994, 116, 7801. (b) Bergstrom, F.; Hagglof, P.; Karolin, J.; Ny,T.; Johansson, L. B.-A. Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 12477.

(5) (a) Meng, Q.; Kim, D. H.; Bai, X.; Bi, L.; Turro, N. J.; Ju, J. J. Org.Chem. 2006, 71, 3248. (b) Peters, C.; Billich, A.; Ghobrial, M.; Hoegenauer,K.; Ullrich, T.; Nussbaumer, P. J. Org. Chem. 2007, 72, 1842. (c) Li, Z.;Bittman, R. J. Org. Chem. 2007, 72, 8376. (d) Li, Z.;Mintzer, E.; Bittman, R.J. Org. Chem. 2006, 71, 1718.

(6) (a) Coskun, A.; Akkaya, E. U. J. Am. Chem. Soc. 2005, 127, 10464. (b)Yamada, K.; Nomura, Y.; Citterio, D.; Iwasawa, N.; Suzuki, K. J. Am.Chem. Soc. 2005, 127, 6956. (c)Wu,Y.; Peng, X.; Guo, B.; Fan, J.; Zhang, Z.;Wang, J.; Cui, A.; Gao, Y.Org. Biomol. Chem. 2005, 3, 1387. (d) Baruah,M.;Qin, W.; Basari�c, N.; De Borggraeve, W. M.; Boens, N. J. Org. Chem. 2005,70, 4152. (e) Hudnall, T. W.; Gabbai, F. P. Chem. Commun. 2008, 4596. (f)Krumova, K.; Oleynik, P.; Karam, P.; Cosa,G. J. Org. Chem. 2009, 74, 3641.

(7) (a) Zeng, L.; Miller, E. W.; Pralle, A.; Isacoff, E. Y.; Chang, C. J. J.Am. Chem. Soc. 2006, 128, 10. (b)Wang, J.; Qian, X.Org. Lett. 2006, 8, 3721.(c) Yuan,M.; Zhou,W.; Liu, X.; Zhu,M.; Li, J.; Yin, X.; Zheng, H.; Zuo, Z.;Ouyang, C.; Liu, H.; Li, Y.; Zhu., D. J. Org. Chem. 2008, 73, 5008. (d)Coskun, A.; Akkaya, E. U. J. Am. Chem. Soc. 2006, 128, 14474. (e) Hudnall,T.W.;Gabbaı, F. P.Chem. Commun. 2008, 4596. (f) Peng, X.; Du, J.; Fan, J.;Wang, J.;Wu,Y.; Zhao, J.; Sun, S.; Xu, T. J. Am.Chem. Soc. 2007, 129, 1500.

(8) Mula, S.; Ray, A. K.; Banerjee, M.; Chaudhuri, T.; Dasgupta, K.;Chattopadhyay, S. J. Org. Chem. 2008, 73, 2146.

(9) Yogo, T.; Urano, Y.; Ishitsuka, Y.; Maniwa, F.; Nagano, T. J. Am.Chem. Soc. 2005, 127, 12162.

(10) (a) Ulrich, G.; Goeze, C.; Guardigli, M.; Roda, A.; Ziessel, R.Angew. Chem., Int. Ed. 2005, 44, 3694. (b) Loudet, A.; Bandichhor, R.;Wu, L.; Burgess, K. Tetrahedron 2008, 64, 3642. (c) Tan, K.; Jaquinod, L.;Paolesse, R.; Nardis, S.; Natale, C.; Carlo, A.; Prodi, L.; Montalti, M.;Zaccheroni, N.; Smith, K. M. Tetrahdedron 2004, 60, 1099.

(11) (a) Li, F.;Yang, S. I.; Ciringh,Y.Z.; Seth, J.;Martin, C.H.; Singh,D.L.;Kim,D.; Birge,R.R.; Bocian,D.F.;Holten,D.; Lindsey, J. L. J.Am.Chem. Soc.1998, 120, 10001. (b) Yilmaz, M. D.; Bozdemir, O. A.; Akkaya, E. U.Org. Lett.2006, 8, 2871. (c) Erten-Ela, S.; Yilmaz,M.D.; Icli, B.; Dede, Y.; Icli, S.; Akkaya,E.U.Org.Lett.2008,10, 3299. (d)Rousseau,T.;Cravino,A.;Bura,T.;Ulrich,G.;Ziessel, R.; Roncali, J. Chem. Commun. 2009, 1673.

(12) (a) Golovkova, T.A.;Kozlov,D.V.;Neckers,D.C. J.Org. Chem. 2005,70, 5545. (b) Coskun, A.; Deniz, E.; Akkaya, E. U.Org. Lett. 2005, 7, 5187.

(13) Examples for modification of the BODIPY core with aryl, vinyl,styryl, and arylethynyl substituents: (a) Rohand, T.; Baruah, M.; Qin, W.;Boens, N.; Dehaen, W. Chem. Commun. 2006, 266. (b) Rohand, T.; Qin, W.;Boens, N.; Dehaen,W. Eur. J. Org. Chem. 2006, 4658. (c) Li, L.; Nguyen, B.;Burgess, K. Bioorg. Med. Chem. Lett. 2008, 18, 3112. (d) Han, J.; Gonzalez,O.; Aguilar-Aguilar, A.; Pe~na-Cabrera, E.; Burgess, K. Org. Biomol. Chem.2009, 7, 34. (e) Rurack, K.; Kollmannsberger, M.; Daub, J. New J. Chem.2001, 25, 289.

(14) Examples for modification of the BODIPY core with Knoevenagelcondensation reactions: (a) Rurack, K.; Kollmannsberger, M.; Daub, J.Angew. Chem., Int. Ed. 2001, 40, 385. (b) Dost, Z.; Atilgan, S.; Akkaya,E. U. Tetrahedron 2006, 62, 8484. (c) Atilgan, S.; Ekmekci, Z.; Dogan, A. L.;Guc, D.; Akkaya, E. U. Chem. Commun. 2006, 4398. (d) Buyukcakir, O.;Bozdemir, O. A.; Kolemen, S.; Erbas, S.; Akkaya, E. U. Org. Lett. 2009, 11,4644. (e)Baruah,M.;Qin,W.;Flors,C.;Hofkens, J.;Vall�ee,R.A.L.; Beljonne,D.; Van derAuweraer,M.;DeBorggraeve,W.M.; Boens,N. J. Phys. Chem.A2006, 110, 5998. (f) Qin, W.; Baruah, M.; De Borggraeve, W. M.; Boens, N.J. Photochem. Photobiol. A: Chem. 2006, 183, 190.

(15) Examples for modification of the BODIPY core with rigid ringsystem: (a) Wang, Y.-W.; Descalzo, A. B.; Shen, Z.; You, X.-Z.; Rurack,K.Chem.;Eur. J. 2010, 16, 2887. (b) Descalzo, A. B.; Xu, H.-J.; Xue, Z.-L.;Hoffmann, K.; Shen, Z.; Weller, M. G.; You, X.-Z.; Rurack, K. Org. Lett.2008, 10, 1581. (c) Shen, Z.; R€ohr, H.; Rurack, K.; Uno, H.; Spieles, M.;Schulz, B.; Reck, G.; Ono, N. Chem.;Eur. J. 2004, 10, 4853. (d) Wada, M.;Ito, S.; Uno, H.;Murashima, T.; Ono, N.; Urano, T.; Urano, Y.TetrahedronLett. 2001, 42, 6711. (e) Zhao, W.; Carreira, E. M. Angew. Chem., Int. Ed.2005, 44, 1677. (f) Zhao, W.; Carreira, E. M. Chem.;Eur. J. 2006, 12, 7254.(g) Umezawa, K.; Nakamura, Y.; Makino, H.; Citterio, D.; Suzuki, K. J.Am. Chem. Soc. 2008, 130, 1550. (h) Mei, Y.; Bentley, P. A.; Wang, W.Tetrahedron Lett. 2006, 47, 2447. (i) Chen, J.; Burghart, A.; Derecskei-Kovacs, A.; Burgess, K. J. Org. Chem. 2000, 65, 2900.

(16) (a) Jiao, L.; Yu, C.; Li, J.; Wang, Z.; Wu, M.; Hao, E. J. Org. Chem.2009, 74, 7525. (b) Jiao, L.; Li, J.; Zhang, S.; Wei, C.; Hao, E.; Vicente,M. G. H. New J. Chem. 2009, 33, 1888. (c) Jiao, L.; Yu, C.; Uppal, T.; Liu,M.; Li, Y.; Zhou, Y.; Hao, E.; Hu, X.; Vicente, M. G. H. Org. Biol. Chem.2010, 8, 2517.

DOI: 10.1021/la104022g 18723Langmuir 2010, 26(24), 18723–18727 Published on Web 11/29/2010

pubs.acs.org/Langmuir

© 2010 American Chemical Society

Facile Subsequently Light-Induced Route to Highly Efficient and StableSunlight-Driven Ag-AgBr Plasmonic Photocatalyst

Long Kuai, Baoyou Geng,* Xiaoting Chen, Yanyan Zhao, and Yinchan Luo

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids,Anhui Laboratory of Molecular-Based Materials, Anhui Normal University, Wuhu, 241000, P. R. China

Received October 6, 2010. Revised Manuscript Received November 15, 2010

In this paper, we successfully fabricate a stable and highly efficient direct sunlight plasmonic photocatalyst Ag-AgBrthrough a facile hydrothermal and subsequently sunlight-induced route. The diffuse reflectance spectra of Ag-AgBrindicate strong absorption in both UV and visible light region. The obtained photocatalyst shows excellent sunlight-driven photocatalytic performance. It can decompose organic dyewithin severalminutes under direct sunlight irradiation andmaintain a high level even though used five times. In addition, both the scanning electron microscopy images and X-rayphotoelectron spectroscopy dates reveal the as-prepared photocatalyst to be very stable. Moreover, the mechanismsuggests that the high photocatalytic activity and excellent stability result from the super sensitivity of AgBr to light, thesurface plasmon resonance of Ag nanoparticles in the region of visible light, and the complexation between Agþ andnitrogen atom. Thus, the facile preparation and super performance of Ag-AgBrwill make it available to utilize sunlightefficiently to remove organic pollutants, destroy bacteria, and so forth.

1. Introduction

Currently, the “Green-Life” concept is inspiring enthusiasmto exploit efficient and stable photocatalysts in the visible lightregion. Compared with other physical, chemical, and biologicalmethods, the photodecomposition approach is more acceptablein decomposing organic pollutants.1-4 TiO2 seems to be the mostpromising photocatalyst due to its stability, nontoxicity, and low-cost. However, its practical application is limited by its low utili-zation efficiency of solar because of the restricted absorption inultraviolet (UV) region, which only account for 4% of the wholesolar spectrum. Moreover, although many methods, includingnoblemetal deposition, complex semiconductors, ion doping, anddye sensitization methods, have been explored to improve theproperties of TiO2, there are still some other shortcomings.5

Therefore, it is necessary to develop some novel photocatalyststo remove the pollutants.

Silver halide has been supposed to be a new visible light photo-catalytie material for its good sensitivity to light. During its

application, silver halide is usually loadedon someothermaterialsto perform its catalytic properties.6-12 However, this property ofsilver halide rarely plays a main role in these catalysts, resulting innot perfect efficiency. Considering the surface plasmon resonance(SPR) of noble metal nanoparticles, some highly efficient visible-light plasmonic photocatalysts appear. For example, Farnood etal. prepared photocatalyst AgBr/Y-zeolite,13 which is highlyefficient under sunlight irradiation, but it is so unstable that itspractical application will be also limited. Some other visible-lightphotocatalysts, such as Ag@AgCl and Ag@AgBr have beendeveloped recently.14-18 These catalysts display high photocata-lytic activity and stability under visible-light due to the SPR ofsilver nanoparticles produced at the surface of silver halide. How-ever, the fabrication method is multistep or time-consuming, andthe produced silver nanoparticles are large and polydisperse,resulting in seriously weakening of the SPRof silver nanoparticles

Scheme 1. The Production of Silver Nanoparticles on AgBrand the Proposed Photocatalytic Mechanism of Ag-AgBr

Plasmonic Photocatalyst

*Corresponding author. E-mail: bygeng@mail.ahnu.edu.cn. Fax: (þ86)-553-3869303.(1) Arai, T.; Yanagida, M.; Konishi, Y.; Iwasaki, Y.; Sugihara, H.; Sayama, K.

J. Phys. Chem. C 2007, 111, 7574.(2) Huang, J. H.; Cui, Y. J.; Wang, X. C. Environ. Sci. Technol. 2010, 44, 3500.(3) Zeng, H. B.; Cai, W. P.; Li, Y.; Hu, J. L.; Liu, P. S. J. Phys. Chem. B 2005,

109, 18260.(4) Zeng, H. B.; Cai, W. P.; Liu, P. S.; Xu, X. X.; Zhou, H. J.; Klingshirn, C.;

Kalt, H. ACS Nano 2008, 2, 1661.(5) Han, H.; Bai, R. B. Ind. Eng. Chem. Res. 2009, 48, 2891.(6) Hu, C.; Peng, T. W.; Hu, X. X.; Nie, Y. L.; Zhou, X. F.; Qu, J. H.; He, H.

J. Am. Chem. Soc. 2010, 132, 857.(7) Huo, P.W.; Yan, Y. S.; Li, S. T.; Li, H.M.; Huang,W.H.Desalination 2010,

256, 196.(8) Elahifard, M. R.; Rahimnejad, S.; Haghighi, S.; Gholami, M. R. J. Am.

Chem. Soc. 2007, 129, 9552.(9) Hu, C.; Lan, Y. Q.; Qu, J. H.; Hu, X. X.;Wang, A.M. J. Phys. Chem. B 2006,

110, 4066.(10) Zang, Y. J.; Farnood, R. Appl. Catal. B: Environ 2008, 79, 334.(11) Wang, P.; Huang, B. B.; Qin, X. Y.; Zhang, X. Y.; Dai, Y.; Whangbo,

M. H. Inorg. Chem. 2009, 48, 10697.(12) Li, G. T.; Wong, K. H.; Zhang, X. W.; Hu, C.; Yu, J. C.; Chan, R. C. Y.;

Wong, P. K. Chemosphere 2009, 76, 1185.

(13) Zang, Y. J.; Farnood, R.; Currie, J. Chem. Eng. Sci. 2009, 64, 2881.(14) Wang, P.; Huang, B. B.; Qin, X. Y.; Zhang, X. Y.; Dai, Y.; Wei, J. Y.;

Whangbo, M. H. Angew. Chem., Int. Ed. 2008, 47, 7931.(15) Wang, P.; Huang, B. B.; Zhang, X. Y.; Qin, X. Y.; Jin, H.; Dai, Y.; Wang,

Z. Y.;Wei, J. Y.; Zhan, J.;Wang, S.Y.;Wang, J. P.;Whangbo,M.H.Chem.;Eur.J. 2009, 15, 1821.

(16) An, C. H.; Peng, S.; Sun, Y. G. Adv. Mater. 2010, 22, 2570.(17) Wang, P.; Huang, B. B.; Lou, Z. Z.; Zhang, X. Y.; Qin, X. Y.; Dai, Y.;

Zheng, Z. K.; Wang, X. N. Chem.;Eur. J. 2010, 16, 538.(18) Bi, Y. P.; Ye, J. H. Chem.;Eur. J. 2010, 16, 10327.

COMMUNICATION www.rsc.org/obc | Organic & Biomolecular Chemistry

Long wavelength red fluorescent dyes from 3,5-diiodo-BODIPYs†

Lijuan Jiao,*a Changjiang Yu,a Timsy Uppal,b Mingming Liu,a Yan Li,a Yunyou Zhou,a Erhong Hao,a

Xiaoke Hub and M. Graca H. Vicente*b

Received 19th January 2010, Accepted 6th April 2010First published as an Advance Article on the web 14th April 2010DOI: 10.1039/c001068e

Amphiphilic and long wavelength red fluorescent dyes (4 and7) were prepared from the Sonogashira coupling reactionsof 3,5-diiodo-BODIPYs (1 and 6). One of these compounds,BODIPY 7, readily accumulated within human carcinomaHEp2 cells and was found to localize mainly within theendoplasmic reticulum (ER).

BODIPYs have recently attracted much research interest in diversefields,1,2 for example as labeling reagents,1–5 fluorescent switches,6

chemosensors,7,8 laser dyes,9 photosensitizers,10 energy transfercassettes,11 and harvesting arrays,12 due to their remarkableproperties,2 including large absorption extinction coefficients,sharp fluorescence emissions, high fluorescence quantum yields,high photophysical stability, and low sensitivity to the polarity andpH of their environment. BODIPYs possessing long wavelengthabsorption and emission profiles in the red and near infraredregion (650–900 nm) of the spectrum are particularly promisingfor biological applications since the background absorption, lightscattering and the autofluorescence of cell components are largelyreduced.3a

Long wavelength absorbing and emitting BODIPYs are of-ten obtained by extending the conjugation of the BODIPYchromophore via functionalization of the pyrrolic positions.13

Usually, this is achieved via de novo syntheses from appropri-ately substituted pyrroles14 (if readily accessible), for examplebenzo-/naphtho-fused BODIPYs.15 On another hand, significantbreakthroughs in this area were achieved with the developmentof three ready-made BODIPY platforms as shown in Fig. 1: the3,5-dimethyl-BODIPYs (A),16 the 3,5-dichloro-BODIPYs (B),17

and the 3,5-dithioalkyl-BODIPYs (C).18 These platforms providea convenient way for the functionalization of the 3,5-pyrrolic posi-tions of the chromophore, and have been used to introduce variousfunctionalities, in particular aryl, alkenyl or alkynyl groups,therefore conferring desired long wavelength absorption/emissionproperties on the BODIPY core. However, BODIPY A canonly react with specific types of aryl adehydes under harshconditions, and BODIPYs B and C generally lack b-pyrrolicsubstituents. Herein we report an alternative BODIPY platformcomplementary to A–C, bearing 3,5-diiodo substituents, and theuse of this platform in Sonogashira coupling reactions leadingto the efficient generation of several long wavelength emitting

aLaboratory of Functional Molecular Solids, Ministry of Education; AnhuiLaboratory of Molecule-Based Materials; School of Chemistry and Ma-terials Science, Anhui Normal University, Wuhu, Anhui, China, 241000.E-mail: jiao421@mail.ahnu.edu.cn; Fax: (+86) 553-388-3517bDepartment of Chemistry, Louisiana State University, Baton Rouge, LA,70803. E-mail: vicente@lsu.edu; Fax: (+) 225-578-7405† Electronic supplementary information (ESI) available: The synthesis andcharacterization data of all products. See DOI: 10.1039/c001068e

Fig. 1 Common routes for the functionalizations of the BODIPYchromophore at the 3,5-positions.

fluorescent BODIPYs. Preliminary in vitro studies on one of thesedyes indicate that this type of compound is highly membranepermeable and it can selectively localize within specific subcellularorganelles, suggesting promising biological applications for thesemolecules, namely in bioimaging.

The 3,5-diiodo-BODIPY 1 was obtained in 90% yield uponBF3·Et2O complexation of 1,9-diiodo-dipyrromethene 2, asshown in Scheme 1. Dipyrromethene 2 was synthesized fromdipyrromethane 3 using the literature procedure.19 This synthesiscan be scaled up to a multigram scale with minimal chromatogra-phy isolation. In addition to compound 2, a variety of 1,9-diiodo-dipyrromethenes are readily available, since dipyrromethanes Dwith various pyrrolic functionalities have been widely used innumerous [2+2] syntheses of porphyrins E.20

Scheme 1 Synthesis of 3,5-diiodoBODIPY 1 from readily available3. Reaction conditions: (i) Pd/C, H2, THF, 96%; (ii) I2, NaHCO3,MeOH–H2O, r.t. 80%; (iii) DDQ, 60%; (iv) Et3N, BF3·Et2O, 90%.

The Sonogashira coupling reactions of arylethynes and BOD-IPY B at 80 ◦C have been reported.17 Consequently, we anticipatedhigher reactivity of the 3,5-diiodo-BODIPY platform in thisreaction. BODIPY 1 did show superior reactivity in the Pd(0)-catalyzed Sonogashira coupling reactions, smoothly generatingthe desired long wavelength fluorescent dyes 4a–c as dark bluesolids in 66–67% yields within 2 h at 60 ◦C, as shown in Scheme 2.

Fig. 2 shows normalized absorbance (a) and fluorescence (b)spectra for compounds 1 and 4a–c. The newly added arylethynyl

This journal is © The Royal Society of Chemistry 2010 Org. Biomol. Chem., 2010, 8, 2517–2519 | 2517

Electrochimica Acta 55 (2010) 2835–2840

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A hydroxylamine electrochemical sensor based on electrodeposition of porous

ZnO nanofilms onto carbon nanotubes films modified electrode

Cuihong Zhang, Guangfeng Wang, Min Liu, Yuehua Feng, Zhidan Zhang, Bin Fang ∗

College of Chemistry and Materials Science, Anhui Key Laboratory of Chem-Biosensing, Beijing East Road No. 1, Anhui Normal University, Anhui, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 29 October 2009

Received in revised form

20 December 2009

Accepted 22 December 2009

Available online 11 January 2010

Keywords:MWCNTs

ZnO

Modified electrode

Electrocatalysis

Hydroxylamine

a b s t r a c t

A novel route (electrodeposition) for the fabrication of porous ZnO nanofilms attached multi-walled car-

bon nanotubes (MWCNTs) modified glassy carbon electrodes (GCEs) was proposed. The morphological

characterization of ZnO/MWCNT films was examined by scanning electron microscopy (SEM) and X-ray

powder diffraction (XRD). The performances of the ZnO/MWCNTs/GCE were characterized with cyclic

voltammetry (CV), Nyquist plot (EIS) and typical amperometric response (i–t). The potential utility of

electrodes constructed was demonstrated by applying them to the analytical determination of hydroxy-

lamine concentration. An optimized limit of detection of 0.12 �M was obtained at a signal-to-noise ratio

of 3 and with a fast response time (within 3 s). Additionally, the ZnO/MWCNTs/GCE exhibited a wide

linear range from 0.4 to 1.9 × 104 �M and higher sensitivity. The ease of fabrication, high stability, and

low cost of the modified electrode are the promising features of the proposed sensor.

© 2010 Elsevier Ltd. All rights reserved.

1. Introduction

Hydroxylamine, NH2OH (abbreviated as HA), a derivative of

ammonium, is an intermediate in two important microbial pro-

cesses of the nitrogen cycle: it is formed during nitrification as

well as during anaerobic ammonium oxidation [1,2]. Although it is

a well-known mutagen, moderately toxic and harmful to human,

animals, and even plants [3], which has been known to cause both

reversible and irreversible physiological changes [4], it is available

commercially and frequently used industrially widely in pharma-

ceutical intermediates and final drug substances synthesis, nuclear

fuel reprocessing and the manufacturing of semiconductors [5]. In

recent years, chemists became aware of the potentials of hydroxy-

lamine as a result of two major accidents, one occurred in the USA in

February 1999, which killed five people, and the other occurred in

Japan in June 2000, which killed four people [6,7]. Therefore, from

the industrial, environmental and health viewpoints, development

of a sensitive analytical method for the determination of low levels

of hydroxylamine is of significant importance.

The reported methods of the hydroxylamine determination

include spectrophotometry [8], high performance liquid chro-

matography [9], gas chromatography [10], potentiometry [11],

polarography [12] and biamperometry [13]. However, the pro-

∗ Corresponding author. Tel.: +86 553 3869302; fax: +86 553 3869303.

E-mail address: binfang 47@yahoo.com.cn (B. Fang).

cesses involved in many of these methods are extremely complex,

and the linear ranges are relatively narrow and have low precision.

Fortunately, electrochemical techniques offer the opportunity for

portable, cheap and rapid methodologies. However, hydroxylamine

cannot be electrooxidized at bare carbon electrodes. One promis-

ing approach is the use of chemically modified electrodes (CMEs)

containing specifically selected redox mediators immobilized on

conventional electrode materials. Recently, various chemically

modified electrodes (CMEs) have been prepared and applied in

the determination of hydroxylamine [14–18], which can signifi-

cantly lower the overpotentials and increase the oxidation current

response.

In recent years, the II–VI semiconductor zinc oxide (ZnO)

nanostructures have drawn many attentions in the application of

efficient amperometric sensors with many extraordinary proper-

ties, including nontoxicity, biological compatibility, chemical and

photochemical stability, high electrochemical activities and easy

preparation, and so on [19–24]. For example, the use of ZnO nanos-

tructures to fabricate electrochemical sensor have been reported in

the literature [25,26,46–48]. Among various fabrication strategies

of nano- or microscaled ZnO, such as precipitation [27], thermal

decomposition [28] and electrodeposition [29], the one-step elec-

trochemical deposition method by treatment of the reactant in

different solvents seems to be the simplest and most effective

way to prepare nicely crystallized ZnO at relatively low temper-

atures, exempted from further calcination. However, as for the

electrodeposition, the template strategy (anodic alumina mem-

brane or porous polycarbonate membrane) was often used and

0013-4686/$ – see front matter © 2010 Elsevier Ltd. All rights reserved.

doi:10.1016/j.electacta.2009.12.068

Electrochimica Acta 55 (2010) 7204–7210

Contents lists available at ScienceDirect

Electrochimica Acta

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Detection of hydrazine based on Nano-Au deposited on Porous-TiO2 film

Guangfeng Wanga,b, Cuihong Zhanga,b, Xiuping Hea,b, Zejun Lia,b, Xiaojun Zhanga,b,Lun Wanga,b,∗, Bin Fanga,b

a College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Key Laboratory of Chem-Biosensing,Anhui Normal University, Wuhu 241000, PR Chinab Anhui Key Laboratory of Controllable Chemistry Reaction & Material Chemical Engineering, HeFei University of Technology, Hefei 230009, PR China

a r t i c l e i n f o

Article history:Received 6 May 2010

Received in revised form 10 July 2010

Accepted 17 July 2010

Available online 23 July 2010

Keywords:Porous-TiO2

Nano-Au

Hydrazine

a b s t r a c t

The fabrication of Nano-Au/Porous-TiO2 composite modified glassy carbon electrode (GCE) and its

application in the determination of hydrazine were proposed. The morphological characterization was

examined by transmission electron microscope and scanning electron microscopy. The Nano-Au/Porous-

TiO2/GCE exhibited a wide linear range of hydrazine from 2.5 to 500 �M, with a detection limit of 0.5 �M

at a signal-to-noise ratio of 3 and with a fast response time (within 3 s). Furthermore, the reaction mech-

anism of the hydrazine on the Nano-Au/Porous-TiO2/GCE was explored. The ease of fabrication, high

stability, and low cost of the modified electrode are the promising features of the proposed sensor.

© 2010 Elsevier Ltd. All rights reserved.

1. Introduction

Hydrazine is widely used as a fuel in rocket propulsion systems,

also pesticides, blowing agents, pharmaceutical intermediates,

photographic chemicals, and so on [1]. Symptoms of acute expo-

sure to high levels of hydrazine include irritation of eyes, nose,

and throat, temporary blindness, dizziness, nausea, pulmonary

edema and coma in humans. Acute exposure can also damage the

liver, kidneys, and central nervous system in humans [2]. All the

above make their detection and quantitation problems of consider-

able analytical interest. Among several techniques, electrochemical

techniques offer the opportunity for portable, economical, sensi-

tive and rapid methodologies for the determination of hydrazine

[3]. The anodic oxidation of hydrazine happens on noble metals or

carbon electrodes, but they are all accompanied with large over-

potentials. Therefore various materials have been applied to solve

the problem, such as metal complexes of phthalocyanine [4,5], por-

phyrins [6,7], hexacyanoferrates [8], overoxidized polypyrrole [9]

and some organic substances with an o-hydroquinone or hydro-

quinone structure [10,11]. Recently, the nanoparticles have been

used to enhance the electron-transfer rate and to reduce the over-

potential for the oxidation of hydrazine, due to the exotic properties

∗ Corresponding author at: College of Chemistry and Materials Science, Anhui

Key Laboratory of Functional Molecular Solids, Anhui Key Laboratory of Chem-

Biosensing, Anhui Normal University, Wuhu 241000, PR China. Fax: +86 0553

3869303.

E-mail address: wangyusandra@yahoo.com.cn (L. Wang).

of nanostructures [12,13]. However, developing fast method and

easy nanocomposites for the determination of hydrazine is still very

necessary.

Titanium dioxide (TiO2) is an n-type semiconductor material.

Because of its good biocompatibility, stability and environmental

safety, it has been used in lots of areas such as paint indus-

try, biomedicine and environmental engineering [14]. Mesoporous

materials with tunable pore structure and tailored framework com-

position have found broad applications ranging from catalysis,

energy storage and conversion, adsorption, separation and sens-

ing technology to electronics, batteries and biological uses [15–18].

Among this material family, mesoporous titania is of particular

interest since the semiconductive framework is photoactive while

mesoporous channels offer larger surface area and enhanced acces-

sibility [19]. So recently, much more attention has been paid to

the research and application of mesoPorous-TiO2 film for biosensor

design. MesoPorous-TiO2 film displays many novel characteristics,

such as high ratio of surface area to volume, good stability and bio-

compatibility. So it can be used as various immobilization matrix

[20–23].

Noble metal nanoparticles have been extensively utilized in

recent years, owing to their extraordinarily catalytic activities for

both oxidation and reduction reactions [23]. Due to the unique

properties of gold nanomaterials (Nano-Au), such as good con-

ductivity, useful electrocatalytic capability and biocompatibility,

many researchers have been devoted to fabricate Nano-Au elec-

trochemical sensors and biosensors [24–28]. Taking account of the

advantages of Nano-Au and Porous-TiO2, depositing Nano-Au on

matrix of Porous-TiO2 will be a promising composite.

0013-4686/$ – see front matter © 2010 Elsevier Ltd. All rights reserved.

doi:10.1016/j.electacta.2010.07.053

Electrochimica Acta 55 (2010) 7182–7187

Contents lists available at ScienceDirect

Electrochimica Acta

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An unusual H2O2 electrochemical sensor based on Ni(OH)2 nanoplates

grown on Cu substrate

Aixia Gua,c, Guangfeng Wanga,c, Jing Gua, Xiaojun Zhanga,b,∗, Bin Fanga,c,∗

a College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR Chinab Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, PR Chinac Anhui Key Laboratory of Chem-Biosensing, Anhui Normal University, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 22 May 2010

Received in revised form 7 July 2010

Accepted 7 July 2010

Available online 15 July 2010

Keywords:Cu–Ni(OH)2

Nanocomposites

Electocatalysis

Amperometric sensor

H2O2

a b s t r a c t

In this work, Ni(OH)2 nanoplates grown on the Cu substrate were synthesized and characterized by scan-

ning electron microscopy (SEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy

(XPS). Then a novel Cu–Ni(OH)2 modified glass carbon electrode (Cu–Ni(OH)2/GCE) was fabricated and

evaluated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and typical amper-

ometric response (i–t) method. Exhilaratingly, the Cu–Ni(OH)2/GCE shows significant electrocatalytic

activity toward the reduction of H2O2. At an applied potential of −0.1 V, the sensor produces an ultrahigh

sensitivity of 408.1 �A mM−1 with a low detection limit of 1.5 �M (S/N = 3). The response time of the

proposed electrode was less than 5 s. What’s more, the proposed sensor displays excellent selectivity,

good stability, and satisfying repeatability.

© 2010 Elsevier Ltd. All rights reserved.

1. Introduction

At present, nanomaterial-modified glass carbon electrodes can

significantly improve their analytical performance [1,2]. Numerous

excellent materials have been applied to many analytical appli-

cations, such as carbon nanotubes [3], transition metal oxides

[4], prussian blue [5], conducting polymers [6], and carbon nan-

otubes/prussian blue nanocomposites [7].

Nickel hydroxide (Ni(OH)2), as one of the most important tran-

sition metal hydroxides, has been widely used as positive electrode

active materials in alkaline rechargeable Ni-based batteries [8]. It

is well known that layered double hydroxide (LDH) is well-defined

layered structure, which is widely applied as electrochemical

sensor materials [9,10]. Hexagonal �-Ni(OH)2 possesses similar

layered structure to LDH. Unfortunately, synthesizing LDH is quite

difficult and the fabrication of some LDH modified electrodes is very

complicated and time-consuming [11]. Hence, we consider that �-

Ni(OH)2 may be a substitute for LDH as electrochemical sensor

materials. However, there are few reports about electrochemical

sensors based on Ni(OH)2 [12].

∗ Corresponding authors at: College of Chemistry and Materials Science, Anhui

Normal University, Wuhu 241000, PR China. Tel.: +86 0553 3869302;

fax: +86 0553 3869303.

E-mail addresses: zhangxiaojun173@yahoo.com.cn (X. Zhang),

binfang 47@yahoo.com.cn (B. Fang).

Recently, some multidimensional nanomaterials have been pre-

pared by material scientists. Attaching these nanostructures onto

certain support makes the resultant products be feasibility in some

special applications, thus more and more attention has been paid to

the research field [13]. Our group has successfully constructed elec-

trochemical sensors based on Cu–CuO and Cu–Ag2O nanomaterials.

The satisfying properties of these sensors have been acquired. It is

estimated that the improved electrochemical performance might

be due to the electric Cu substrate [14,15]. Considering the poten-

tial of Ni(OH)2 as electrochemical sensor materials, inspired by our

previous work, we prepared Ni(OH)2 nanoplates grown on Cu sub-

strate to fabricate a new electrochemical sensor.

It is no doubt that hydrogen peroxide (H2O2) is a useful com-

pound widely used in modern medicine, environmental control,

and various branches of industry. Up to now, there have been

considerable interests in the accurate determination of H2O2. Elec-

trochemical sensing of H2O2 has been a vigorous alternative to

spectrophotometric [16,17] and chemiluminescence techniques

[18,19] for H2O2 detection, owing to its low cost, high sensitiv-

ity, ease of operation, and high efficiency [9,20,21]. In the past

few decades, a number of excellent reports have focused on the

electrochemical determination of H2O2 utilizing metal [22], carbon

nanotubes [3], layered double hydroxide [11], prussian blue [5], and

conducting polymers [6] modified electrodes. However, to the best

of our knowledge, there are no reports about the detection of H2O2

using the Cu–Ni(OH)2 nanocomposites modified electrodes.

In this paper, we present the fabrication of a H2O2 amperomet-

ric sensor based on Cu–Ni(OH)2 nanocomposites. The proposed

0013-4686/$ – see front matter © 2010 Elsevier Ltd. All rights reserved.

doi:10.1016/j.electacta.2010.07.023

Author's personal copy

DMAP-catalyzed cascade reaction: one-pot synthesis of benzofurans in water

Yongjia Shang *, Cuie Wang, Xinwei He, Kai Ju, Min Zhang, Shuyan Yu, Jiaping WuKey Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science,Anhui Normal University, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 16 June 2010Received in revised form 3 August 2010Accepted 29 September 2010Available online 4 November 2010

Keywords:BenzofuranCascade reactionDimethylaminopyridineHalogenated ketonesSalicylaldehydes

a b s t r a c t

A series of benzofurans were efficiently synthesized in good to excellent yields using 4-dimethylami-nopyridine (DMAP) catalyzed cascade reaction between salicylaldehydes and halogenated ketones inwater at 80 �C opened atmosphere.

Crown Copyright � 2010 Published by Elsevier Ltd. All rights reserved.

1. Introduction

Benzofuran derivatives are important components of those clin-ically used plant extracts due to their excellent properties, such asantibacterial,1 antimicrobial,2 antitumor,3 and the ability to controlcalcium level.4 Many research efforts have been focused on the ef-ficient synthesis of these molecules.5 Typical approaches including:(1) intramolecular enolated O-arylation6 and thio-enolated S-aryla-tion,7 (2) annulation of a furan ring onto a preexisting benzene ring,8

and (3) catalyzed cyclization-coupling.9,10 However, the first twoapproaches generally require multi-step synthesis, while the thirdone often requires the usage of transition-metals,11,12 and only lim-ited types of benzofuran derivatives are accessible using these syn-thetic approaches. The RapeStoermer reaction provides opportunityfor the direct preparation of benzofurans via base-mediated reactionof salicylaldehydes with haloketones. Recently reported solid statestudies on the RapeStoermer reaction provided valuable insightsinto the mechanistic details of this reaction.13

DMAP and its analogs have been widely used in many organicsynthesis as catalyst, used, for example, in the acylation reactions,14

aldol reactions,15 and BayliseHillman reactions.16 Recently, thesecatalysts have also been used in the Michael-addition17 and ester-ification18 reactions in water. Attracted to the efficiency of theseorgano-catalysts and the advantages of using water as solvent.19e22

In the context of our studies aimed for the development of efficientcatalytic organic synthsis,23 we have focused on the utility of DMAP.Herein we report a facile synthesis of a series of benzofurans usingDMAP-catalyzed cascade reaction between readily available sali-cylaldehydes 1 and halogenated ketones 2 in water (Scheme 1).

2. Results and discussion

Initially, DABCO (1, 4-diazabibicyclo [2.2.2] octane) was used ascatalyst in the cascade reaction between salicylaldehyde 1 anda-bromoacetophenone 2 in the presence of Na2CO3 in water asshown in Table 1 (entry 1). To our delight, the desired benzofuran3a24,25 was obtained in 80% yield after reacting at 80 �C for 5 h. Itwas characterized by 1H, 13C NMR and X-ray (Fig. 1). For the opti-mization of the reaction condition, various catalysts, different sol-vents, varying temperature, and reaction time were investigatedand the results are summarized in Tables 1 and 2.

Among the various catalysts studied (Table 1), 3-HQD(3-hydroxyquinuclidine) (entry 2) and DMAP (4-dimethylamino-pyridine) (entry 7) showed higher catalytic activities, and gave

O

R3

O

+

1 2 3

iR3

X

O

R1

R2

R2

OH

O

R1

Scheme 1. Synthesis of benzofuran derivatives conditions: (1) DMAP (0.1 equiv), (2)Na2CO3 (1.5 equiv), (3) H2O (solvent), 80 �C, 5 h.

* Corresponding author. Fax: þ86 553 3869303; e-mail address: shyj@mail.ahnu.edu.cn (Y. Shang).

Contents lists available at ScienceDirect

Tetrahedron

journal homepage: www.elsevier .com/locate/ tet

0040-4020/$ e see front matter Crown Copyright � 2010 Published by Elsevier Ltd. All rights reserved.doi:10.1016/j.tet.2010.09.095

Tetrahedron 66 (2010) 9629e9633

Journal of Membrane Science 364 (2010) 203–210

Contents lists available at ScienceDirect

Journal of Membrane Science

journa l homepage: www.e lsev ier .com/ locate /memsci

Manipulating membrane permeability and protein rejection of UV-modified

polypropylene macroporous membrane

Hai-Yin Yu ∗, Jin Zhou, Jia-Shan Gu ∗, Song Yang

Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science,Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000, China

a r t i c l e i n f o

Article history:Received 22 May 2010

Received in revised form 6 August 2010

Accepted 8 August 2010

Available online 14 August 2010

Keywords:Chain transfer agent

Membrane surface modification

Photo-induced graft polymerization

Polypropylene macroporous membrane

Protein fouling

a b s t r a c t

A three-step photo-induced graft polymerization of 2-hydroxylethyl acrylate (HEA) on the polypropylene

macroporous membrane was carried out by using the chain transfer agent (CTA) benzyl dithiobenzoate

(BDTB). Firstly, benzophenone was immobilized on the membrane surface; secondly, polyHEA (PHEA)

was grafted on the membrane surface under UV irradiation in the presence of HEA and BDTB; thirdly, the

PHEA grafted membranes with and without CTA moieties were respectively immersed in a thermostated

water bath at 55 ◦C for the further grafting polymerization of HEA; in this step, PHEA was also grafted

on the second-step modified membrane, with the grafted membrane containing CTA moieties served as

macro-CTA and azodiisobutyronitrile (AIBN) as initiator.

The degree of grafting (DG) of PHEA increased with UV irradiation time in the first step. In the sec-

ond step, DG increased with UV irradiation time and monomer concentration, and with the decrease of

CTA concentration. In the third step, DG continuously increased with reaction time under thermostated

conditions without adding the free radical initiator; for the PHEA grafted membranes with CTA moieties

on the grafting chain, DG was relatively higher than that for the PHEA grafted membranes without CTA

moieties; also PHEA was grafted on the membrane surface by using the second-step modified membrane

as the macro-CTA and AIBN as initiator, DG continued to increase with the reaction time.

The pure water flux increased with the rise of DG up to 4.48 wt.%, then it decreased gradually, which

shared the same trend with the water flux during the filtration of protein dispersion. The flux recovery

ratio after water cleaning also increased with the rise of DG. But the rejection of protein dispersion

followed the reversed trend of the pure water flux: it decreased down to 4.48 wt.% then increased with

the rise of DG.

© 2010 Elsevier B.V. All rights reserved.

1. Introduction

Membranes, especially polypropylene porous membranes, were

widely used in many fields such as ultrafiltration and microfil-

tration because of the low cost and easy processing. However,

some disadvantages (hydrophobicity, poor antifouling character-

istics and so on) limit its wider application. Surface modification of

membranes becomes more and more important in the membrane

science to endow membranes with desired properties.

There are many methods to modify the membrane surface, such

as UV irradiation [1,2], plasma treatment, grafting polymerization

and physical adsorption [3]. The surface grafting polymerization

is a very effective approach to permanent surface hydrophiliza-

∗ Corresponding authors. Tel.: +86 553 3869303; fax: +86 553 3869303.

E-mail addresses: yhy456@mail.ahnu.edu.cn (H.-Y. Yu),

jiashanG@mail.ahnu.edu.cn (J.-S. Gu).

tion among these methods [4,5]. However, the degree of grafting

in these methods is not controllable and is often too high. As a

result, the micropores on the membrane surface were jammed;

membrane permeability was decreased after modification. This

loss of membrane permeability has been widely observed and has

been linked to the blockage of membrane pores by the grafted

polymer chains, and is deteriorated by a high grafted chain den-

sity and long chain length [6]. Grafting short polymer chains may

be one approach to improving the modified membrane perme-

ability after modification. A high grafted chain density and long

graft chain length may be essential to impart the necessary sur-

face hydrophilicity to decrease membrane fouling. Accordingly, the

graft chain density and chain length should be optimized to impart

the necessary surface hydrophilicity and improve the permeability

as high as possible. However, as a result of the traditional free rad-

ical nature of the polymerization processes it is not easy to control

molecular weight of the grafted chains or to prepare block graft-

ing chains, therefore it is difficult to design and standardize the

properties of the final product [7].

0376-7388/$ – see front matter © 2010 Elsevier B.V. All rights reserved.

doi:10.1016/j.memsci.2010.08.016

Sensors and Actuators B 150 (2010) 742–748

Contents lists available at ScienceDirect

Sensors and Actuators B: Chemical

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Multi-layer ZnO architectures: Polymer induced synthesis and their application

as gas sensors

Baoyou Geng ∗, Jun Liu, Chunhua Wang

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Laboratory of Molecular-Based Materials, Anhui Normal University,Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 10 February 2010

Received in revised form 29 July 2010

Accepted 5 August 2010

Available online 21 August 2010

Keywords:ZnO

Multi-layer

Architectures

Gas sensors

a b s t r a c t

Novel ZnO multi-layer architectures have been prepared successfully by using poly (sodium 4-

styrenesulfonate) (PSS) as structure-directing agent through hydrothermal route. The mass ratio of

reactants (Zn(CH3COO)2·2H2O and PSS) plays a critical role on the synthesis of ZnO with different struc-

tures. The as-prepared multi-layer architectures are hexagonal profiles and consist of many nanosheets

with a 120◦ angle. The thickness of these nanosheets can be controlled by the mass ratio of reactants.

The gas sensing properties of the as-synthesized ZnO multi-layer architectures are investigated in detail.

The results indicate that the obtained products exhibit superior response to acetone and ethanol, as well

as faster response/recovery times and good reproducibility. Moreover, it is believed that this polymer-

induced approach can be extended to fabricate other semiconductor materials with unique morphology

or shape.

© 2010 Elsevier B.V. All rights reserved.

1. Introduction

Over past decades, the controlled fabrication of multidimen-

sional semiconductors has attracted much attention due to their

extensive applications in many areas, such as catalysts, solar cells

and sensors [1–4]. Since the properties of these materials are highly

dependent on their size, shape, and crystalline structure, many

methods have been exploited to fabricate multidimensional archi-

tectures assembled from primary building blocks, such as capillary

effects, surface tension, templates assisted routes and so on [5–13].

One of the most promising methods is using polymers as the

structure-directing agent or template to control the nucleation,

growth, and alignment of crystals [14,15]. Especially, hydrophilic

polymers induced synthesis approaches of multidimensional archi-

tectures in liquid phase have attracted much attention in recent

years. Jimmy Yu et al. have prepared ZnO microhemispheres and

microspheres self-assembled by one-dimensional nanorods and

nanosheets with the presence of certain amount of poly (sodium

4-styrenesulfonate) (PSS) [16]. Yu and co-workers [17] have also

synthesized special mineral superstructures by diverse kinds of

hydrophilic polymers.

As a wide bandgap semiconductor (Eg = 3.37 eV at 300 K), ZnO

is a versatile and multifunctional semiconductor, which has been

∗ Corresponding author. Tel.: +86 553 3869303; fax: +86 553 3869303.

E-mail address: bygeng@mail.ahnu.edu.cn (B. Geng).

attracting extensive attention due to its wide range of applica-

tions, including photo detectors, varistors, light-emitting diodes,

nanoscale lasers, surface acoustic wave filters, gas sensors, and solar

cells [18–24]. ZnO structure possesses highly anisotropic growth

rate along the c-axis, therefore, most reports are mainly focusing

on one-dimensional (1D) ZnO nanostructures [25–32]. However,

multidimensional ZnO structures (including 2D and 3D) may pro-

vide new strategies to exploit novel properties due to their complex

architectures [33], which are now attracting much attention in

the field of materials science. Various synthetic routes of fabri-

cating multidimensional ZnO architectures have been reported

[12,33–35], but the synthesis of unique ZnO 3D stacking archi-

tectures by using hydrophilic polymer as soft template is still a

challenge.

In this paper, we report on the fabrication of novel multi-

layer architectures of ZnO by a hydrophilic polymer induced route.

The obtained multi-layer architectures consist of nanosheets and

those with a hexagonal profile. By adjusting the mass ratio of

Zn(CH3COO)2·2H2O and poly (sodium 4-styrenesulfonate) (PSS),

we can adjust the size and thickness of the nanosheets to assem-

ble different multi-layer architectures. The reaction temperature is

also an important factor for the morphology and size of products.

Moreover, detailed gas sensing measurements indicate that the

as-prepared ZnO multi-layer architectures exhibit high response

to acetone and ethanol due to their particular morphologies,

which is significant for exploiting new gas-sensing materials in the

future.

0925-4005/$ – see front matter © 2010 Elsevier B.V. All rights reserved.

doi:10.1016/j.snb.2010.08.008

Sensors and Actuators B 150 (2010) 247–253

Contents lists available at ScienceDirect

Sensors and Actuators B: Chemical

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Enhancement in analytical hydrazine based on gold nanoparticles deposited on

ZnO-MWCNTs films

Cuihong Zhanga, Guangfeng Wanga, Yulan Ji a,b, Min Liua, Yuehua Fenga, Zhidan Zhanga, Bin Fanga,∗

a School of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR Chinab Anhui College of Chinese Traditional Medicine, Wuhu 241000, PR China

a r t i c l e i n f o

Article history:Received 18 May 2010

Received in revised form 27 June 2010

Accepted 5 July 2010

Available online 13 July 2010

Keywords:MWCNTs

ZnO

Gold nanoparticle

Modified electrode

Hydrazine

a b s t r a c t

A good route (electrodeposition) for the fabrication of gold nanoparticles (nano-Au) attached on ZnO-

MWCNTs films modified glassy carbon electrodes (GCE) was proposed. ZnO-MWCNTs films are favored

for functioning as the biomimic membrane to immobilize nano-Au. The morphological characterization

of nano-Au/ZnO-MWCNTs was examined by scanning electron microscopy (SEM). The performances of

the nano-Au/ZnO-MWCNTs/GCE were characterized with cyclic voltammetry (CV), Nyquist plot (EIS) and

typical amperometric response (i–t). The potential utility of electrodes constructed was demonstrated

by applying them to the analytical determination of hydrazine concentration. The catalytic oxidation

of hydrazine has a better result on the nano-Au/ZnO-MWCNTs/GCE because of the synergistic effect of

nano-Au and ZnO-MWCNTs films. An optimized limit of detection of 0.15 �M was obtained at a signal to

noise ratio of 3 and with a fast response time (within 3 s). Additionally, the nano-Au/ZnO-MWCNTs/GCE

exhibited a wide linear range from 0.5 to 1800 �M and higher sensitivity. The ease of fabrication and

high stability of the modified electrode are the promising features of the proposed sensor.

© 2010 Elsevier B.V. All rights reserved.

1. Introduction

Hydrazine (N2H4) is widely used in industrial applications,

such as corrosion inhibitors, antioxidants, catalysts, emulsifiers,

and reducing agents; as a fuel in rocket propulsion systems; as

a starting material in the production of some insecticides, herbi-

cides, pesticides, dyestuffs, and explosive; and in the preparation

of several pharmaceutical derivatives [1–3]. However, hydrazine

is a toxic material, acute exposure can also damage the liver,

kidneys, and central nervous system in human, which must be

treated with care. Due to the reasons above, it is highly desir-

able to fabricate a reliable and sensitive analytical tool for the

effective detection of hydrazine [4]. Among several techniques,

electrochemical techniques offer the opportunity for portable,

economical, sensitive and rapid methodologies for the determi-

nation of hydrazine [5]. However, electrochemical oxidation of

hydrazine is kinetically sluggish, and a relatively high overpotential

is required at the carbon electrodes. Therefore, several approaches

have been investigated in an attempt to minimize this high overpo-

tentials problem and to increase the oxidation current response. A

variety of chemically modified electrodes, based on different elec-

∗ Corresponding author at: School of Chemistry and Materials Science, Anhui Nor-

mal University, Beijing East Road No. 1, Wuhu 241000, PR China.

Tel.: +86 553 3869302; fax: +86 553 3869303.

E-mail address: binfang 47@yahoo.com.cn (B. Fang).

trocatalytic moieties (electron-mediator species), have thus been

developed for detection of hydrazine which include the metal com-

plexes of phthalocyanine [6], porphyrins [7], hexacyanoferrates [8],

overoxidized polypyrrole [9] and a few others [10]. Recently, the

nanoparticles have been used to enhance the electron transfer rate

and to reduce the overpotential for the oxidation of hydrazine, due

to the exotic properties of nanostructures [11,12].

The II–VI semiconductor ZnO nanostructure presents itself as

one of the most promising materials for the fabrication of efficient

amperometric sensors due to extraordinary properties such as bio-

compatibility, non-toxicity, chemical and photochemical stability,

relatively higher specific-surface area, high electron communica-

tion features and electrochemical activities, and so on [13–17].

Recently, the use of ZnO nanostructures to fabricate an electro-

chemical hydrazine sensor has been reported in the literature

[1,18]. And in our previous work, we constructed a novel hydrazine

electrochemical sensor based on a carbon-nanotube-wired ZnO

nanoflower-modified electrode [19]. This allowed us to take full

advantage of the properties of multi-walled carbon nanotubes

(MWCNTs), with them not only helping to stabilize and bind the

ZnO nanoflowers onto the electrode surface but also to ensure

extremely large surface area and fast mass transport.

Due to the unique properties of gold nanoparticles, such as good

conductivity, useful electrocatalyticability and biocompatibility,

several researchers have been devoted to fabricate electrochem-

ical sensors and biosensors [20–23]. The gold nanoparticles

dispersed on various substrates have been reported, such as

0925-4005/$ – see front matter © 2010 Elsevier B.V. All rights reserved.

doi:10.1016/j.snb.2010.07.007

Fabrication and growth mechanism of three-dimensional spherical TiO2

architectures consisting of TiO2 nanorods with {110} exposed facets†

Yan Sang, Baoyou Geng* and Jie Yang

Received 26th February 2010, Accepted 11th May 2010

DOI: 10.1039/c0nr00151a

In this paper, we report on the fabrication of a novel rutile TiO2 architecture consisting of nanorods

with {110} exposed facets through a simple hydrothermal method without using any templates. An

outside-in ripening mechanism is proposed to account for the formation of the TiO2 architectures.

The formation of the TiO2 architectures can be attributed to the Ostwald step rule and highly acidic

medium. Significantly, the current method is suitable for high-yield (>98%) production of the TiO2

architectures with nearly 100% morphological yield. This research provides a facile route to fabricate

rutile TiO2 with three-dimensional microstructures based on nanounits. It is easy to realize their

industrial-scale synthesis and application because of the simple synthesis method, low cost, and high

yield.

1. Introduction

In recent years, scientists have exploited many methods to

fabricate all kinds of nanomaterials with different composition,

morphology, size and structure. However, with the development

of nanotechnology, they found that many properties are deter-

mined not only by their composition, morphology and size,1 but

also by their shape and exposed facets, which determine surface

atomic arrangement and coordination.2

As an important semiconductor, TiO2 has been extensively

investigated for a vast range of applications, including photo-

catalysis, solar cells/batteries, hydrogen sensors, and self-clean-

ing sensors, owing to its peculiar chemical and physical

behaviors.3–11 Recently, much research has focused on control-

ling the exposed facets of TiO2 nanostructures.12 TiO2 is found in

three different crystalline phases: anatase, rutile, and brookite.

Although less attention has been focused on rutile than anatase

TiO2, rutile TiO2, however, has some advantages over anatase

such as higher chemical stability, higher refractive index, and

cheaper production cost etc.13 Especially, rutile TiO2 (110) has

become the most studied oxide surface in surface science, and it is

generally used to model TiO2 catalytic properties under ultrahigh

vacuum conditions.14 Additionally, previous research has found

that partially reduced TiO2 provides an excellent prospect for

imaging chemical reactions with atomic resolution using scan-

ning tunneling microscopy.15 For the reduced rutile TiO2 (110)

surface, the bridge-bonded oxygen (BBO) vacancies are the most

common point defects. For this reason, rutile TiO2 (110) has been

widely used as a substrate for organic catalysis. For example, Hu

and co-workers studied the O2 supply pathway in CO oxidation

on Au/TiO2 (110). They found that there is a charge transfer

from TiO2 in the presence of OH to O2, and the O2 adsorption

energy depends linearly on the O2 charge.16 Li et al. studied the

correlation between bonding geometry and band gap states at

organic–inorganic interfaces based on rutile TiO2 (110).17 They

also investigated the intrinsic hydrogen diffusion on BBO rows of

TiO2 (110).18 And many other studies based on TiO2 (110) have

been performed.19 However, the previously used TiO2 (110) is the

bulk material; nanostructural TiO2 (110) should provide

a significant improvement on its properties.

In addition, previous investigations indicated that the prop-

erties of nanostructures could be tailored not only by controlling

the size and phase of the structures, but also by adjusting their

morphology. To improve their properties, various morphologies

of TiO2 nanostructures, including porous particles, fibers, tubes

and spheres, have been prepared by means of chemical or

physical methods.4–9 Moreover, three-dimensional (3D) micro/

nanoarchitectures have stimulated much attention since such

architectures combine the features of micrometer- and nano-

meter-scaled building blocks and show unique properties

different from those of the 1D structures.20 Especially, the

preparation of highly oriented rodlike crystals has been proposed

as a method to increase the effective surface area of TiO2

nanostructures, which would allow for improving their perfor-

mance.4,21 Micro- and nanostructures with highly oriented

rodlike crystals have attracted significant interest owing to their

many attractive characteristics, such as economical use of

materials and high surface area to volume ratios. As is well

known, there are few reports on oriented aggregation of single-

crystalline rutile TiO2 nanorods into 3D architectures in high

yield by a one-step reaction in solution. Considering the appli-

cations of rutile TiO2 in the field of surface science and the

chemical industry associated with its high refractive index, the

controlled fabrication of 3D TiO2 architectures with determined

phase and structure is very significant.

Here, we report a facile hydrothermal route to fabricate

uniform TiO2 architectures in high yields. The as-obtained prod-

ucts are 3D spherical architectures consisting of single-crystal

College of Chemistry and Materials Science, Anhui Key Laboratory ofFunctional Molecular Solids, Anhui Laboratory of Molecular-BasedMaterials, Anhui Normal University, Wuhu, 241000, P. R. China.E-mail: bygeng@mail.ahnu.edu.cn

† Electronic supplementary information (ESI) available: EDS pattern ofTiO2 products (Fig. S1) and XRD patterns of products obtained afterreaction at different temperatures (Fig. S2) or for different times(Fig. S3). See DOI: 10.1039/c0nr00151a

This journal is ª The Royal Society of Chemistry 2010 Nanoscale, 2010, 2, 2109–2113 | 2109

PAPER www.rsc.org/nanoscale | Nanoscale

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This journal is c The Royal Society of Chemistry 2011 Chem. Commun., 2011, 47, 6093–6095 6093

Cite this: Chem. Commun., 2011, 47, 6093–6095

Gold–platinum yolk–shell structure: a facile galvanic displacementsynthesis and highly active electrocatalytic properties for methanoloxidation with super CO-tolerancew

Long Kuai, Shaozhen Wang and Baoyou Geng*

Received 7th December 2010, Accepted 7th April 2011

DOI: 10.1039/c0cc05429a

In this communication, we prepare a Au–Pt yolk–shell structure

through a galvanic displacement strategy and explore its

electrocatalytic properties for methanol oxidation. It exhibits

high electrocatalytic activity with notable CO-tolerance.

In recent decades, numerous efforts have been made regarding

the electrocatalytic oxidation of methanol for the great

advantages and potential applications of direct methanol fuel

cells (DMFCs).1 Previous research suggests that platinum (Pt)

is an excellent electrocatalyst for DMFCs.2 But some

crucial obstacles, including self-poisoning meaning a poor

CO-tolerance,3 low Pt utilization efficiency4 and high-cost,5

limit its development in commercial applications. Therefore,

extensive research activities are being carried out to upgrade

the performance of Pt catalysts.

Various strategies have been devoted to improving the

performance of Pt catalysts. Generally, Pt catalysts are

dispersed onto various supports to enhance their catalytic

activity and increase the Pt utilization.6 Moreover, several

hollow Pt nanostructures exhibit an apparent modification of

the catalytic activity observed for other Pt catalysts.7

Very recently, porous Pt nanotubes and open-mouthed Pt

microcapsules have been reported and these display much

better catalytic activity than that of Pt/C or Pt powders.8

Nevertheless, these hollow nanostructures, like other Pt

nanostructures, also always suffer from poor CO-tolerance.

Pt-based alloys, especially Pt/Ru, have been widely developed

to enhance the CO-tolerance.9 As expected, they certainly

restrain the CO-poisoning effect to some extent. In addition,

the cost of DMFCs with these catalysts is significantly lower.

However, Pt-based alloy catalysts sometimes present lower

activity and lower efficiency than pure Pt catalysts because

their active surface is partly replaced by the less active

component. Thus, it is still a challenge to design Pt-based

catalysts with high CO-tolerance, low Pt-loading, high catalytic

activity and long-term stability.

Herein, we design a Pt-based catalyst with a unique structure

for the electrocatalytic oxidation of methanol. This is a Au–Pt

yolk–shell (Y–S) structure, obtained by a facile strategy by a

galvanic displacement reaction, similar to that reported by Xia

et al.10 Typically, the Au@Ag core–shell (C–S) structure is

fabricated by epitaxial growth of the Ag shell onto the Au

core, and the Ag shell is subsequently displaced by H2PtCl6, so

that the super thin hollow Pt shell forms naturally while the

Au core are kept inside the hollow Pt shell. The mechanism is

illustrated in Fig. 1a.

Similar structures (entitled nanorattles) have been paid

some attention due to their unique optical properties and

superior organic catalytic activity.10,11 But the advantages

for their electrocatalytic application in DMFCs are seriously

Fig. 1 (a) The formation mechanism of the Au–Pt Y–S structure;

(b) a TEM image of the Au–Pt Y–S structure, the inset is a

high-magnification image; (c) elemental mapping images; (d) cross-

sectional compositional line profiles of the marked area in (c).

College of Chemistry and Materials Science, Anhui Key Laboratoryof Functional Molecular Solids, Anhui Laboratory of Molecular-BasedMaterials, Anhui Normal university, Wuhu, 241000, P. R. China.E-mail: bygeng@mail.ahnu.edu.cn; Fax: (+86)-553-3869303w Electronic supplementary information (ESI) available: Experimentalsection, UV-vis spectra, additional figures and figure captions. SeeDOI: 10.1039/c0cc05429a

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This journal is c The Royal Society of Chemistry 2011 Chem. Commun., 2011, 47, 2447–2449 2447

Cite this: Chem. Commun., 2011, 47, 2447–2449

Simultaneous reduction–etching route to Pt/ZnSnO3 hollow polyhedralarchitectures for methanol electrooxidation in alkaline media withsuperior performancew

Han Jiang, Baoyou Geng,* Long Kuai and Shaozhen Wang

Received 13th October 2010, Accepted 2nd December 2010

DOI: 10.1039/c0cc04390g

In this communication, a simultaneous reduction–etching route is

exploited to fabricate Pt/ZnSnO3 hollow polyhedra. The hollow

ZnSnO3 polyhedron is found to act as a novel and efficient

support of Pt-based catalyst for methanol electrooxidation in

alkaline media.

According to the types of the electrolytes, direct methanol fuel

cells (DMFCs) are divided into acid and alkaline DMFCs.

Previous researches were mainly focused on the DMFC in acid

media.1 In fact, great improvements have been made recently

on the performance of the DMFC in alkaline media.2 To both

the acid and alkaline DMFCs, the noble metal platinum (Pt) is

almost an irreplaceable material as the electrode catalyst.

However, several crucial problems about the catalysts must

be resolved before the commercial application of the DMFC

can be realized, such as the self-poison on the Pt catalyst, the

low electrochemical active surface area and low utilization

efficiency of the catalysts. Thus, there have been extensive

research activities in the modification of electrode catalyst to

upgrade the performance.3

Different types of carbon materials, such as carbon black,

carbon nanotubes (CNTs), graphene are commonly used as

supports to disperse noble metallic nanoparticles.4 However,

Pt/C composite catalyst can’t effectively solve the problem of

the CO poisoning effect.5 Recent reports showed that Pt/CNT

composite catalysts could resolve the problem of the CO

poisoning effect.6 Unfortunately, the CNT is non-rigid, it will

aggregate in the course of methanol oxidation and cause the

catalyst to lose effectiveness. It was found that Pt-based alloys,

such as Pt–Ru, Pt–Sn and Pt–W etc., could enhance the

tolerance of Pt catalysts to CO efficiently and promote their

catalytic activity for methanol electrooxidation. Nevertheless,

multi-metal composite catalysts always need a complex

production process.7 Fortunately, non-carbonic materials can

also be used as the supports of Pt-based catalysts for DMFCs

in alkaline media, such as some semiconductors and

compounds which are stable in alkaline conditions. Considering

the requirements of the supports for Pt-based catalysts, the

candidates should have a good tolerable deactivation in alkaline

media, excellent electrical conductivity, large catalytic area and

a certain rigidity. Therefore, some Sn-, Mo- and W-based

compounds with special morphologies should be satisfactory

materials as the supports of Pt-based catalysts for DMFCs in

alkaline media.

Herein we find that hollow 14-faceted polyhedra of zinc

stannate (ZnSnO3) can be used as a highly efficient support

for Pt-based alkaline DMFC catalysts. Previously, we have

presented a low-cost and convenient process for the mass

synthesis of uniform octahedral, truncated octahedral, and

14-faceted polyhedral ZnSnO3 crystals.8 Here, we firstly use a

‘‘simultaneous reduction–etching route’’ to fabricate a

composite catalyst of Pt/ZnSnO3 hollow 14-faceted polyhedra

with L-ascorbic acid as reductant and the ZnSnO3 solid

14-faceted polyhedra as precursor. The obtained composite

catalyst shows an excellent electrocatalyst performance for the

alkaline DMFC. The Pt/ZnSnO3 catalyst has a remarkable

catalytic reduction current density of 16.5 mA cm�2 at �0.18 V,

and the catalyst maintains a very stable current density within

the scope of scanning. The study in the paper will shed light on

the exploitation of the novel catalysts for alkaline DMFCs in

the future.

The experimental section is shown in Supporting

Information. Fig. S1 shows the typical SEM images and

corresponding XRD patterns of the as-prepared polyhedra.

We find that the obtained ZnSnO3 solid polyhedra can be

etched by acid to form hollow polyhedra with the morphology

retained. Especially, for 14-faceted polyhedra which have

different kinds of exposed surface with different surface

energy, which makes it feasible to fabricate hollow polyhedra

with only small surface damage through an etching route.

The SEM and TEM images (Fig. 1a and b) of the as-

prepared ZnSnO3 hollow polyhedra by an acid etching route

(HCl, 1 M) reveal that the etched product retains the

morphology of the precursor. Considering the acid etching

route can be used to obtain the ZnSnO3 hollow polyhedra, we

choose L-ascorbic acid as the reductant to prepare Pt

nanoparticles, because HCl is the byproduct after L-ascorbic

acid reduces H2PtCl6, through which the reduction and etching

may happen simultaneously. As expected, the Pt/ZnSnO3

College of Chemistry and Materials Science, Anhui Key Laboratoryof Functional Molecular Solids, Anhui Laboratory of Molecular-BasedMaterials, Anhui Normal University, Wuhu, 241000, P. R. China.E-mail: bygeng@mail.ahnu.edu.cn; Fax: (+86)-553-3869303w Electronic supplementary information (ESI) available: Experimentalsection; XPS patterns, additional XRD, SEM and TEM images. SeeDOI: 10.1039/c0cc04390g

ChemComm Dynamic Article Links

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DOI: 10.1002/chem.201002949

Silver and Gold Icosahedra: One-Pot Water-Based Synthesis and TheirSuperior Performance in the Electrocatalysis for Oxygen Reduction

Reactions in Alkaline Media

Long Kuai, Baoyou Geng,* Shaozhen Wang, Yanyan Zhao, Yinchan Luo, andHan Jiang[a]

Introduction

Considerable attention has been paid to noble-metal nano-structures for their unique properties and potential applica-tions in optics,[1] surface-enhanced Raman scattering,[2] elec-trocatalysis in fuel cells,[3] organic catalysis,[4] and sensors.[5]

Because the properties and applications depend strongly onthe morphologies and sizes of the noble-metal nanostruc-tures, no effort has been spared to obtain morphology- andsize-controllable noble-metal nanostructures with the de-sired properties.[6–15] Many methods have been developedfor the preparation of noble-metal nanostructures (thesehave been summarized by Sau and Rogach[16]); namely, pre-formed-seed-mediated growth, high-temperature reduction,spatially confined medium/template approach, electrochemi-cal synthesis, photochemical methods, and biosynthesis.

Among the noble-metal nanostructures, 3D polyhedralnanostructures have attracted particular attention due to

their attractive properties in the electrocatalysis of fuelcells.[3a,15a] Thus far, much effort has been focused on acidicfuel cells, although great improvements have recently beenmade to the performance of alkaline fuel cells in fastoxygen reduction kinetics and nonplatinum-cathode cata-lysts. The kinetics of the oxygen reduction reaction (ORR)are more important in alkaline media than in acidic media,so various catalysts have been developed for use in alkalinemedia for the ORR.[17] In terms of the nonplatinum-cathodecatalyst, the relatively cheap and abundant Ag is the bestcandidate for the ORR in alkaline media due to its highelectrocatalytic activity.[3c]

Most noble-metal polyhedra have been fabricated by thepolyol process, sometimes with the help of additional pre-formed seeds[18] or ions such as Ag+ ,[9c] Cl�,[19] and S2�.[20]

These ions inevitably introduce some impurities, so that sub-sequent purification is necessary. Icosahedral noble-metalnanoparticles have attracted particular attention because oftheir highly symmetrical morphology and unique opticalproperties. Nevertheless, there are few reports on their prep-aration because of the difficulty in controlling their mor-phology and size distribution. Most of the reported icosahe-dra have been synthesized by the polyol process; water-based systems have only rarely been reported.[14c, d] More im-portantly, the methods reported to date are all limited tothe preparation of one particular icosahedral noble-metalnanostructure.

Herein, we develop a one-pot, water-based, seedless ap-proach for a high-yield synthesis of icosahedral nanoparti-

Abstract: Much effort has gone intogenerating polyhedral noble metalnanostructures because of their superi-or electrocatalytic activities for fuelcells. Herein, we report uniform, high-yield icosahedral silver and gold nano-particles by using a facile one-pot,seedless, water-based approach that in-corporates polyvinyl pyrrolidone andammonia. Electrocatalysis of theoxygen-reduction reaction was carriedout in alkaline media to evaluate theperformance of the icosahedral nano-

particles. They showed excellent stabili-ty and much higher electrocatalytic ac-tivity than the spherelike nanoparti-cles; they display a positive shift in re-duction peak potential for O2 of 0.14and 0.05 V, while the reduction peakcurrents of the silver and gold icosahe-dra are 1.5- and 1.6-fold, respectively,

better than the spherelike nanoparti-cles. More importantly, the icosahedralnanoparticles display electrocatalyticactivities comparable with commercialPt/C electrocatalysts. The facile prepa-ration of icosahedral silver and goldnanoparticles and their superior perfor-mance in the oxygen reduction reactionrender them attractive replacementsfor Pt as cathode electrocatalysts in al-kaline fuel cells.

Keywords: electrochemistry · fuelcells · gold icosahedra · hydrother-mal synthesis · silver icosahedra

[a] L. Kuai, Dr. B. Geng, Dr. S. Wang, Y. Zhao, Y. Luo, H. JiangCollege of Chemistry and Materials ScienceAnhui Key Laboratory of Functional Molecular SolidsAnhui Laboratory of Molecular-Based MaterialsAnhui Normal UniversityWuhu, 241000 (P.R. China)Fax: (+86)553-3869303E-mail : bygeng@mail.ahnu.edu.cn

Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/chem.201002949.

� 2011 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim Chem. Eur. J. 2011, 17, 3482 – 34893482

Published: July 06, 2011

r 2011 American Chemical Society 10295 dx.doi.org/10.1021/la201691c | Langmuir 2011, 27, 10295–10301

ARTICLE

pubs.acs.org/Langmuir

Single-Walled Carbon Nanotube/PyrenecyclodextrinNanohybrids for Ultrahighly Sensitive and Selective Detectionof p-NitrophenolYan Wei,†,‡,§,^ Ling-Tao Kong,§,^ Ran Yang,†,§ Lun Wang,*,† Jin-Huai Liu,§ and Xing-Jiu Huang*,§,||

†College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China‡Department of Chemistry, Wannan Medical College, Wuhu 241002, PR China§Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, PR China

)School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, PR China

’ INTRODUCTION

High active surface area, long-term stability, and high electrontransfer are of the greatest challenges facing the construction ofan electrochemical sensing interface. Thoroughly searching theliterature, carbon nanotubes (CNTs), owing to their electricalconductivity, morphology, and good chemical stability, werefound to be attractive platforms for electrode modifications.For example, carbon nanotubes are the stiffest materials knownto date and exhibit excellent electronic properties that bridgethose of the bulk and molecules.1 They readily accept electrons,which can then be transported under nearly ideal conditionsalong the axis. Previously, we have chosen carbon nanotubes as acandidate to make electrochemical sensors. For instance, westudied the electrochemical behavior of needlelike and forestlikesingle-walled carbon nanotube (SWCNT) electrodes.2 We alsomade some CNT nanocomposites, such as ferrocene function-alized SWCNT bundles,3 enzyme modified SWCNT/ferrocenehybrids,4 and chestnutlike hierarchical architecture of SWCNT/polystyrene microsphere composites,5 for electrochemical sen-sing applications.

Recently, new hybrid materials based on CNT and pyrenehas been developed as electron donor�acceptor nano-composites.1,6,7 The self-assembly approach does not formany covalent bonds but only π�π interactions and perturbsweakly the nanotube conjugated system. Pyrene derivatives

with a large variety of functional groups can be easily preparedso that the approach is very general and easy to exploit. Workperformed at electrode surfaces demonstrated that the presenceof extended, delocalized π-electron systems is, indeed, veryuseful in terms of charge transfer and charge transport.8 Thesesystems have been demonstrated to prepare practical photo-electrochemical devices6 or field-effect transistors.9

Very recently, we have pursued this strategy to prepareSWCNT/pyrenecyclodextrin (PyCD) nanohybrids and detectpolychlorinated biphenyl (PCB), that is, 3,30,4,40-tetrachlorobi-phenyl (PCB-77), using electrochemcial impedance technique.10

In contrast to the case of redox reaction-based electrochemicalmethods, when the PCB-77 as hydrophobic guest moleculeswere included in the cavities of the PyCD hosts, the formation ofguest�host complexes could create a barrier for the electro-chemical process, thereby hindering the access of the redox probe(Fe(CN)6

3-/4-) to the electrode surface, resulting in an increasein the electron-transfer resistance. As such, it should be anindirect method.

p-Nitrophenol (4-nitrophenol; P-NP or 4-NP) is one of theseverely toxic substituted phenols. P-NP induces methemoglobin

Received: May 6, 2011Revised: June 15, 2011

ABSTRACT: Electrochemical detection of p-nitrophenol (P-NP) using a highly sensitive and selective platform based onsingle-walled carbon nanotube/pyrenecyclodextrin (SWCNT/PyCD) nanohybrids is described for the first time. The electro-chemical performance of the SWCNT/PyCD nanohybridelectrode was fully compared with bare glassy carbon, single-SWCNT, single-PyCD, and SWCNT/CD (without pyrenerings) electrodes. Besides the techniques of cyclic voltammetryand chronoamperometric transients, differential pulse voltam-metry (DPV) has been used for the detection of P-NP withoutany interference from o-nitrophenol (O-NP) at the potentials of�0.80 and �0.67 V, respectively. The SWCNT/PyCD nano-hybrid electrode is highly sensitive, and it shows an ultrahigh sensitivity of 18.7 μA/μM toward P-NP in contrast to the valuesreported previously. The detection limit (S/N = 3) of the SWCNT/PyCD nanohybrid electrode toward P-NP is 0.00086 μM (0.12ppb), which is well below the allowed limit in drinking water, 0.43 μM, given by the U.S. Environmental Protection Agency (EPA).The analytical performance of the SWCNT/PyCD nanohybrid electrode toward P-NP is superior to the existing electrodes.

Single-crystalline a-Fe2O3 oblique nanoparallelepipeds: High-yield synthesis,growth mechanism and structure enhanced gas-sensing properties

Xuelian Li, Wenjing Wei, Shaozhen Wang, Long Kuai and Baoyou Geng*

Received 21st August 2010, Accepted 30th September 2010

DOI: 10.1039/c0nr00617c

In this paper, single-crystalline a-Fe2O3 oblique nanoparallelepipeds are fabricated in high yield via

a facile surfactant-free hydrothermal method, which involves oriented aggregation and Ostwald

ripening. The obtained nanocrystals have exposed facets of {012}, {01–4} and {�210} with

a rhombohedral a-Fe2O3 structure. The gas sensors based on the as-synthesized a-Fe2O3

nanostructures exhibit high sensitivity, short recovery time, and good reproducibility in ethanol and

acetone. The superiority of the gas-sensing properties of the obtained nanostructures should be

attributed to the surface structure of the nanocrystals. The as-prepared a-Fe2O3 nanocrystals are

significant for exploiting their other applications in the future.

1. Introduction

Controlled fabrication of micro/nanostructures has attracted

tremendous attention because of their intriguing size/shape-

dependent properties. Correspondingly, many techniques have

been exploited in the fabrication of various shapes of micro/

nanostructures, such as rods, wires, tubes and polyhedra.1–5

As an important n-type semiconductor, hematite (a-Fe2O3) is

the most stable iron oxide under ambient conditions, and has

been extensively used as gas sensors, catalysts, and pigments due

to its low cost, non-toxicity and high resistance to corrosion.6–8 In

recent years, stimulated by the promising applications of iron

oxides and the novel properties of nanomaterials, much effort

has been made to synthesize a-Fe2O3 with various morphologies,

such as nanoparticles, nanorods, nanowires, and nanotubes.6–9

As expected, the diverse a-Fe2O3 morphologies led to intriguing

shape-dependent properties and varied potential applications.6,10

Especially, a-Fe2O3 has been found to be used as an efficient gas-

sensing material due to its electrical conductivity that is highly

sensitive to the gaseous environment.11 As is well known, most of

the metal oxide based sensors operate at elevated temperatures in

the range 150–160 �C. However, long-term use of the sensor at

high temperatures might degrade its structural properties or, in

some cases, lead to irreversible changes in the phase of the sensor

material.12 Therefore, it is necessary to exploit good performance

and relatively stable metal oxides for gas sensors. Hematite is the

most appropriate candidate for gas sensors due to its structural

stability, low cost and non-toxicity.

So far, some efforts have been made to study the gas sensitivity

ofa-Fe2O3with variousmorphologies. For example, JimmyC.Yu

and co-workers fabricated a-Fe2O3 nanorings through a wave-

assisted hydrothermal process. They found that the thin film

sensor made of the a-Fe2O3 nanorings exhibited high sensitivity

and good reversibility for gas-sensing of alcohol under ambient

conditions.6 Guoxiu Wang et al. reported a surfactant-free

hydrothermal process to synthesize thea-Fe2O3 bamboo flute-like

porous nanorods and hexapod-like nanostructures with subse-

quent calcination of the obtained precursors. The obtained

materials have been used to detect ethanol, acetone and gasoline.8

Liu and Zhang et al. reported on the synthesis of a-Fe2O3 nano-

tubes through a carbon nanotube template process. The as-

prepared a-Fe2O3 nanotubes exhibited superior sensitivity to

hydrogen sulfide (H2S) based on the catalytic chemiluminescence

(CL).13M.V. Reddy and his co-workers used a thermal treatment

method to prepare nanoflakes of a-Fe2O3 on Cu foil and so on.14

Despite these achievements, the variety of shapes of a-Fe2O3

nanocrystals still needs to be greatly expanded to meet their

growing applications. Particularly, considerable recent

researches have focused on the synthesis of different shapes of

micro/nanostructural polyhedra, such as cubes, octahedra,

dodecahedra, 14-facets polyhedra, icosahedra etc. because of

their shape-related potential applications in many fields, such as

gas sensors, optics, catalysts, electrode materials and so on.6–10

As a rhombohedral structure of a-Fe2O3, fabrication of its

nanocrystals with a defined shape, especially with special exposed

facets that would bring with it high and special activities, might

exploit its novel applications and widen its application ranges.15

For example, Rodriguez et al. found that the thermolysis of

acidic ferric chloride could lead to monodispersed hematite

nanocrystallites of rhombohedral shape with facets belonging to

the {104} family.16 Very recently, Gao and co-workers reported

on the synthesis of unusual tetrakaidecahedral and oblique

parallelepiped iron oxide nanocrystals with exposed high index

facets, which was found to exhibit unusual magnetic properties.17

To enrich the research in this area, herein, we exploit a facile

surfactant-free hydrothermal method to fabricate a-Fe2O3 with

a special oblique parallelepiped morphology, which involves

oriented aggregation and Ostwald ripening. The obtained

a-Fe2O3 nanocrystals have exposed facets of {012}, {01–4} and

{�210}, which makes it possible to facilitate their applications.

Correspondingly, the obtained nanostructures have been fabri-

cated into gas sensors and used to detect some gases such as

ethanol and acetone. The results show that the gas sensors based

on the as-synthesized a-Fe2O3 nanostructures exhibit high

College of Chemistry and Materials Science, Anhui Key Laboratory ofFunctional Molecular Solids, Anhui Laboratory of Molecular-BasedMaterials, Anhui Normal University, Wuhu, 241000, P. R. China.E-mail: bygeng@mail.ahnu.edu.cn

718 | Nanoscale, 2011, 3, 718–724 This journal is ª The Royal Society of Chemistry 2011

PAPER www.rsc.org/nanoscale | Nanoscale

DOI: 10.1021/jo1020773 Published on Web 12/13/2010 J. Org. Chem. 2011, 76, 229–233 229r 2010 American Chemical Society

pubs.acs.org/joc

AlCl3-Promoted Highly Regio- and Diastereoselective [3 þ 2]Cycloadditions of Activated Cyclopropanes and Aromatic Aldehydes:Construction of 2,5-Diaryl-3,3,4-trisubstituted Tetrahydrofurans

Gaosheng Yang,* Yue Shen, Kui Li, Yongxian Sun, and Yuanyuan Hua

Anhui Key Laboratory of FunctionalMolecular Solids, Institute of Organic Chemistry, College of Chemistryand Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China

gshyang@mail.ahnu.edu.cn

Received October 20, 2010

TheAlCl3-catalyzed [3þ 2] cycloaddition reaction of diethyl trans-2,3-disubstituted cyclopropane-1,1-dicarboxylates and aromatic aldehydes was carried out under mild conditions to provide a series ofdiethyl 2,5-diaryl-4-benzoyltetrahydrofuran-3,3-dicarboxylates in moderate to good yields withexcellent diastereoselectivities. While common 2,5-cis products were obtained with electron-neutralor electron-poor aryl aldehydes, the much less common 2,5-trans products were obtained in excellentdiastereoselectivities when electron-rich aryl aldehydes were used. The relative configurations ofthose typical products were confirmed by X-ray crystallographic analyses.

Introduction

Substituted tetrahydrofurans are an important structuralmotif present in numerous natural products with a widerange of diverse biological and pharmacological activities.1

Consequently, the synthesis of these substituted tetrahy-drofurans has received an intense interest among organic

chemists, and plenty of elegantmethods have been developedfor this purpose.2 Among those, the Lewis acid-catalyzed[3 þ 2] cycloadditions of aldehydes/ketones with activateddonor-acceptor (D-A) cyclopropanes are particularly attrac-tive due to their good atomic economy and easy availabilityof the starting materials.3-6 Johnson and co-workers havedeveloped highly diastereoselective,4b,c enantiospecific,4a

and enantioselective4e Lewis acid-catalyzed intermolecular[3þ 2] cycloadditions of aldehydes with carbon-based donorD-A cyclopropanes, and have applied it for the totalsynthesis of (þ)-Polyanthellin A7 and (þ)-virgatusin.8 Lately,Wang and co-workers reported a related intramolecularversion of this reaction to construct complex oxa-[n.2.1]

*To whom correspondence should be addressed. Phone: þ86 05533869310. Fax: þ86-0553-3883517

(1) (a) Ward, R. S.Nat. Prod. Rep. 1997, 14, 43–74. (b) Saleem, M.; Kim,H. J.; Ali, M. S.; Lee, Y. S.Nat. Prod. Rep. 2005, 22, 696–716. (c) Pan, J.-Y.;Chen, S.-L.; Yang, M.-H.; Wu, J.; Sinkkonen, J.; Zou, K. Nat. Prod. Rep.2009, 26, 1251–1292. (d) Gautam, R.; Jacbak, S.M.Med. Res. Rev. 2009, 29,767–820. (e) Carvalho, A. A. V.; Galdino, P. M.; Nascimento, M. V. M.;Kato, M. J.; Valadares, M. C.; Cunha1, L. C.; Costa, E. A. Phytother. Res.2010, 24, 113–118. (f) Seo, C.-S.; Lee, W.-H.; Chung, H.-W.; Chang, E. J.;Lee, S. H.; Jahng, Y.; Hwang, B. Y.; Son1, J.-K.; Han, S.-B.; Kim, Y.Phytother. Res. 2009, 23, 1531–1536. (g) Nguyen, P. H.; Le, T. V. T.; Kang,H. W.; Chae, J.; Kim, S. K.; Kwon, K.; Seo, D. B.; Lee, S. J.; Oh, W. K.Bioorg. Med. Chem. Lett. 2010, 20, 4128–4131.

(2) (a)Wolfe, J. P.; Hay,M. B.Tetrahedron 2007, 63, 261–290. (b)Yamauchi,S.; Nakato, T.; Tsuchiya, M.; Akiyama, K.; Maruyama, M.; Sugahara, T.;Kishida, T. Biosci. Biotechnol. Biochem. 2007, 71, 2248–2255. (c) Martinet, S.;M�eou,A.; Brun, P.Eur. J.Org.Chem. 2009, 2306–2311. (d)Moinuddin, S.G.A.;Hishiyama, S.; Cho,M.-H.; Davin, L. B.; Lewis, N.G.Org. Biomol. Chem. 2003,1, 2307–2313. (e) Yamauchi, S.; Okazaki, M.; Akiyama, K.; Sugahara, T.;Kishida, T.; Kashiwagi, T. Org. Biomol. Chem. 2005, 3, 1670–1675. (f) Jahn,U.; Rudakov, D. Org. Lett. 2006, 8, 4481–4484. (g) Kim, H.; Wooten, C. M.;Park, Y.; Hong, J. Org. Lett. 2007, 9, 3965–3968. (h) Matcha, K.; Ghosh, S.Tetrahedron Lett. 2008, 49, 3433–3436. (i) Campbell, M. J.; Johnson, J. S.;Parsons, A. T.; Pohlhaus, P. D.; Sanders, S. D. J. Org. Chem. 2010, 75, 6317–6325. (j) Karadeolian, A.; Kerr, M. A. J. Org. Chem. 2010, 75, 6830–6841.

(3) Christie, S.D.R.; Davoile, R. J.; Elsegood,M.R. J.; Fryatt, R.; Jones,R. C. F.; Pritchard, G. J. Chem. Commun. 2004, 2474–2475.

(4) (a) Pohlhaus, P. D.; Johnson, J. S. J. Am. Chem. Soc. 2005, 127,16014–16015. (b) Pohlhaus, P. D.; Johnson, J. S. J. Org. Chem. 2005, 70,1057–1059. (c) Parsons, A. T.; Campbell, M. J.; Johnson, J. S. Org. Lett.2008, 10, 2541–2544. (d) Pohlhaus, P. D.; Sanders, S. D.; Parsons, A. T.; Li,W.; Johnson, J. S. J. Am. Chem. Soc. 2008, 130, 8642–8650. (e) Parsons,A. T.; Johnson, J. S. J. Am. Chem. Soc. 2009, 131, 3122–3123.

(5) Gupta, A.; Yadav, V. K. Tetrahedron Lett. 2006, 47, 8043–8047.(6) (a)Xing, S.; Pan,W.; Liu, C.; Ren, J.;Wang, Z.Angew.Chem., Int. Ed.

2010, 49, 3215–3218. (b) Hu, B.; Xing, S.; Ren, J.; Wang, Z. Tetrahedron2010, 66, 5671–5674.

(7) Campbell, M. J.; Johnson, J. S. J. Am. Chem. Soc. 2009, 131, 10370–10371.

(8) Sanders, S. D.; Ruiz-Olalla, A.; Johnson, J. S. Chem. Commun. 2009,5135–5137.

Regioselective Stepwise Bromination of Boron Dipyrromethene(BODIPY) DyesLijuan Jiao,* Weidong Pang, Jinyuan Zhou, Yun Wei, Xiaolong Mu, Guifeng Bai, and Erhong Hao*

Laboratory of Functional Molecular Solids, Ministry of Education; Anhui Laboratory of Molecule-Based Materials; School ofChemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, China

*S Supporting Information

ABSTRACT: Halogenated BODIPYs are important synthetic precursors andpotential sensitizers for photodynamic therapy (PDT). Electrophilic bromination ofpyrrolic-unsubstituted BODIPYs using bromine regioselectively generated mono- toheptabromoBODIPYs in a stepwise fashion in good to excellent yields. Theseresultant bromoBODIPYs were applied for regioselective substitution and Suzukicoupling reaction to generate BODIPYs 4, 5, 6, and 7 in good to excellent yields.According to NMR and X-ray analysis results, the stepwise bromination first takes place at 2,6-, then at 3,5-, and eventually at 1,7-positions, whereas the regioselective substitution occurs first at 3,5- then at 1,7-positions of the chromophore. The spectroscopicproperties of these resultant BODIPYs were studied, which shows the potential application of these bromoBODIPYs assensitizers for PDT.

■ INTRODUCTIONThe wide application of fluorescent dyes has led to theincreased research interest in these molecules lately, especially4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes, also known asBODIPYs.1−6 BODIPYs have found wide applications indiverse fields, for example, as labeling reagents,7,8 chemo-sensors,9−11 and energy transfer cassettes,12−15 due to theirremarkable properties, including large molar absorptioncoefficient, sharp fluorescence emissions, high fluorescencequantum yields, and high photophysical stability.Postmodification16−23 of some ready-made BODIPY frame-

works (such as halogenated BODIPYs A and B shown in Figure

1) is a convenient avenue for the facile functionalization ofBODIPYs. Among those, 3,5-chlorinated BODIPYs (A with X= Cl), first developed by Boens et. al24 via total synthesis, havebeen used for SNAr and palladium-catalyzed cross-couplingreactions to generate the corresponding mono- and disub-stituted BODIPYs.25−34 As complementary to Dehaen andBoens’s chlorinated BODIPYs, our group35−37 recently hasdeveloped 3-chloro- and 3,5-diiodoBODIPYs from the BF3

complexation of the corresponding halogenated dipyrrome-thenes. 2,6-Halogenated BODIPYs B38 are potential sensitizersfor photodynamic therapy (PDT) using the heavy atom effectof these halogen atoms39−45 and have also found wideapplications in the construction of many interesting mole-

cules,46−52 including long wavelength fluorescent dyes.However, it is hard to control the halogen regiochemistry inthese halogenated BODIPYs. It is achieved either through thehalogenation of the key synthetic precursor of BODIPY(dipyrromethanes) during the course of BODIPY totalsynthesis, or through the blocking effects of 1,3,5,7-tetraalkyl-substituents. No direct regioselective halogenation on BODIPYhas been achieved until the recent disclosure of tetra- andhexabromoBODIPYs by Churchill and co-workers53 and of 2,6-dibromoBODIPYs by Shinokubo and co-workers.54 The firstcase is achieved from the bromination of meso-thienyl BODIPYusing bromine, and the second one is obtained using N-bromosuccinimide (NBS) at −78 °C. Therefore, theregioselective halogenation of pyrrolic-unsubstituted BODIPYslike 1a (Scheme 1) remains a challenge.Inspired by recent reports of the iridium-catalyzed

regioselective β-borylation of BODIPY 1a by Osuka55 andregioselective nucleophilic substitution of BODIPY 1a byDehaen and Boens,56,57 respectively, herein we report thepreparation of mono- to heptabromoBODIPYs from theregioselective stepwise bromination of pyrrolic-unsubstitutedBODIPYs 1 using bromine and the subsequent application ofthese resultant bromoBODIPYs for the regioselective nucleo-philic substitution and Suzuki coupling reactions. The stepwisebromination was achieved through the variation of the amountof bromine and the reaction time. As shown by NMR and X-rayanalysis results, this stepwise bromination first took place at 2,6-, then at 3,5-, and eventually at 1,7-positions, whereas theregioselective nucleophilic substitution occurred first at 3,5-then at 1,7-positions of the chromophore.

Received: August 22, 2011Published: November 13, 2011

Figure 1. Chemical structures of halogenated BODIPYs A and B.

Article

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© 2011 American Chemical Society 9988 dx.doi.org/10.1021/jo201754m | J. Org. Chem. 2011, 76, 9988−9996

A DNA hybridization detection based on fluorescence resonance energytransfer between dye-doped core-shell silica nanoparticles and goldnanoparticles

Feng Gao,* Peng Cui, Xiaoxiao Chen, Qingqing Ye, Maoguo Li and Lun Wang

Received 8th April 2011, Accepted 24th June 2011

DOI: 10.1039/c1an15287d

A novel and efficient method to evaluate the DNA hybridization based on a fluorescence resonance

energy transfer (FRET) system, with fluorescein isothiocyanate (FITC)-doped fluorescent silica

nanoparticles (SiNPs) as donor and gold nanoparticles (AuNPs) as acceptor, has been reported. The

strategy for specific DNA sequence detecting is based on DNA hybridization event, which is detected

via excitation of SiNPs-oligonucleotide conjugates and energy transfer to AuNPs-oligonucleotide

conjugates. The proximity required for FRET arises when the SiNPs-oligonucleotide conjugates

hybridize with partly complementary AuNPs-oligonucleotide conjugates, resulting in the fluorescence

quenching of donors, SiNPs-oligonucleotide conjugates, and the formation of a weakly fluorescent

complex, SiNPs-dsDNA-AuNPs. Upon the addition of the target DNA sequence to SiNPs-dsDNA-

AuNPs complex, the fluorescence restores (turn-on). Based on the restored fluorescence,

a homogeneous assay for the target DNA is proposed. Our results have shown that the linear range for

target DNA detection is 0–35.0 nM with a detection limit (3s) of 3.0 picomole. Compared with FITC-

dsDNA-AuNPs probe system, the sensitivity of the proposed probe system for target DNA detection is

increased by a factor of 3.4-fold.

Introduction

As the human genome project has unveiled the full sequence of

human genomes, and postgenome technologies have been

rapidly developed, sequence-specific DNA detection—which is

of extreme importance in clinical molecular diagnostics of

diseases, gene therapy, biomedical studies, fast detection of

biological warfare agents, and forensic applications—has

attracted more and more attention.1–4 Generally, sequence-

specific DNA detection is achieved by DNA hybridization.1,5–9

A variety of approaches, including electrochemical and also

optical and gravimetric detection modes, have been developed

to read the DNA hybridization events and thus detect specific

DNA sequences.10–28 Among these proposed methods, fluores-

cence-based assays offer many advantages such as increased

sensitivity, safety and multiplexing capabilities, as well as the

ability to measure multiple fluorescence properties.5,7,15–28 A

number of these fluorescence-based assays rely on fluorescence

resonance energy transfer (FRET) spectroscopic technique,15–28

which occurs when the emission spectrum of the donor and the

absorption spectrum of the acceptor is overlapped to a certain

extent. FRET could be conveniently used for the design of

novel DNA sensing. Most of these FRET-based DNA bio-

sensing systems are primarily based on the use of fluorescence

from organic fluorophores, which are used to signal the

hybridization achieved directly by coupling fluorophores to the

DNA probes.15–26 However, most organic fluorophores suffer

from photobleaching, random on/off emissions (blinking), and

poor stability in the ambient environment, which results in

irreproducible fluorescence signals for analysis.27,28 In addition,

one DNA probe can only be coupled with one or a few fluo-

rophores, reducing relatively low signal intensities and as such

limited sensitivity.28 To overcome these shortcomings, some

types of nanomaterials, including quantum dots, metal nano-

particles and so on,12,13,25,29,30 have been used as signalling

probes. However, these developed methods still suffer from

some drawbacks. For example, the luminescent properties of

quantum dots are highly dependent on their size and shape,

making these materials difficult to achieve homogeneous and

consistent DNA hybridization. On the other hand, the routine

application of quantum dots is still controversial due to the

relatively high toxicity.26

Fluorophore-doped silica nanoparticles (SiNPs) have also

been used for imaging and bioanalysis in recent years.31–53

These nanoparticles, which use silica as shell and fluorophores

as core, possess some distinct advantages. For example, a single

nanoparticle contains a large number of fluorophores, which

Key Laboratory of Chemo/Biosensing, Anhui Province, Key Laboratory ofFunctional Molecular Solids, Ministry of Education, College of Chemistryand Materials Science, Anhui Normal University, Wuhu, 241000, China.E-mail: fgao@mail.ahnu.edu.cn; Fax: +86-553-3869302; Tel: +86-553-3869302

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Porous Cu–NiO modified glass carbon electrode enhanced nonenzymaticglucose electrochemical sensors†

Xiaojun Zhang,*a Aixia Gu,a Guangfeng Wang,ab Yan Huang,a Huiqing Jia and Bin Fang*a

Received 28th August 2011, Accepted 29th September 2011

DOI: 10.1039/c1an15784a

Porous Cu–NiO nanocomposites were successfully prepared by calcination of the Cu–Ni(OH)2precursor at 400 �C for 2 h. During the process of calcination, Ar was used to deaerate O2. The structure

and morphology of Cu–NiO were characterized by X-ray diffraction spectrum (XRD), energy

dispersive X-ray analyses (EDX), transmission electron microscopy (TEM), and scanning electron

microscopy (SEM). Using porous Cu–NiO nanocomposites, a simple non-enzymatic amperometric

sensor has been fabricated (Cu–NiO/GCE) and evaluated by electrochemical impedance spectroscopy

(EIS), cyclic voltammetry (CV) and typical amperometric method. When applied to detect glucose by

the amperometric method, Cu–NiO/GCE produced an ultrahigh sensitivity of 171.8 mA mM�1, with

a low detection limit of 0.5 mM (S/N ¼ 3). What’s more, interference from common co-existing species,

such as UA, AA, and fructose can be avoided at the sensor. Results in this study imply that porous

Cu–NiO nanocomposites are promising nanomaterials for the enzyme-free determination of glucose.

1. Introduction

Mesoporous nanomaterials possess unique properties, for

example, high specific surface areas, uniform systems of pores

and crystalline pore walls at nanoscale dimension.1,2 The favor-

able properties bode well for applications in different areas of

science and industry, such as catalysis, adsorption, biomolecular

separation, drug delivery, etc.3–6

As a p-type wide-band gap semiconductor, nickel oxide (NiO)

has been under extensive investigations and has diverse appli-

cations in catalysts,7 electrode materials for lithium ion batteries

and fuel cell,8 electrochromic films,9 and dye-sensitized photo-

cathodes.10 For the wide applications of NiO, it is worthwhile to

synthesize mesoporous NiO with a relatively large surface area

and crystalline walls. Wang’s group synthesized mesoporous

nickel oxide nanoplatelets by calcining the b-Ni(OH)2 at 400�C

for 2 h.8 Jiao and his co-workers prepared ordered mesoporous

NiO with crystalline walls through hard templating.11 Yuan et al.

reported the synthesis and self-assembly of hierarchical porous

NiO nano/micro spherical superstructures from the precursor,

b-Ni(OH)2, by a simple calcination procedure.12 Most of the

studies aimed at applications in catalysts,7 magnetization

measurements,11 and capacitance of the mesoporous NiO.12

Nevertheless, the application of mesoporous NiO in electro-

chemical sensors has not been referred to. The porous structure

may be in favor of its application in electrochemical sensors.

Very recently, aligned nanoarrays of several metal oxides

directly grown on conducting substrates are of special interests

because the resultant products are feasible in some special

applications.13 For examples, quasialigned ZnS nanowire arrays

have been synthesized directly on zinc substrates by Qian and his

co-workers,14 Liu described the growth of vertically oriented

TiO2 nanotube arrays on Ti meshes,15 and preparation of a large-

scale vertical array of single-crystalline CuO nanowires on ITO

surfaces is demonstrated by Ali Umar et al.16 Our group has

successfully constructed some electrochemical sensors based on

Cu–CuO and Cu–Ag2O nanomaterials. The satisfying properties

of these sensors have been acquired. It is estimated that the

improved electrochemical performance might be due to the

electric Cu substrate.17,18 Considering the potential of meso-

porous NiO as electrochemical sensor materials, inspired by

previous work, we prepared porous NiO nanoplates grown on

a Cu substrate to fabricate a new electrochemical sensor for the

first time.

It is no doubt that reliable and fast monitoring of glucose in

the fields of biotechnology, clinical diagnostics and food industry

is vital. Over the past few decades, great attention has been paid

to the development of electrochemical glucose sensors. The

sensors based on glucose oxidase (GOx) are classical glucose

sensors because they are highly sensitive and selective.19,20

However, the enzymatic glucose sensors suffer greatly from the

fatal drawback of poor stability due to the intrinsic nature of

enzymes. To solve this problem, non-enzymatic sensors based on

aCollege of Chemistry and Materials Science, Anhui Key Laboratory ofFunctional Molecular Solids, Anhui Key Laboratory ofChem–Biosensing, Anhui Normal University, Wuhu, 241000, P R China.E-mail: zhangxiaojun173@yahoo.com.cn; Fax: +86-553-3869303; Tel:+86-553-3869303bAnhui Key Laboratory of Controllable Chemistry Reaction & MaterialChemical Engineering, HeFei University of Technology, Hefei, 230009,P R China

† Electronic supplementary information (ESI) available. See DOI:10.1039/c1an15784a

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Layer-by-layer assembly and electrochemical study of a 4-aminothiophenoland ytterbium(III) trifluoromethanesulfonate hydrate film on a gold electrode

Yan Wei,abc Ran Yang,ac Xiang-Zi Li,b Lun Wang*a and Xing-Jiu Huang*cd

Received 11th April 2011, Accepted 1st July 2011

DOI: 10.1039/c1an15299h

We report on the layer-by-layer assembly and electrochemical properties of 4-aminothiophenol

(P-ATP) and ytterbium(III) trifluoromethanesulfonate hydrate (Yb(OTf)3) film supported on a gold

surface. The fabricated film was characterised electrochemically using redox couples Fe(CN)63�/4�,

complemented with imaging using atomic force microscopy (AFM). The electrocatalytic activity of the

prepared electrodes was studied using cyclic and differential pulse voltammetries. Electrochemical

measurements show that the P-ATP/Yb(OTf)3 modified electrode has superb activity towards

hydroquinone (HQ) oxidation and that there is a significant improvement in the electrode stability and

reproducibility due to the covalent and coordination reactions.

1. Introduction

Modified electrodes have been attracting explosive interest in

electrochemical studies because of the many unique properties

that they are supposed to have after introducing modifiers, or,

most importantly, because one can choose modifiers according to

the requirements of their end applications.1–10 Particularly,

besides the experimental results, Compton et al. proposed

a model for the redox process simulating voltammetry and

analyzing the electron transfer kinetics at an electrode modified

with a conducting porous film.2,11,12 A main challenge to the

preparation of modified electrodes is to find an effective coupling

of the catalytic component (i.e., high electron transfer) to the

target molecules bound to a solid surface (i.e., the stability of the

modified electrode). Among the various methods, the layer-by-

layer assembly technique is a most popular approach which is

based on the alternating adsorption of materials containing

complementary charged or functional groups to form integrated

ultrathin films.13–16 This method provides a powerful tool for

nano- and microscale assembly of devices and novel material

systems.17

There is a considerable research effort motivated towards the

determination of dihydroxybenzene isomers using modified

electrodes. Typically, graphene,18 poly(glutamic acid),19 1-butyl-

3-methylimidazolium hexafluorophosphate (ionic liquid,

BMIMPF6),20 mesoporous carbon CMK-3,21 amino-functional-

ized SBA-15 mesoporous silica,22 multi-walled carbon nanotubes

(MWCNTs),23 poly-amidosulfonic acid and MWCNTs

composite film,24 BMIMPF6 and MWCNTs composite film,25

etc, have been used as modifiers. Although these approaches

have been used to produce some outstanding results, electrode

modification remains challenging because these methods still

have disadvantages. For example, the MWCNTs-based prepa-

ration suffers from a difficulty in dispersing it into a homoge-

neous solution; the graphene-modified electrode poses another

problem in the preparation (e.g., monolayer or multilayer) and

purification of graphene.

In this study, we prepare a 4-aminothiophenol (P-ATP) and

ytterbium(III) trifluoromethanesulfonate hydrate (Yb(OTf)3) film

using layer-by-layer assembly on a gold electrode. The first

P-ATP monolayer is based on covalent self-assembly of alka-

nethiols on a gold surface.26–30 Yb(OTf)3 is formed on a P-ATP

layer by a coordination reaction between the amine group of

P-ATP and Yb(III). The P-ATP/Yb(OTf)3 film shows an excel-

lent catalytic activity towards hydroquinone (HQ) and exhibits

a good selectivity. We further studied the stability and repro-

ducibility of the P-ATP/Yb(OTf)3 film.

2. Experimental

Chemical reagents

4-Aminothiophenol (P-ATP) and ytterbium(III) tri-

fluoromethanesulfonate hydrate (Yb(OTf)3) were purchased

from Sigma-Aldrich. Hydroquinone (HQ), catechol (CC), and

resorcinol (RC) were obtained from Sinopharm Chemical

Reagent Lo., Ltd. All other chemicals were of analytical grade.

Ultrapure fresh water was obtained from a Millipore water

purification system (MilliQ, specific resistivity >18 MU cm, S.A.,

aCollege of Chemistry and Materials Sciences, Anhui Normal University,Wuhu, 241000, PR China. E-mail: wanglun@mail.ahnu.edu.cnbDepartment of Chemistry, Wannan Medical College, Wuhu, 241002, PRChinacInstitute of Intelligent Machines, Chinese Academy of Sciences, Hefei,230031, PR China. E-mail: xingjiuhuang@iim.ac.cn; Fax: +86-551-5592420; Tel: +86-551-5591142dSchool of Mechanical and Electronic Engineering, Wuhan University ofTechnology, Wuhan, 430070, PR China

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FULL PAPER

DOI: 10.1002/ejoc.201100736

α-/β-Formylated Boron–Dipyrrin (BODIPY) Dyes: Regioselective Synthesesand Photophysical Properties

Changjiang Yu,[a] Lijuan Jiao,*[a] Hao Yin,[b] Jinyuan Zhou,[a] Weidong Pang,[a]

Yangchun Wu,[a] Zhaoyun Wang,[a] Gaosheng Yang,[a] and Erhong Hao[a]

Keywords: BODIPY / Fluorescence / Dyes/pigments / Synthetic methods

Formylation has been performed on pyrrole-unsubstituteddipyrromethanes 1 and boron–dipyrrin (BODIPY) dyes 4based on a Vilsmeier–Haack reaction. It is highly regioselec-tive and complementary and occurs exclusively at the α- andβ-position, respectively, for pyrrole-unsubstituted dipyrro-methanes 1 and BODIPY dyes 4. This regioselective for-

Introduction

Boron–dipyrrin (BODIPY) dyes have been widely usedas bright fluorescent dyes for cellular imaging due to theirremarkable photophysical properties, such as photostability,large extinction coefficients and high fluorescent quantumyields.[1,2] Recent improvements in functionalization meth-ods for BODIPY has allowed fine-tuning of the propertiesof the chromophore and brought renewed research interestin BODIPYs for diverse fields, such as chemosensors,[3,4]

long-wavelength absorbing/emitting fluorescent dyes,[5–8] la-ser dyes,[9] photosensitizers,[10] sensitizers for solar cells,[11]

energy-transfer cassettes,[12] light harvesters[13] and fluores-cent organic devices.[14]

Post-modification methods on some ready-made BOD-IPY frameworks are convenient for preparing α- and β-functionalized BODIPYs (Figure 1). Of these compounds,α-functionalized BODIPYs are often achieved by Knoeven-agel condensation,[3a,3b,6] Sonogashira/Suzuki coupling[3g,5]

or oxidative formylation.[15] Functionalization at the β-posi-tion is mainly achieved by sulfonation,[16] nitration,[17] pal-ladium-catalyzed C–H functionalization,[18] and halogena-tion reactions.[5e,10] Recently, our group has reported the

[a] Laboratory of Functionalized Molecular Solids, Ministry ofEducation, and Anhui Key Laboratory of Molecular BasedMaterials, College of Chemistry and Material Science, AnhuiNormal University,Wuhu 241000, ChinaFax: +86-553-3869303E-mail: jiao421@mail.ahnu.edu.cn

[b] Hefei National Laboratory for Physical Sciences at Microscale,University of Science and Technology of China,Anhui 230026, ChinaSupporting information for this article is available on theWWW under http://dx.doi.org/10.1002/ejoc.201100736 or fromthe author.

© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Eur. J. Org. Chem. 2011, 5460–54685460

mylation enables the syntheses of a variety of α- and β-sub-stituted BODIPY dyes. The installation of formyl groups af-fects the electronic properties of the BODIPY chromophore,resulting in red- and blueshifts of the absorption and emis-sion maxima, respectively, for the α- and β-formylatedBODIPYs 3 and 5.

efficient synthesis of a series of β-formylated BODIPYs,[19]

which constitute a good platform for further functionaliza-tion of the BODIPY core at the β-position.[20] However,all of these β-functionalization methods face regioselectivityissues on the BODIPY core, such as the methyl groups in1,3,5,7-tetramethyl-substituted BODYPYs, because the re-giochemistry is predetermined by pyrrole-substitutedBODIPYs A and B (Figure 1), which block the other posi-tions from participating in these reactions.

Figure 1. IUPAC numbering system for the BODIPY core, chemi-cal structures for 1,3,5,7-tetramethyl-substituted BODIPYs A andB, and their β-formylated products C and D.[20]

Author's personal copy

A simple mixed-solvothermal route for LaPO4 nanorods: Synthesis,characterization, affecting factors and PL properties of LaPO4:Ce3+

Kai Mi a, Yonghong Ni a,⇑, Yanwei Xu a, Xiang Ma b, Jianming Hong b

aCollege of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, PR ChinabCenters of Modern Analyses, Nanjing University, Nanjing 210093, PR China

a r t i c l e i n f o

Article history:Received 27 October 2010Accepted 24 January 2011Available online 31 January 2011

Keywords:LaPO4 nanorodsMixed solvothermal synthesisScanning electron microscopyOptical property

a b s t r a c t

In this paper, LaPO4 nanorods have been successfully synthesized via a simple water–ethyleneglycol(H2O–EG) mixed-solvothermal route, employing lanthanum nitrate (La(NO3)3�xH2O) as a La3+ ion sourceand monobasic sodium phosphate (NaH2PO4�2H2O) as a PO3�

4 ion source. The as-obtained products werecharacterized by means of X-ray powder diffraction (XRD), energy dispersive spectrometry (EDS), (highresolution) transmission electron microscopy (HR/TEM), selected area electron diffraction (SAED) andfield emission scanning electron microscopy (FESEM). Some factors influencing the formation of LaPO4

nanorods, including the reaction temperature, the volume ratio of water/EG and the original amountof H2PO

�4 ions, were investigated. Experiments showed that the volume ratio of water/EG and the original

amount of H2PO�4 ions could markedly affect the morphology of the final product.

� 2011 Elsevier Inc. All rights reserved.

1. Introduction

Morphology-controllable synthesis of inorganic nanocrystals isone of the most important challenges in materials science becauseof the unique shape-dependent materials properties, which wouldresult in a wide range of electrical, optical, or magnetic propertiesand open a new domain of theoretical and technological interest[1]. In recent decade, much attention has been paid to variousone-dimensional (1D) nanostructures such as nanowires, nano-rods, nanotubes and nanobelts, owing to their unique structuralnature and physicochemical properties, as well as significantly po-tential applications in fabricating the next generation of nanoscaleelectronic, optoelectronic, and sensing devices [2–6]. As one ofimportant optical materials, luminescence materials have almostbecome a section of our daily life due to their uses in various fields,such as lighting, cathode ray tubes (CRTs), triphosphor fluorescentpowders, and flat panel display devices [7,8]. Rare earth ions aregood candidates as the luminescent center due to their special 4fintrashell transitions [9–13]; particularly, their orthophosphateshave been extensively used in the production of the luminescentor laser materials and photon upconversion materials [9].

Lanthanum phosphate (LaPO4) and its solid solutions have beenproven to be appropriate hosts as a highly efficient emitter of greenlight [14–16], due to its high melting temperature, chemical stabil-ity, and high light yields of the doped materials. Many methods

have been developed for the synthesis of LaPO4 or doped LaPO4,including combustion route [17], sonochemistry approach[18,19], electrospinning method [20], mechanical milling [21,22],precipitation [23] and coprecipitation [24], etc. For instance, Galliniet al. [17] reported a combustion method to produce LaPO4 and Sr-substituted LaPO4 nanoparticles. Brown et al. [18] and Yu et al. [19]respectively synthesized LaPO4 nanoparticles via employing thesonochemical route and studied their photoluminescent proper-ties. LaPO4 nanowires were obtained by Song group via an electros-pinning method [20]. In 2007, Diaz-Guillén and coworkersemployed a mechanical milling route to prepare LaPO4�nH2O nano-particles [21]; recently, this method was expanded for the synthe-sis of Sr-doped LaPO4 nanoparticles by Colomer et al. [22].Moreover, LaPO4 and Sr-doped LaPO4 nanoparticles were also pre-pared by controlled precipitation and coprecipitation methods[23,24]. However, more works focused on the preparation of rareearth doped LaPO4 nanostructures, especially Eu-doped LaPO4

nanostructures [25–30].As a green route, the hydrothermal or solvothermal technology

has been extensively used in the synthesis of micro-/nano-materi-als. For instance, Sun et al. employed a microemulsion assistedsolvothermal route for the synthesis of EuPO4 and LaPO4:Eu nano-rods; and investigated the influences of different surfactants on themorphology and size of EuPO4 [31]. In the current work, we designa simple water–ethyleneglycol (H2O–EG) mixed-solvothermalroute for synthesis of rod-like LaPO4 nanostructures via employingLa(NO3)3 as La3+ ion source and NaH2PO4 as PO3�

4 ion source. Thereaction is carried out at 130 �C for 10 h. Some factors influencingthe formation of LaPO4 nanorods, including the reaction tempera-

0021-9797/$ - see front matter � 2011 Elsevier Inc. All rights reserved.doi:10.1016/j.jcis.2011.01.076

⇑ Corresponding author. Fax: +86 553 3869303.E-mail address: niyh@mail.ahnu.edu.cn (Y. Ni).

Journal of Colloid and Interface Science 356 (2011) 490–495

Contents lists available at ScienceDirect

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11062 Chem. Commun., 2011, 47, 11062–11064 This journal is c The Royal Society of Chemistry 2011

Cite this: Chem. Commun., 2011, 47, 11062–11064

High adsorptive c-AlOOH(boehmite)@SiO2/Fe3O4 porous magneticmicrospheres for detection of toxic metal ions in drinking waterw

Yan Wei,abc Ran Yang,ac Yong-Xing Zhang,a Lun Wang,*b Jin-Huai Liu*a andXing-Jiu Huang*a

Received 13th July 2011, Accepted 24th August 2011

DOI: 10.1039/c1cc14215a

c-AlOOH(boehmite)@SiO2/Fe3O4 porous magnetic microspheres

with high adsorption capacity toward heavy metal ions were found

to be useful for the simultaneous and selective electrochemical

detection of five metal ions, such as ultratrace zinc(II), cadmium(II),

lead(II), copper(II), and mercury(II), in drinking water.

The most undesirable constituents (e.g. heavy metal ions) of

drinking water are capable of having a direct adverse impact

on human health and the environment.1–3 They can accumulate

in the kidneys and have a long biological half-life in humans of

10–35 years.4 Detecting a number of metal ions at very low

concentrations directly in the field is one of the key targets of

environmental chemists, and many papers have been dedicated

to this field.5–8 However, in recent research papers on electro-

chemical sensors, a larger and larger part is dedicated to the

detection of individual metal ions, typical examples can easily

be found in the literature,9–11 there are only a few reports on

the simultaneous and selective electrochemical detection using

nanoparticles with hierarchical nanostructures,12–16 partly

because of the difficulty in finding a suitable hierarchical unit

having a overall deposition potential allowing the simultaneous

measurement of several elements. Furthermore, only a few

examples of metal oxide nanomaterials for detection of heavy

metal ions have been reported. Therefore, it is of great

significance to develop electrochemical sensors based on metal

oxide nanomaterials for simultaneous and selective detection

of several metal ions in low concentrations.

In considering the high surface areas of the hierarchical nano-

architectures, it has been recognized that the strong adsorption

ability might provide new opportunities for improving

their sensing performance in practical applications. Our group

recently synthesized fried egg jellyfish-like g-AlOOH(boehmite)@

SiO2/Fe3O4 porous magnetic microspheres using a simple

template-induced method. The synthesized material was found

to have ultra high adsorption capacity toward aqueous Pb(II).

The maximum adsorption capacity, qm = 214.59 mg g�1, is

approximately 11.7-fold and 34.6-fold higher than the cases of

SiO2/Fe3O4 and Fe3O4 magnetic microspheres, respectively.17

Inspired by this surprising value, we wish to modify the

glassy carbon electrode (GCE) using g-AlOOH@SiO2/Fe3O4

porous magnetic microspheres for ultratrace metal ions analysis

by square wave anodic stripping voltammetry (SWASV) in

drinking water. We would expect that g-AlOOH@SiO2/Fe3O4

porous magnetic microspheres could act as a simultaneous and

selective probe for ultratrace target metal ions with high

sensitivity and selectivity.

The fabricated g-AlOOH@SiO2/Fe3O4 modified GCE was

firstly electrochemically characterized using electrochemical

impedance spectra (EIS) and cyclic voltammograms (Fig. 1).

Generally, the impedance spectra include a semicircle portion

and a linear portion. The semicircle diameter at higher fre-

quencies corresponds to the electron transfer resistance (Ret),

and the linear part at lower frequencies corresponds to the

diffusion process.18 As seen in Fig. 1a, it was observed that the

Ret of the Fe3O4 modified electrode was about 1.168 kO.Subsequently, when Fe3O4 microspheres were surrounded by

a SiO2 shell the Ret increased again to about 1.882 kO. After

the electrode was modified with g-AlOOH@SiO2/Fe3O4, the

Ret increased significantly to about 4.979 kO (see Fig. S1 for

surface morphology and Fig. S2 (ESIw) for fitting result of

EIS). This is due to the unique hierarchical structure of

AlOOH with many mesopores in the shell. Such a structure

Fig. 1 Nyquist diagram of electrochemical impedance spectra (a)

and cyclic voltammograms (b) of a bare GCE, Fe3O4, SiO2/Fe3O4,

and g-AlOOH(boehmite)@SiO2/Fe3O4 modified GCE in the solution

of 2 mM Fe(CN)63�/4� and 0.1 M KCl. In panel (b), the scan rate is

100 mV s�1.

a Institute of Intelligent Machines, Chinese Academy of Sciences,Hefei, 230031, PR China. E-mail: xingjiuhuang@iim.ac.cn,jhliu@iim.ac.cn; Fax: +86 551 5592420; Tel: +86 551 5591142

bCollege of Chemistry and Materials Science, Anhui NormalUniversity, Wuhu, 241000, PR China.E-mail: wanglun@mail.ahnu.edu.cn

cDepartment of Chemistry, Wannan Medical College, Wuhu, 241002,PR Chinaw Electronic supplementary information (ESI) available: Descriptionof experiments; optimum experimental conditions; SEM and TEM;fitted Nyquist plot; selectivity. See DOI: 10.1039/c1cc14215a

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Au−Pd Alloy and Core−Shell Nanostructures: One-Pot CoreductionPreparation, Formation Mechanism, and Electrochemical PropertiesLong Kuai, Xue Yu, Shaozhen Wang, Yan Sang, and Baoyou Geng*

College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Laboratory ofMolecular-Based Materials, Anhui Normal University, Wuhu 241000, P. R. China

*S Supporting Information

ABSTRACT: It is a known fact that Pd-based bimetallicnanostructures possess unique properties and excellentcatalytic performance. In this work, the Au−Pd alloy andcore−shell nanostructures have been prepared by a simpleone-pot hydrothermal coreduction route, and their formationprocess and mechanism are discussed in detail. A reducingcapacity-induced controlled reducing mechanism is proposedfor the formation process of Au−Pd bimetallic nanostructures.CTAB plays a key role in the formation of alloy Au−Pdnanostructures. When CTAB is absent, the products are typical core−shell nanostructures. Moreover, the as-preparednanostructures exhibit excellent electrocatalytic ORR performance in alkaline media, especially for Au−Pd alloy nanostructures.The overpotential of oxygen reduction gets reduced significantly, and the peak potential is positive-shifted by 44 and 34 mV incomparison with the core−shell ones and Pd/C catalyst, respectively. Thus, the controllable preparation and excellentelectrocatalytic properties will make them become a potentially cheaper Pd-based cathodic electrocatalyst for DAFCs in alkalinemedia.

1. INTRODUCTIONIn recent decades, noble metal nanostructures have receivedgreat attention for their unique properties and catalyticperformance.1 The extensive research of Pt is a case in pointdue to its exceptional electrocatalytic performance in the directalcohol fuel cells (DAFCs).1b−e However, the high cost and lowcontent in the Earth have limited its practical applications. It isdesirable to investigate new low-cost electrocatalysts with highperformance to replace the role of Pt. Recently, Pd-basednanostructures have been of great research interest for theirhigh catalytic performance.2 Besides, Pd is at least 50 timesmore abundant than Pt in the Earth. As a result, developing Pd-based electrocatalysts is an effective approach to drive thepractical applications of DAFCs.Extensive research indicates that Pd-based bimetallic

nanostructures exhibit unique properties, enhanced catalyticperformance, and electrocatalytic activity, which display someadvantages over that of Pt.3 Especially, the Au−Pd bimetallicsystem, including core−shell,4 alloy,5 etc., has drawn wideattention in the field of surface-enhanced Raman scattering(SERS),6 organic catalysis,6a,7 DAFCs electrocatalysis,8 and soforth. For example, Wang and co-workers prepared variousAu@Pd core−shell nanostructures by crystal epitaxial growthtechnology.9 They exhibit superior catalytic performance inSuzuki coupling reaction. In addition, Han et al. reportedoctapodal Au−Pd bimetallic nanoparticles, which have highercatalytic activity for the electro-oxidation of ethanol.10 Hence, itis desirable to fabricate Au−Pd bimetallic nanostructures forthe electrocatalysis of DAFCs. However, the preparation is still

a challenge although the Au−Pd nanostructures have attractedintensive research interests. Typically, the Au−Pd core−shellnanostructures are always obtained by two-step epitaxial growthapproach. As a result, the large-scale preparation is limited, andthe preparation process is always costly and time-consuming.Besides, the polycrystalline Au−Pd alloy nanostructures basedon self-assembling are rarely obtained although this structure isvery beneficial to catalysis.11 Thus, it is necessary to furtherdevelop the facile one-pot method to prepare Au−Pd bimetallicnanostructures with excellent properties.In this work, we successfully fabricate Au−Pd core−shell and

polycrystalline alloy bimetallic nanostructures through a facileone-pot hydrothermal coreduction route. HAuCl4 and H2PdCl4are herein used as the raw materials. Polyvinylpyrrolidone(PVP) is used as the reductant12 for the preparation of Au−Pdcore−shell nanostructures. Moreover, with the addition ofcetyltrimethylammonium bromide (CTAB), polycrystallinealloy Au−Pd nanostructures are prepared. The electrochemicalproperties of the as-prepared two kinds of Au−Pd bimetallicnanostructures are investigated by catalyzing the oxygenreduction reaction (ORR) in alkaline media, and it turns outthat the both bimetallic nanostructures exhibit good catalyticORR activity. Notably, polycrystalline Au−Pd alloy nanostruc-tures possess superior catalytic performance to Au−Pd core−shell nanostructures. The peak potential of O2 reduction is

Received: February 25, 2012Revised: April 13, 2012Published: April 13, 2012

Article

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© 2012 American Chemical Society 7168 dx.doi.org/10.1021/la300813z | Langmuir 2012, 28, 7168−7173

Electrochemical amplified detection of Hg2+ based on the supersandwich DNAstructure†

Guangfeng Wang,*a Xiuping He,a Baojuan Wang,b Xiaojun Zhanga and Lun Wang*a

Received 11th January 2012, Accepted 23rd February 2012

DOI: 10.1039/c2an35048c

A supersandwich DNA structure was fabricated and used for the

amplified detection of Hg2+.

In the current research age, DNA has emerged out of its biological

role and is being used more and more as an intelligent construction

material.1 Taking advantage of DNA’s remarkable molecular

recognition properties and structural features, DNA nanotech-

nology, in which long, single-stranded DNA (ssDNA) molecules are

folded into predetermined shapes, can be used to organize nano-

materials and self-assembled nanostructures in a programmable

way.2 As an essential aspect of bioanalysis, amplification has been

successfully achieved by employing enzymes, nanoparticles, or

nanocontainers as amplifiers for sensitive detection of biorecognition

events.3 To date, numerous amplified detection techniques based on

DNA have been developed including polymerase chain reaction

(PCR), rolling circle amplification (RCA) and someDNAmachines.4

It is well known that, although the PCR and RCA methods can be

used for amplification and detection, some inherent issues still cannot

be avoided, for example, complex operations, costly optical labels,

and dedicated instrumentation.5

Mercury ion (Hg2+) is a highly toxic heavy metal ion and is the

most stable form of inorganic mercury.6 The environmental and

health problems caused by Hg2+ have prompted researchers to

develop efficientmethods for selective and sensitive assay of themetal

ion to understand its distribution and pollution potential.7 Since Ono

et al. reported that mercury(II) ion possessed a unique property to

bind specifically to two DNA thymine bases (T) and could form

stable thymine–Hg2+–thymine (T–Hg2+–T) base pairs,8 various

sensors based on this property have been developed in recent

years.9–13 Among them, electrochemical methods have received

particular attention.13 However, most of these electrochemical

methods rely on the direct signal of Hg2+ or the mediator without

amplification or with amplification based on enzymes or

nanoparticles.

Our interest in Hg2+-sensing issues is how to amplify the electro-

chemical detection signal with a simple method. Stemming from the

amplified signal of a supersandwich DNA assay,14,15 based on our

recent work,16 here we report an electrochemical sensor for Hg2+

based on T–Hg2+–T with a supersandwich DNA structure. The

results demonstrated that the developed supersandwich DNA

amplified electrochemical Hg2+ sensor was highly sensitive and

selective for Hg2+ detection.

Scheme 1 depicts the fabrication of the supersandwich and tradi-

tional DNA assay based on T–Hg2+–T. In a traditional sandwich

structure, a single DNA sequence (S4) hybridizes with a single signal

probe S3 in the presence of Hg2+ with only one signal molecule.While

in a supersandwich structure, with T–Hg2+–T, in one unit a single

signal probe (S3) hybridizes to complementary regions on each of two

auxiliary DNA molecules (S2). With this hybridization, long con-

catemers containing multiple signal probes were created, which

further amplified the electrochemical signal. The electrochemical

impedance spectrum (EIS) of the assembling process is shown in the

ESI, Fig. S1†.

Fig. 1 is the CV response of the supersandwich and traditional

sandwich. In the absence of Hg2+, no redox peak was observed on the

S1 modified electrode. After the S1 modified electrode was incubated

with Hg2+, S2 and S3, with five T–Hg2+–T in every unit, the

Scheme 1 The fabrication of supersandwich and traditional sandwich

DNA structure with T–Hg2+–T.

aKey Laboratory of Chem–Biosensing, Key Laboratory of FunctionalMolecular Solids, College of Chemistry and Materials Science, AnhuiNormal University, Wuhu 241000, Anhui province, P R China. E-mail:wanglun@mail.ahnu.edu.cn; wangyuz@mail.ahnu.edu.cn; Fax: +86-553-3869303; Tel: +86-553-3869303bCollege of Life Science, Anhui Normal University, Wuhu 241000, P RChina

† Electronic supplementary information (ESI) available: Experimentaldetails, DNA sequence, control experiment optimization ofexperimental conditions. See DOI: 10.1039/c2an35048c

This journal is ª The Royal Society of Chemistry 2012 Analyst

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