2004481 (1 of 8) copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

CommuniCation

Encapsulating Copper Nanocrystals into MetalndashOrganic Frameworks for Cascade Reactions by Photothermal Catalysis

Lin Wang Shu-Rong Li Yu-Zhen Chen and Hai-Long Jiang

L Wang S-R Li Prof Y-Z ChenCollege of Chemistry and Chemical EngineeringQingdao UniversityQingdao Shandong 266071 P R ChinaE-mail chenzhen1738163comProf H-L JiangHefei National Laboratory for Physical Sciences at the MicroscaleDepartment of ChemistryUniversity of Science and Technology of ChinaHefei Anhui 230026 P R ChinaE-mail jianglabustceducn

The ORCID identification number(s) for the author(s) of this article can be found under httpsdoiorg101002smll202004481

DOI 101002smll202004481

Aromatic imines are important chemical intermediates in industrial fields for production of various fine chemicals[1ndash3] Generally a two-step tandem process coupling reduction of nitroarenes with reductive amination of ketones or alde-hydes to afford imines is highly attractive[4ndash7] In the first step of nitroarene reduction commercial PdC PtTiO2 or other supported metal catalysts are generally effective[3ndash5] However in most cases base additives high temperatures and high H2 pressures are usually required[2] In the second step cou-pling reaction of aromatic amines with carbonyl compounds usually require acid catalysts[8] Over the last decade several bifunctional noble-metal based catalysts (eg metalndashacid) have been reported for these cascade reactions but they are expensive and low-selective[910] The imine intermediates

Composite materials with multifunctional properties usually possess synergetic effects in catalysis toward cascade reactions In this work a facile strategy to the encapsulation of octahedral Cu2O nanocrystals (NCs) by metalndashorganic frameworks (MOFs) is reported and an oriented growth of MOF enclosures (namely HKUST-1) around Cu2O NCs with desired feedstock ratio is achieved The strategy defines the parameter range that precisely controls the etching rate of metal oxide and the MOF crystallization rate Finally the CuHKUST-1 composites with uniform morphology and controlled MOF thickness have been successfully fabricated after the reduction of Cu2O to Cu NCs in HKUST-1 The integration of Cu NCs properties with MOF advantages helps to create a multifunctional catalyst which exhibits cooperative catalytic activity and improved recyclability toward the one-pot cascade reactions under mild conditions involving visible-light irradiation The superior performance can be attributed to the plasmonic photothermal effect of Cu NCs while HKUST-1 shell provides Lewis acid sites substrates and H2 enrichment and stabilizes the Cu cores

are readily over-reduced to produce sec-ondary arylamines using hydrogen as a reductant and tedious separation proce-dure make it very challenging to obtain pure imines[910] Some substituted reduct-ants such as CH3OH CO or ammonia borane (NH3BH3) instead of H2 can be able to restrain further hydrogenation of imines[36] In general the exploration of economical effective and highly chem-oselective multifunctional solid catalysts for this one-pot cascade reactions is very desirable

Given the endothermic nature of nitroarene hydrogenation extra heat can be simply replaced with solar energy to promote the reaction by taking advantage of the surface plasmonic effect of some metal nanocrystals (NCs) such as Au Pd or Cu NCs[11ndash14] On the other hand metalndashorganic frameworks (MOFs)[15ndash19] possessing flexible structural designs

varied pore environments and modular assembly have shown widespread applications ranging from gas separation to catal-ysis and energy conversion[19ndash33] Particularly MOFs have been intensively reported as heterogeneous catalysts driven by the Lewis acid center based on coordinatively unsaturated metal sites[2334ndash36] More recently MOF composites involving metal nanoparticles are emerging as a new class of multifunc-tional materials with attractive optical properties catalysis and gas adsorption[37ndash43] Although the synthesis and catalysis of metal nanoparticle-MOF composites has been widely reported recently the rational assembly of metal NCs and MOFs with well-defined structure remains to be a largely underexplored area[44ndash55]

So far several types of metal NCs-MOF composite mate-rials have been reported 1) granular MOF particles accumu-late around a single metal crystal this is detrimental to facile diffusion of substrates and light harvest of plasmonic NCs due to thick MOF enclosures[44] 2) multiple metal NCs stay together inside a MOF particle in which the metal NCs are readily glomerate[4147ndash49] 3) directed growth of MOF on metal NCs in a one-to-one structure this is an optimal assembly though relatively few reports which have been reported mainly on large noble-metal NCs[51] and irregular morphologies[5055] Moreover the employed complex ALD technique[46] extra ionic surfactant[45] or particular synthetic conditions (eg under N2 in a glovebox)[48] make it difficult to extend these methods to different NCs Therefore a facile synthetic route to related com-posites is highly desirable

Small 2021 17 2004481

2004481 (2 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

In this work a simplified strategy has been developed to oriented growth of a typical MOF HKUST-1 on Cu2O NCs (referred as Cu2OHKUST-1) with directional control The route involves in situ etching of Cu2O and simultaneous assembly of copper ions with linkers to construct Cu-based MOF as the outer layer affording core-shell Cu2OHKUST-1 (Figure 1) One tricky point is to reach a careful balance between the kinetics of Cu2O etching and coordinative growth of MOF shell The as-synthesized Cu2OHKUST-1 is then reduced in situ during NH3BH3 hydrolysis to obtain the final CuHKUST-1 composite with well-retained morphology This multifunctional catalyst exhibits cooperatively promoted activity and high selectivity toward the cascade reactions under mild conditions involving visible-light irradiation in which Cu NCs offer photothermal effect and hydrogenation activity and the MOF shell affords Lewis acid sites and concentrates substrates Furthermore the protective MOF shell in CuHKUST-1 guarantees its better recyclability than that of CuHKUST-1 in which the MOF particles loaded on Cu NCs easily fall off during reaction

Our strategy involves etching coordination and reduction process to create CuHKUST-1 composite in which copper NCs are tightly wrapped by MOF enclosures Firstly the Cu2O octahedra with uniform sizes of asymp500 nm were hydrothermally synthesized and confirmed by scanning electron microscopy (SEM) images (Figure 2a and Figure S1a Supporting Informa-tion) The chosen MOF is a microporous Cu(II)-based HKUST-1 (alternatively known as Cu3(BTC)2) with a molecular formula [Cu3(C9H3O6)2(H2O)3]n and consists of dimeric cupric tetracar-boxylate units[56] Upon heating the HKUST-1 under vacuum at 373 K physically and chemically bound water molecules are removed from each metal Thus coordinatively unsaturated Cu(II) sites of the Cu2-paddle-wheel are responsible for Lewis acid centers In a typical synthesis of Cu2OHKUST-1 com-posite the naked Cu2O surface was gradually etched by reacting with the BTC ligand to form Cu-MOF shell The desired feed-stock ratio and assembly time are essential to the successful assembly of composites[57] and other reaction parameters such as solvent and temperature also have important influence on optimizing HKUST-1 synthesis

Herein two different structures have been fabricated The HKUST-1 particles are randomly deposited outside Cu2O NCs (referred as Cu2OHKUST-1) with traditional method by introducing as-synthesized Cu2O NCs into a DMSO solution containing 135-H3BTC under the same synthetic conditions of HKUST-1 The other structure is the directional growth of MOF framework on Cu2O NCs (denoted Cu2OHKUST-1) with meliorative reaction conditions (such as solvent tempera-ture) Figure 2b reveals that the HKUST-1 particles (asymp190 nm) partially cover the external surface of Cu2O NCs in Cu2OHKUST-1 This result indicates the general synthetic procedure would not be appropriate for this composite Considering this the reaction solvent and temperature are adjusted to match the appropriate Cu2O etching and coordination rate and thus control the crystallization direction of HKUST-1 affording an optimal assembly of Cu2OHKUST-1 As shown in Figure 2c each Cu2O NC is enclosed inside a thin HKUST-1 shell (asymp220 nm) with regular octahedron shape after 25 h However when the reaction time is extended to 35 h the thickness and morphology of HKUST-1 shell become uncontrollable as more Cu2O NCs are etched The SEM images clearly record the sig-nificant morphology change of Cu2OHKUST-1 from uni-form octahedron to irregular morphology which highlights the importance of optimizing the assembly time length (Figure 2d) X-ray photoelectron spectroscopy (XPS) characterization of Cu2O Cu2OHKUST-1 and Cu2OHKUST-1 have been investigated (Figure S2 Supporting Information) The XPS results show a clear 2p32 peak of Cu(I) emerging at 9318 eV for Cu2O a clear 2p32 peak of Cu(II) emerging at 9348 eV for Cu2OHKUST-1 and two clear 2p32 peaks emerging at 9318 and 9348 eV for Cu2OHKUST-1 Given the surface characteris-tics of XPS and the detection depth is generally less than 10 nm (lt220 nm) the XPS results could further prove their different structures of Cu2OHKUST-1 and Cu2OHKUST-1 The induc-tively coupled plasma atomic emission spectrometry (ICP-AES) analysis has confirmed that the actual contents of Cu2O in both samples are very close (Table S1 Supporting Information)

The as-synthesized Cu2OHKUST-1 and Cu2OHKUST-1 precursors can be in situ reduced by NH3BH3 during its hydro-lytic dehydrogenation to afford the final composite catalysts

Figure 1 Schematic illustration for the oriented growth of Cu2OHKUST-1 and random growth of Cu2OHKUST-1 composites

Small 2021 17 2004481

2004481 (3 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

CuHKUST-1 and CuHKUST-1 respectively SEM images show their well-preserved morphologies and sizes for both catalysts after reduction (Figure S1bc Supporting Informa-tion) Transmission electron microscopy (TEM) images further demonstrate their detailed microstructures random loading of MOF particles (asymp190 nm) on Cu for CuHKUST-1 (Figure 2e and Figure S3a Supporting Information) and uniform growth of MOF shell (asymp220 nm) on Cu for CuHKUST-1 (Figure 2fg and Figure S3b Supporting Information) Chemical compo-sitions and crystal structures of CuHKUST-1 are further confirmed by powder X-ray diffraction (PXRD) The good crys-tallinity of MOF and identifiable metallic Cu diffraction peaks

verify their successful formation and the complete reduction of Cu2OHKUST-1 to give CuHKUST-1 (Figure 2h)

The reaction process of Cu2O dissolution and HKUST-1 growth can be visually monitored through the temporal evolu-tion of the solution color at different assembly stages (Figure S4 Supporting Information) The corresponding PXRD clearly shows the gradually increasing MOF signals with a subsequent decrease in the peak intensities of Cu2O NCs as the Cu2O sur-face etching proceeds (Figure 2i) After etching for 5 h the Cu2O is completely dissolved and transferred to HKUST-1 The corresponding TEM image reflects the irregular octahedron of HKUST-1 particles (Figure S5 Supporting Information)

Figure 2 SEM images for a) Cu2O NCs b) Cu2OHKUST-1 c) Cu2OHKUST-1-25 h and d) Cu2OHKUST-1-35 h TEM images for e) CuHKUST-1 fg) CuHKUST-1-25 h h) Powder X-ray diffraction (PXRD) patterns of simulated HKUST-1 Cu2O and Cu and as-synthesized HKUST-1 Cu2O NCs Cu NCs Cu2OHKUST-1 and CuHKUST-1 i) PXRD patterns of Cu2OHKUST-1 under different etching time lengths

Small 2021 17 2004481

2004481 (4 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

Meanwhile cubic Cu2O nanocrystals are also selected as precur-sors and sacrificial templates to fabricate c-CuHKUST-1 using the same synthetic method of CuHKUST-1 The HKUST-1 has also been successfully grown on cubic Cu NCs with well-maintained sizes and morphologies proving the universality of this synthetic route (Figure S6 Supporting Information)

The N2 adsorptiondesorption curves have been meas-ured at 77 K (Figure S7 Supporting Information) The BET (BrunauerndashEmmettndashTeller) surface areas for HKUST-1 Cu2OHKUST-1 and CuHKUST-1 are 14523 3650 and 3650 m2 gndash1 respectively The noticeably decreased surface areas of Cu2OHKUST-1 and CuHKUST-1 are primarily ascribed to the mass occupation by Cu2O and Cu NCs sup-porting their successful assembly with the MOF framework with retained structure integrity[3841] As-synthesized Cu2O NCs show a broad absorption band at 200ndash800 nm under visible-light irradiation indicating its surface plasmonic

resonance (SPR) property which has been well inherited to the Cu2OHKUST-1 composite (Figure 3a)

One-pot cascade reaction involving hydrogenation of nitrobenzene by NH3BH3 followed by reductive amination of benzaldehyde has been investigated to evaluate the catalytic performance of CuHKUST-1 During in situ reduction of Cu2OHKUST-1 with NH3BH3 catalytic NH3BH3 hydrolysis and hydrogenation of nitrobenzene take place simultaneously and the formed CuHKUST-1 behaves as the efficient catalyst for the reactions Figure 3b shows the volume of hydrogen gen-erated at different reaction time lengths in presence of different catalysts Notably the curves are divided into three sections the initial slow stage (0ndash05 min) for the induction process to ini-tiate the reaction the subsequent fast stage (05ndash10 min) for the reduction process of Cu2O to Cu NCs and the final stage (after 1 min) for the catalytic process by Cu NCs Obviously the Cu2O NCs and Cu2OHKUST-1 have almost the same catalytic

Figure 3 Synthesis of aromatic imines through hydrogenation of nitrobenzene and reductive amination of benzaldehyde a) UVVis absorption spectra for HKUST-1 Cu2O NCs and Cu2OHKUST-1 b) Plots of time versus the volume of hydrogen generated from catalytic hydrolysis of NH3BH3 over Cu2OHKUST-1 Cu2OHKUST-1 and Cu2O NCs c) Conversion of the cascade reactions under different experimental conditions d) Recyclability test at reaction 10 h through five consecutive runs using CuHKUST-1 and CuHKUST-1 Reaction conditions 02 mmol nitrobenzene 02 mmol benzal-dehyde 15 mg NH3BH3 50 mg catalyst 15 mL ethanol visible-light irradiation (100 mW cmminus2)

Small 2021 17 2004481

2004481 (5 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

activities which indicate that the MOF coating has no influence on the diffusion of NH3BH3 to access active sites The slightly lower activity of CuHKUST-1 is likely due to some aggregation of Cu NCs For cascade reactions the Cu2OHKUST-1 exhibits decent catalytic activity and completes the conversion with 100 selectivity toward N-benzylideneaniline over 10 h under mild conditions involving visible-light irradiation (100 mW cmminus2) which even exceeds most of noble-metal catalysts (Figure 3c)[910] The over-reduction of imines can be effectively suppressed probably due to the inactive Cu NCs in the hydrogenation of unsaturated CN and moderate reductivity of NH3BH3[940] When the light illumination was replaced by external heating with unchanged reaction temperature and other conditions (Table S2 Supporting Information) Cu2OHKUST-1 com-pleted the reactions after 14 h While it takes 17 h to complete the reactions in the dark at room temperature unambiguously reflecting the importance of light irradiation For comparison the cascade reactions have been investigated in the absence of catalyst or presence of Cu2OHKUST-1 Cu2O NCs Cu NCs HKUST-1 under similar conditions (Table S3 Supporting Infor-mation) The CuHKUST-1 exhibits lower activity and takes 12 h to complete the reactions (Entry 2 Table S3 Supporting Infor-mation) which may be due to the poor synergistic effect when some MOF particles are separated from Cu NCs during the reaction (Figure S8 Supporting Information) To exclude the influence of HKUST-1 morphology the second coupling reac-tion of phenylamine with benzaldehyde catalyzed by Cu2OHKUST-1 and Cu2OHKUST-1 has been investigated Both cata-lysts have almost the same catalytic activities and complete the reaction within 5 h indicating the same degree of unsaturated

Cu nodes for both samples (Figure S9 Supporting Informa-tion) The Cu2O NCs and Cu NCs can only catalyze the first step to give phenylamine intermediate due to the lack of Lewis acid sites (Entries 34 Table S3 Supporting Information) To directly demonstrate the Lewis acid property of HKUST-1 the second coupling reaction of phenylamine with benzaldehyde and other two typical acid catalyzed reactions cyanosilylation of benzalde-hyde and ring opening of epoxy butane have been investigated The good catalytic activity of HKUST-1 for these reactions fur-ther confirms the existing unsaturated Cu nodes in HKUST-1 (Figure S10 Supporting Information) These results demon-strate the significant influence of HKUST-1 on the catalytic performance In addition no reaction product can be detected using HKUST-1 only or without catalyst (Entries 56 Table S3 Supporting Information) To verify the heterogeneous catalytic property of CuHKUST-1 a hot filtration test is carried out for the mixture after 6 h of reaction no imine is produced even after 6 h of the reaction indicating that the reaction process is truly heterogeneous (Figure S11 Supporting Information) In addition no Cu element is detected for the solution after the reaction by the ICP analysis demonstrating the absence of Cu leaching (Table S1 Supporting Information) All the catalytic data above indicate that in the composite structure both Cu NCs and MOF shell are indispensable for excellent catalytic per-formance toward the cascade reactions

HKUST-1 has been reported to be unstable under acetoni-trile solvent in the previous work[58] To verify the feasibility of HKUST-1 in our reaction system the HKUST-1 is immersed in the reaction solvent of ethanol for 24 h The well-remained patterns of HKUST-1 after immersion indicate the good stability

Figure 4 ab) TEM images and cd) PXRD patterns of ac) CuHKUST-1 and bd) CuHKUST-1 after 5 catalytic cycles

Small 2021 17 2004481

2004481 (6 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

of HKUST-1 in ethanol In addition the Cu2OHKUST-1 cata-lyst is also immersed in a concentrated solution of NH3BH3 for 24 h no changed PXRD patterns of Cu2OHKUST-1 demon-strate the feasibility of Cu2OHKUST-1 in the reaction system (Figure S12 Supporting Information) For industrial applica-tions long-term recyclability of catalysts is an important factor While the catalytic activity of CuHKUST-1 and CuHKUST-1 is very similar there is a sharp contrast between their subse-quent recycling activities (Figure 3d and Figure S13 Supporting Information) Satisfactorily the CuHKUST-1 catalyst is able to maintain its catalytic activity and selectivity even after five consecutive cycles whereas the CuHKUST-1 catalyst presents evident activity drop from 98 to 40 during the five runs The recycling results can be well explained by TEM observations (Figure 4ab) that the size and regular morphology of CuHKUST-1 are well preserved while the HKUST-1 particles suffer from moving and are prone to separate from Cu NCs causing the deteriorated recycling performance of CuHKUST-1 The BET surface areas for Cu2OHKUST-1 before and after five runs are 3665 and 1949 m2 gndash1 respectively The noticeably decreased surface areas are probably ascribed to the falling off of MOF particles during catalytic cycles (Figure S7 Supporting Information) The changed color of CuHKUST-1 catalyst after five runs perfectly supports the above conjecture (Figure S8 Supporting Information) In addition the PXRD patterns for both catalysts before and after recycle experiments suggest their well retained crystallinity (Figure 4cd) These results further demonstrate the advantages of precise surface engineering and the unique assembly structure of CuHKUST-1

In summary the core-shell structured CuHKUST-1 composite has been rationally fabricated using a straightforward dissolutioncoordination approach The key factors for this successful oriented growth of MOF on Cu2O NCs with regular morphologies lie in the desired feedstock ratio and suitable assembly time length The resultant CuHKUST-1 effectively combines plasmonic photothermal effects and hydrogena-tion activity of Cu NCs and the Lewis acidity of the MOF to achieve synergetic catalysis for one-pot cascade reactions Furthermore thanks to the protection effect of HKUST-1 shell the crystallinity morphology and nanostructure of the composite as well as catalytic activity are well maintained even after five cycles This work for the first time attempts to integrate the SPR effects of metal nanocrystals and Lewis acidity of MOFs by their proper assembly to realize synergisti-cally enhanced catalytic performance for one-pot cascade reac-tions It is believed the extension of this synthetic strategy to other metalMOF composites for synergistically enhanced applications

Experimental SectionPreparation of Octahedron-Cu2O NCs The synthesis of octahedron-

Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution (100 mL 001 m) and 5 g of polyvinylpyrrolidone were added into a round bottom flask and vigorously stirred for 30 min at 55 degC Then 10 mL of 2 m NaOH solution was added dropwise into the round-bottomed flask The transparent bluish solution gradually turned turbid blue and then changed to black The temperature was kept constant for 30 min A

10 mL ascorbic acid solution (06 m) was added dropwise to the flask and allowed to react at a constant temperature (55 degC) for 3 h after which the solution became orange The mixture was centrifuged at 11 000 rpm to obtain an orange precipitation which was washed adequately with ultra-pure water and anhydrous ethanol The resulting product was dried further at room temperature under dynamic vacuum for 12 h

Preparation of Cube-Cu2O NCs The synthesis of cube-Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution in a 250 mL round-bottomed flask was placed in an oil bath at 55 degC and stirred for 30 min Then 10 mL of 2 m NaOH solution was added dropwise to the flask The transparent bluish solution gradually turned into turbid blue and then turbid black The temperature was kept constant for 30 min The 10 mL ascorbic acid solution (06 m) was pushed dropwise into the round-bottomed flask the reaction at a constant temperature for 5 h after which the solution became orange The mixed solution was collected by centrifugation at 11 000 rpm to obtain orange precipitation then washed repeatedly with ultra-pure water and anhydrous ethanol The resulting product was dried under vacuum for 12 h at room temperature

Preparation of HKUST-1 HKUST-1 was synthesized according to the previous report with modifications[60] Typically a mixture of Cu (NO3)23H2O (122 g 524 mmol) and 135-benzenetricarboxylate (058 g) were dissolved in 5 g of dimethyl sulfoxide (DMSO) to obtain the precursor solution of which 200 microL was added to 10 mL of methanol and stirred for 10 min at room temperature to obtain a blue solution This solution was centrifuged at a speed of 11 000 rpm to obtain a blue precipitation then washed repeatedly with methanol The resulting product was dried at 60 degC for 12 h under vacuum

Preparation of Cu2OHKUST-1 Typically Cu2O NC (05 mmol 00715 g) and 135-H3BTC (067 mmol 01407 g) were sonicated in 5 g of DMSO to obtain the precursor solution of which 200 microL was added into 10 mL methanol and stirred for 10 min at room temperature to obtain a dark green solution The mixture was centrifuged at 11 000 rpm to obtain a dark green precipitation then washed repeatedly with methanol and recentrifuged The resulting product was placed in a vacuum oven and dried at 60 degC for 12 h

Preparation of Cu2OHKUST-1 Typically Cu2O NCs (05 mmol 00715 g) was dissolved in 40 mL benzyl alcohol and sonicated until Cu2O NCs were highly dispersed (recorded as solution A) A solution of 135-H3BTC (067 mmol 01407 g) and ethanol was sonicated to form solution B which was put into an oil bath at 60 degC and stirred for 5 min at 60 degC Solution B was dropwise added into the solution A and continuously stirred for 25 h The product was centrifuged washed with anhydrous ethanol for 3 times then dried at 50 degC to obtain a dark green powder

Catalytic Performance Evaluation for Hydrolysis Reaction of Ammonia Borane In general Cu2OHKUST-1 (50 mg) or Cu2OHKUST-1 (50 mg) or Cu2O NCs (25 mg) catalyst together with 15 mL water were added into a round-bottomed flask under magnetic stirring The reaction started when 15 mg of NH3BH3 was placed in the mixture The volume of the evolved hydrogen gas was monitored by recording the displacement of water in the gas burette The reaction was stopped when no gas was generated

Catalytic Performance of Cu2OHKUST-1 for the Cascade Reactions Typically a mixture of 02 mmol nitrobenzene and 50 mg of Cu2OHKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL ethanol The reaction was carried out under light irradiation from a 300 W Xe lamp followed by addition of NH3BH3 (15 mg) and 02 mmol benzaldehyde to the flask For comparison 50 mg of Cu2O NCs Cu NCs HKUST-1 catalyst or no addition was used to catalyze the reaction and all other reaction conditions were kept the same To verify the importance of the light irradiation in the control experiments visible-light irradiation was replaced by external heating or under dark at room temperature with other conditions unchanged The catalytic yield was tracked and identified by gas chromatography For the recycling experiments the catalyst was separated by centrifugation and washed

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (3 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

CuHKUST-1 and CuHKUST-1 respectively SEM images show their well-preserved morphologies and sizes for both catalysts after reduction (Figure S1bc Supporting Informa-tion) Transmission electron microscopy (TEM) images further demonstrate their detailed microstructures random loading of MOF particles (asymp190 nm) on Cu for CuHKUST-1 (Figure 2e and Figure S3a Supporting Information) and uniform growth of MOF shell (asymp220 nm) on Cu for CuHKUST-1 (Figure 2fg and Figure S3b Supporting Information) Chemical compo-sitions and crystal structures of CuHKUST-1 are further confirmed by powder X-ray diffraction (PXRD) The good crys-tallinity of MOF and identifiable metallic Cu diffraction peaks

verify their successful formation and the complete reduction of Cu2OHKUST-1 to give CuHKUST-1 (Figure 2h)

The reaction process of Cu2O dissolution and HKUST-1 growth can be visually monitored through the temporal evolu-tion of the solution color at different assembly stages (Figure S4 Supporting Information) The corresponding PXRD clearly shows the gradually increasing MOF signals with a subsequent decrease in the peak intensities of Cu2O NCs as the Cu2O sur-face etching proceeds (Figure 2i) After etching for 5 h the Cu2O is completely dissolved and transferred to HKUST-1 The corresponding TEM image reflects the irregular octahedron of HKUST-1 particles (Figure S5 Supporting Information)

Figure 2 SEM images for a) Cu2O NCs b) Cu2OHKUST-1 c) Cu2OHKUST-1-25 h and d) Cu2OHKUST-1-35 h TEM images for e) CuHKUST-1 fg) CuHKUST-1-25 h h) Powder X-ray diffraction (PXRD) patterns of simulated HKUST-1 Cu2O and Cu and as-synthesized HKUST-1 Cu2O NCs Cu NCs Cu2OHKUST-1 and CuHKUST-1 i) PXRD patterns of Cu2OHKUST-1 under different etching time lengths

Small 2021 17 2004481

2004481 (4 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

Meanwhile cubic Cu2O nanocrystals are also selected as precur-sors and sacrificial templates to fabricate c-CuHKUST-1 using the same synthetic method of CuHKUST-1 The HKUST-1 has also been successfully grown on cubic Cu NCs with well-maintained sizes and morphologies proving the universality of this synthetic route (Figure S6 Supporting Information)

The N2 adsorptiondesorption curves have been meas-ured at 77 K (Figure S7 Supporting Information) The BET (BrunauerndashEmmettndashTeller) surface areas for HKUST-1 Cu2OHKUST-1 and CuHKUST-1 are 14523 3650 and 3650 m2 gndash1 respectively The noticeably decreased surface areas of Cu2OHKUST-1 and CuHKUST-1 are primarily ascribed to the mass occupation by Cu2O and Cu NCs sup-porting their successful assembly with the MOF framework with retained structure integrity[3841] As-synthesized Cu2O NCs show a broad absorption band at 200ndash800 nm under visible-light irradiation indicating its surface plasmonic

resonance (SPR) property which has been well inherited to the Cu2OHKUST-1 composite (Figure 3a)

One-pot cascade reaction involving hydrogenation of nitrobenzene by NH3BH3 followed by reductive amination of benzaldehyde has been investigated to evaluate the catalytic performance of CuHKUST-1 During in situ reduction of Cu2OHKUST-1 with NH3BH3 catalytic NH3BH3 hydrolysis and hydrogenation of nitrobenzene take place simultaneously and the formed CuHKUST-1 behaves as the efficient catalyst for the reactions Figure 3b shows the volume of hydrogen gen-erated at different reaction time lengths in presence of different catalysts Notably the curves are divided into three sections the initial slow stage (0ndash05 min) for the induction process to ini-tiate the reaction the subsequent fast stage (05ndash10 min) for the reduction process of Cu2O to Cu NCs and the final stage (after 1 min) for the catalytic process by Cu NCs Obviously the Cu2O NCs and Cu2OHKUST-1 have almost the same catalytic

Figure 3 Synthesis of aromatic imines through hydrogenation of nitrobenzene and reductive amination of benzaldehyde a) UVVis absorption spectra for HKUST-1 Cu2O NCs and Cu2OHKUST-1 b) Plots of time versus the volume of hydrogen generated from catalytic hydrolysis of NH3BH3 over Cu2OHKUST-1 Cu2OHKUST-1 and Cu2O NCs c) Conversion of the cascade reactions under different experimental conditions d) Recyclability test at reaction 10 h through five consecutive runs using CuHKUST-1 and CuHKUST-1 Reaction conditions 02 mmol nitrobenzene 02 mmol benzal-dehyde 15 mg NH3BH3 50 mg catalyst 15 mL ethanol visible-light irradiation (100 mW cmminus2)

Small 2021 17 2004481

2004481 (5 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

activities which indicate that the MOF coating has no influence on the diffusion of NH3BH3 to access active sites The slightly lower activity of CuHKUST-1 is likely due to some aggregation of Cu NCs For cascade reactions the Cu2OHKUST-1 exhibits decent catalytic activity and completes the conversion with 100 selectivity toward N-benzylideneaniline over 10 h under mild conditions involving visible-light irradiation (100 mW cmminus2) which even exceeds most of noble-metal catalysts (Figure 3c)[910] The over-reduction of imines can be effectively suppressed probably due to the inactive Cu NCs in the hydrogenation of unsaturated CN and moderate reductivity of NH3BH3[940] When the light illumination was replaced by external heating with unchanged reaction temperature and other conditions (Table S2 Supporting Information) Cu2OHKUST-1 com-pleted the reactions after 14 h While it takes 17 h to complete the reactions in the dark at room temperature unambiguously reflecting the importance of light irradiation For comparison the cascade reactions have been investigated in the absence of catalyst or presence of Cu2OHKUST-1 Cu2O NCs Cu NCs HKUST-1 under similar conditions (Table S3 Supporting Infor-mation) The CuHKUST-1 exhibits lower activity and takes 12 h to complete the reactions (Entry 2 Table S3 Supporting Infor-mation) which may be due to the poor synergistic effect when some MOF particles are separated from Cu NCs during the reaction (Figure S8 Supporting Information) To exclude the influence of HKUST-1 morphology the second coupling reac-tion of phenylamine with benzaldehyde catalyzed by Cu2OHKUST-1 and Cu2OHKUST-1 has been investigated Both cata-lysts have almost the same catalytic activities and complete the reaction within 5 h indicating the same degree of unsaturated

Cu nodes for both samples (Figure S9 Supporting Informa-tion) The Cu2O NCs and Cu NCs can only catalyze the first step to give phenylamine intermediate due to the lack of Lewis acid sites (Entries 34 Table S3 Supporting Information) To directly demonstrate the Lewis acid property of HKUST-1 the second coupling reaction of phenylamine with benzaldehyde and other two typical acid catalyzed reactions cyanosilylation of benzalde-hyde and ring opening of epoxy butane have been investigated The good catalytic activity of HKUST-1 for these reactions fur-ther confirms the existing unsaturated Cu nodes in HKUST-1 (Figure S10 Supporting Information) These results demon-strate the significant influence of HKUST-1 on the catalytic performance In addition no reaction product can be detected using HKUST-1 only or without catalyst (Entries 56 Table S3 Supporting Information) To verify the heterogeneous catalytic property of CuHKUST-1 a hot filtration test is carried out for the mixture after 6 h of reaction no imine is produced even after 6 h of the reaction indicating that the reaction process is truly heterogeneous (Figure S11 Supporting Information) In addition no Cu element is detected for the solution after the reaction by the ICP analysis demonstrating the absence of Cu leaching (Table S1 Supporting Information) All the catalytic data above indicate that in the composite structure both Cu NCs and MOF shell are indispensable for excellent catalytic per-formance toward the cascade reactions

HKUST-1 has been reported to be unstable under acetoni-trile solvent in the previous work[58] To verify the feasibility of HKUST-1 in our reaction system the HKUST-1 is immersed in the reaction solvent of ethanol for 24 h The well-remained patterns of HKUST-1 after immersion indicate the good stability

Figure 4 ab) TEM images and cd) PXRD patterns of ac) CuHKUST-1 and bd) CuHKUST-1 after 5 catalytic cycles

Small 2021 17 2004481

2004481 (6 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

of HKUST-1 in ethanol In addition the Cu2OHKUST-1 cata-lyst is also immersed in a concentrated solution of NH3BH3 for 24 h no changed PXRD patterns of Cu2OHKUST-1 demon-strate the feasibility of Cu2OHKUST-1 in the reaction system (Figure S12 Supporting Information) For industrial applica-tions long-term recyclability of catalysts is an important factor While the catalytic activity of CuHKUST-1 and CuHKUST-1 is very similar there is a sharp contrast between their subse-quent recycling activities (Figure 3d and Figure S13 Supporting Information) Satisfactorily the CuHKUST-1 catalyst is able to maintain its catalytic activity and selectivity even after five consecutive cycles whereas the CuHKUST-1 catalyst presents evident activity drop from 98 to 40 during the five runs The recycling results can be well explained by TEM observations (Figure 4ab) that the size and regular morphology of CuHKUST-1 are well preserved while the HKUST-1 particles suffer from moving and are prone to separate from Cu NCs causing the deteriorated recycling performance of CuHKUST-1 The BET surface areas for Cu2OHKUST-1 before and after five runs are 3665 and 1949 m2 gndash1 respectively The noticeably decreased surface areas are probably ascribed to the falling off of MOF particles during catalytic cycles (Figure S7 Supporting Information) The changed color of CuHKUST-1 catalyst after five runs perfectly supports the above conjecture (Figure S8 Supporting Information) In addition the PXRD patterns for both catalysts before and after recycle experiments suggest their well retained crystallinity (Figure 4cd) These results further demonstrate the advantages of precise surface engineering and the unique assembly structure of CuHKUST-1

In summary the core-shell structured CuHKUST-1 composite has been rationally fabricated using a straightforward dissolutioncoordination approach The key factors for this successful oriented growth of MOF on Cu2O NCs with regular morphologies lie in the desired feedstock ratio and suitable assembly time length The resultant CuHKUST-1 effectively combines plasmonic photothermal effects and hydrogena-tion activity of Cu NCs and the Lewis acidity of the MOF to achieve synergetic catalysis for one-pot cascade reactions Furthermore thanks to the protection effect of HKUST-1 shell the crystallinity morphology and nanostructure of the composite as well as catalytic activity are well maintained even after five cycles This work for the first time attempts to integrate the SPR effects of metal nanocrystals and Lewis acidity of MOFs by their proper assembly to realize synergisti-cally enhanced catalytic performance for one-pot cascade reac-tions It is believed the extension of this synthetic strategy to other metalMOF composites for synergistically enhanced applications

Experimental SectionPreparation of Octahedron-Cu2O NCs The synthesis of octahedron-

Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution (100 mL 001 m) and 5 g of polyvinylpyrrolidone were added into a round bottom flask and vigorously stirred for 30 min at 55 degC Then 10 mL of 2 m NaOH solution was added dropwise into the round-bottomed flask The transparent bluish solution gradually turned turbid blue and then changed to black The temperature was kept constant for 30 min A

10 mL ascorbic acid solution (06 m) was added dropwise to the flask and allowed to react at a constant temperature (55 degC) for 3 h after which the solution became orange The mixture was centrifuged at 11 000 rpm to obtain an orange precipitation which was washed adequately with ultra-pure water and anhydrous ethanol The resulting product was dried further at room temperature under dynamic vacuum for 12 h

Preparation of Cube-Cu2O NCs The synthesis of cube-Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution in a 250 mL round-bottomed flask was placed in an oil bath at 55 degC and stirred for 30 min Then 10 mL of 2 m NaOH solution was added dropwise to the flask The transparent bluish solution gradually turned into turbid blue and then turbid black The temperature was kept constant for 30 min The 10 mL ascorbic acid solution (06 m) was pushed dropwise into the round-bottomed flask the reaction at a constant temperature for 5 h after which the solution became orange The mixed solution was collected by centrifugation at 11 000 rpm to obtain orange precipitation then washed repeatedly with ultra-pure water and anhydrous ethanol The resulting product was dried under vacuum for 12 h at room temperature

Preparation of HKUST-1 HKUST-1 was synthesized according to the previous report with modifications[60] Typically a mixture of Cu (NO3)23H2O (122 g 524 mmol) and 135-benzenetricarboxylate (058 g) were dissolved in 5 g of dimethyl sulfoxide (DMSO) to obtain the precursor solution of which 200 microL was added to 10 mL of methanol and stirred for 10 min at room temperature to obtain a blue solution This solution was centrifuged at a speed of 11 000 rpm to obtain a blue precipitation then washed repeatedly with methanol The resulting product was dried at 60 degC for 12 h under vacuum

Preparation of Cu2OHKUST-1 Typically Cu2O NC (05 mmol 00715 g) and 135-H3BTC (067 mmol 01407 g) were sonicated in 5 g of DMSO to obtain the precursor solution of which 200 microL was added into 10 mL methanol and stirred for 10 min at room temperature to obtain a dark green solution The mixture was centrifuged at 11 000 rpm to obtain a dark green precipitation then washed repeatedly with methanol and recentrifuged The resulting product was placed in a vacuum oven and dried at 60 degC for 12 h

Preparation of Cu2OHKUST-1 Typically Cu2O NCs (05 mmol 00715 g) was dissolved in 40 mL benzyl alcohol and sonicated until Cu2O NCs were highly dispersed (recorded as solution A) A solution of 135-H3BTC (067 mmol 01407 g) and ethanol was sonicated to form solution B which was put into an oil bath at 60 degC and stirred for 5 min at 60 degC Solution B was dropwise added into the solution A and continuously stirred for 25 h The product was centrifuged washed with anhydrous ethanol for 3 times then dried at 50 degC to obtain a dark green powder

Catalytic Performance Evaluation for Hydrolysis Reaction of Ammonia Borane In general Cu2OHKUST-1 (50 mg) or Cu2OHKUST-1 (50 mg) or Cu2O NCs (25 mg) catalyst together with 15 mL water were added into a round-bottomed flask under magnetic stirring The reaction started when 15 mg of NH3BH3 was placed in the mixture The volume of the evolved hydrogen gas was monitored by recording the displacement of water in the gas burette The reaction was stopped when no gas was generated

Catalytic Performance of Cu2OHKUST-1 for the Cascade Reactions Typically a mixture of 02 mmol nitrobenzene and 50 mg of Cu2OHKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL ethanol The reaction was carried out under light irradiation from a 300 W Xe lamp followed by addition of NH3BH3 (15 mg) and 02 mmol benzaldehyde to the flask For comparison 50 mg of Cu2O NCs Cu NCs HKUST-1 catalyst or no addition was used to catalyze the reaction and all other reaction conditions were kept the same To verify the importance of the light irradiation in the control experiments visible-light irradiation was replaced by external heating or under dark at room temperature with other conditions unchanged The catalytic yield was tracked and identified by gas chromatography For the recycling experiments the catalyst was separated by centrifugation and washed

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (4 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

Meanwhile cubic Cu2O nanocrystals are also selected as precur-sors and sacrificial templates to fabricate c-CuHKUST-1 using the same synthetic method of CuHKUST-1 The HKUST-1 has also been successfully grown on cubic Cu NCs with well-maintained sizes and morphologies proving the universality of this synthetic route (Figure S6 Supporting Information)

The N2 adsorptiondesorption curves have been meas-ured at 77 K (Figure S7 Supporting Information) The BET (BrunauerndashEmmettndashTeller) surface areas for HKUST-1 Cu2OHKUST-1 and CuHKUST-1 are 14523 3650 and 3650 m2 gndash1 respectively The noticeably decreased surface areas of Cu2OHKUST-1 and CuHKUST-1 are primarily ascribed to the mass occupation by Cu2O and Cu NCs sup-porting their successful assembly with the MOF framework with retained structure integrity[3841] As-synthesized Cu2O NCs show a broad absorption band at 200ndash800 nm under visible-light irradiation indicating its surface plasmonic

resonance (SPR) property which has been well inherited to the Cu2OHKUST-1 composite (Figure 3a)

One-pot cascade reaction involving hydrogenation of nitrobenzene by NH3BH3 followed by reductive amination of benzaldehyde has been investigated to evaluate the catalytic performance of CuHKUST-1 During in situ reduction of Cu2OHKUST-1 with NH3BH3 catalytic NH3BH3 hydrolysis and hydrogenation of nitrobenzene take place simultaneously and the formed CuHKUST-1 behaves as the efficient catalyst for the reactions Figure 3b shows the volume of hydrogen gen-erated at different reaction time lengths in presence of different catalysts Notably the curves are divided into three sections the initial slow stage (0ndash05 min) for the induction process to ini-tiate the reaction the subsequent fast stage (05ndash10 min) for the reduction process of Cu2O to Cu NCs and the final stage (after 1 min) for the catalytic process by Cu NCs Obviously the Cu2O NCs and Cu2OHKUST-1 have almost the same catalytic

Figure 3 Synthesis of aromatic imines through hydrogenation of nitrobenzene and reductive amination of benzaldehyde a) UVVis absorption spectra for HKUST-1 Cu2O NCs and Cu2OHKUST-1 b) Plots of time versus the volume of hydrogen generated from catalytic hydrolysis of NH3BH3 over Cu2OHKUST-1 Cu2OHKUST-1 and Cu2O NCs c) Conversion of the cascade reactions under different experimental conditions d) Recyclability test at reaction 10 h through five consecutive runs using CuHKUST-1 and CuHKUST-1 Reaction conditions 02 mmol nitrobenzene 02 mmol benzal-dehyde 15 mg NH3BH3 50 mg catalyst 15 mL ethanol visible-light irradiation (100 mW cmminus2)

Small 2021 17 2004481

2004481 (5 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

activities which indicate that the MOF coating has no influence on the diffusion of NH3BH3 to access active sites The slightly lower activity of CuHKUST-1 is likely due to some aggregation of Cu NCs For cascade reactions the Cu2OHKUST-1 exhibits decent catalytic activity and completes the conversion with 100 selectivity toward N-benzylideneaniline over 10 h under mild conditions involving visible-light irradiation (100 mW cmminus2) which even exceeds most of noble-metal catalysts (Figure 3c)[910] The over-reduction of imines can be effectively suppressed probably due to the inactive Cu NCs in the hydrogenation of unsaturated CN and moderate reductivity of NH3BH3[940] When the light illumination was replaced by external heating with unchanged reaction temperature and other conditions (Table S2 Supporting Information) Cu2OHKUST-1 com-pleted the reactions after 14 h While it takes 17 h to complete the reactions in the dark at room temperature unambiguously reflecting the importance of light irradiation For comparison the cascade reactions have been investigated in the absence of catalyst or presence of Cu2OHKUST-1 Cu2O NCs Cu NCs HKUST-1 under similar conditions (Table S3 Supporting Infor-mation) The CuHKUST-1 exhibits lower activity and takes 12 h to complete the reactions (Entry 2 Table S3 Supporting Infor-mation) which may be due to the poor synergistic effect when some MOF particles are separated from Cu NCs during the reaction (Figure S8 Supporting Information) To exclude the influence of HKUST-1 morphology the second coupling reac-tion of phenylamine with benzaldehyde catalyzed by Cu2OHKUST-1 and Cu2OHKUST-1 has been investigated Both cata-lysts have almost the same catalytic activities and complete the reaction within 5 h indicating the same degree of unsaturated

Cu nodes for both samples (Figure S9 Supporting Informa-tion) The Cu2O NCs and Cu NCs can only catalyze the first step to give phenylamine intermediate due to the lack of Lewis acid sites (Entries 34 Table S3 Supporting Information) To directly demonstrate the Lewis acid property of HKUST-1 the second coupling reaction of phenylamine with benzaldehyde and other two typical acid catalyzed reactions cyanosilylation of benzalde-hyde and ring opening of epoxy butane have been investigated The good catalytic activity of HKUST-1 for these reactions fur-ther confirms the existing unsaturated Cu nodes in HKUST-1 (Figure S10 Supporting Information) These results demon-strate the significant influence of HKUST-1 on the catalytic performance In addition no reaction product can be detected using HKUST-1 only or without catalyst (Entries 56 Table S3 Supporting Information) To verify the heterogeneous catalytic property of CuHKUST-1 a hot filtration test is carried out for the mixture after 6 h of reaction no imine is produced even after 6 h of the reaction indicating that the reaction process is truly heterogeneous (Figure S11 Supporting Information) In addition no Cu element is detected for the solution after the reaction by the ICP analysis demonstrating the absence of Cu leaching (Table S1 Supporting Information) All the catalytic data above indicate that in the composite structure both Cu NCs and MOF shell are indispensable for excellent catalytic per-formance toward the cascade reactions

HKUST-1 has been reported to be unstable under acetoni-trile solvent in the previous work[58] To verify the feasibility of HKUST-1 in our reaction system the HKUST-1 is immersed in the reaction solvent of ethanol for 24 h The well-remained patterns of HKUST-1 after immersion indicate the good stability

Figure 4 ab) TEM images and cd) PXRD patterns of ac) CuHKUST-1 and bd) CuHKUST-1 after 5 catalytic cycles

Small 2021 17 2004481

2004481 (6 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

of HKUST-1 in ethanol In addition the Cu2OHKUST-1 cata-lyst is also immersed in a concentrated solution of NH3BH3 for 24 h no changed PXRD patterns of Cu2OHKUST-1 demon-strate the feasibility of Cu2OHKUST-1 in the reaction system (Figure S12 Supporting Information) For industrial applica-tions long-term recyclability of catalysts is an important factor While the catalytic activity of CuHKUST-1 and CuHKUST-1 is very similar there is a sharp contrast between their subse-quent recycling activities (Figure 3d and Figure S13 Supporting Information) Satisfactorily the CuHKUST-1 catalyst is able to maintain its catalytic activity and selectivity even after five consecutive cycles whereas the CuHKUST-1 catalyst presents evident activity drop from 98 to 40 during the five runs The recycling results can be well explained by TEM observations (Figure 4ab) that the size and regular morphology of CuHKUST-1 are well preserved while the HKUST-1 particles suffer from moving and are prone to separate from Cu NCs causing the deteriorated recycling performance of CuHKUST-1 The BET surface areas for Cu2OHKUST-1 before and after five runs are 3665 and 1949 m2 gndash1 respectively The noticeably decreased surface areas are probably ascribed to the falling off of MOF particles during catalytic cycles (Figure S7 Supporting Information) The changed color of CuHKUST-1 catalyst after five runs perfectly supports the above conjecture (Figure S8 Supporting Information) In addition the PXRD patterns for both catalysts before and after recycle experiments suggest their well retained crystallinity (Figure 4cd) These results further demonstrate the advantages of precise surface engineering and the unique assembly structure of CuHKUST-1

In summary the core-shell structured CuHKUST-1 composite has been rationally fabricated using a straightforward dissolutioncoordination approach The key factors for this successful oriented growth of MOF on Cu2O NCs with regular morphologies lie in the desired feedstock ratio and suitable assembly time length The resultant CuHKUST-1 effectively combines plasmonic photothermal effects and hydrogena-tion activity of Cu NCs and the Lewis acidity of the MOF to achieve synergetic catalysis for one-pot cascade reactions Furthermore thanks to the protection effect of HKUST-1 shell the crystallinity morphology and nanostructure of the composite as well as catalytic activity are well maintained even after five cycles This work for the first time attempts to integrate the SPR effects of metal nanocrystals and Lewis acidity of MOFs by their proper assembly to realize synergisti-cally enhanced catalytic performance for one-pot cascade reac-tions It is believed the extension of this synthetic strategy to other metalMOF composites for synergistically enhanced applications

Experimental SectionPreparation of Octahedron-Cu2O NCs The synthesis of octahedron-

Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution (100 mL 001 m) and 5 g of polyvinylpyrrolidone were added into a round bottom flask and vigorously stirred for 30 min at 55 degC Then 10 mL of 2 m NaOH solution was added dropwise into the round-bottomed flask The transparent bluish solution gradually turned turbid blue and then changed to black The temperature was kept constant for 30 min A

10 mL ascorbic acid solution (06 m) was added dropwise to the flask and allowed to react at a constant temperature (55 degC) for 3 h after which the solution became orange The mixture was centrifuged at 11 000 rpm to obtain an orange precipitation which was washed adequately with ultra-pure water and anhydrous ethanol The resulting product was dried further at room temperature under dynamic vacuum for 12 h

Preparation of Cube-Cu2O NCs The synthesis of cube-Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution in a 250 mL round-bottomed flask was placed in an oil bath at 55 degC and stirred for 30 min Then 10 mL of 2 m NaOH solution was added dropwise to the flask The transparent bluish solution gradually turned into turbid blue and then turbid black The temperature was kept constant for 30 min The 10 mL ascorbic acid solution (06 m) was pushed dropwise into the round-bottomed flask the reaction at a constant temperature for 5 h after which the solution became orange The mixed solution was collected by centrifugation at 11 000 rpm to obtain orange precipitation then washed repeatedly with ultra-pure water and anhydrous ethanol The resulting product was dried under vacuum for 12 h at room temperature

Preparation of HKUST-1 HKUST-1 was synthesized according to the previous report with modifications[60] Typically a mixture of Cu (NO3)23H2O (122 g 524 mmol) and 135-benzenetricarboxylate (058 g) were dissolved in 5 g of dimethyl sulfoxide (DMSO) to obtain the precursor solution of which 200 microL was added to 10 mL of methanol and stirred for 10 min at room temperature to obtain a blue solution This solution was centrifuged at a speed of 11 000 rpm to obtain a blue precipitation then washed repeatedly with methanol The resulting product was dried at 60 degC for 12 h under vacuum

Preparation of Cu2OHKUST-1 Typically Cu2O NC (05 mmol 00715 g) and 135-H3BTC (067 mmol 01407 g) were sonicated in 5 g of DMSO to obtain the precursor solution of which 200 microL was added into 10 mL methanol and stirred for 10 min at room temperature to obtain a dark green solution The mixture was centrifuged at 11 000 rpm to obtain a dark green precipitation then washed repeatedly with methanol and recentrifuged The resulting product was placed in a vacuum oven and dried at 60 degC for 12 h

Preparation of Cu2OHKUST-1 Typically Cu2O NCs (05 mmol 00715 g) was dissolved in 40 mL benzyl alcohol and sonicated until Cu2O NCs were highly dispersed (recorded as solution A) A solution of 135-H3BTC (067 mmol 01407 g) and ethanol was sonicated to form solution B which was put into an oil bath at 60 degC and stirred for 5 min at 60 degC Solution B was dropwise added into the solution A and continuously stirred for 25 h The product was centrifuged washed with anhydrous ethanol for 3 times then dried at 50 degC to obtain a dark green powder

Catalytic Performance Evaluation for Hydrolysis Reaction of Ammonia Borane In general Cu2OHKUST-1 (50 mg) or Cu2OHKUST-1 (50 mg) or Cu2O NCs (25 mg) catalyst together with 15 mL water were added into a round-bottomed flask under magnetic stirring The reaction started when 15 mg of NH3BH3 was placed in the mixture The volume of the evolved hydrogen gas was monitored by recording the displacement of water in the gas burette The reaction was stopped when no gas was generated

Catalytic Performance of Cu2OHKUST-1 for the Cascade Reactions Typically a mixture of 02 mmol nitrobenzene and 50 mg of Cu2OHKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL ethanol The reaction was carried out under light irradiation from a 300 W Xe lamp followed by addition of NH3BH3 (15 mg) and 02 mmol benzaldehyde to the flask For comparison 50 mg of Cu2O NCs Cu NCs HKUST-1 catalyst or no addition was used to catalyze the reaction and all other reaction conditions were kept the same To verify the importance of the light irradiation in the control experiments visible-light irradiation was replaced by external heating or under dark at room temperature with other conditions unchanged The catalytic yield was tracked and identified by gas chromatography For the recycling experiments the catalyst was separated by centrifugation and washed

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (5 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

activities which indicate that the MOF coating has no influence on the diffusion of NH3BH3 to access active sites The slightly lower activity of CuHKUST-1 is likely due to some aggregation of Cu NCs For cascade reactions the Cu2OHKUST-1 exhibits decent catalytic activity and completes the conversion with 100 selectivity toward N-benzylideneaniline over 10 h under mild conditions involving visible-light irradiation (100 mW cmminus2) which even exceeds most of noble-metal catalysts (Figure 3c)[910] The over-reduction of imines can be effectively suppressed probably due to the inactive Cu NCs in the hydrogenation of unsaturated CN and moderate reductivity of NH3BH3[940] When the light illumination was replaced by external heating with unchanged reaction temperature and other conditions (Table S2 Supporting Information) Cu2OHKUST-1 com-pleted the reactions after 14 h While it takes 17 h to complete the reactions in the dark at room temperature unambiguously reflecting the importance of light irradiation For comparison the cascade reactions have been investigated in the absence of catalyst or presence of Cu2OHKUST-1 Cu2O NCs Cu NCs HKUST-1 under similar conditions (Table S3 Supporting Infor-mation) The CuHKUST-1 exhibits lower activity and takes 12 h to complete the reactions (Entry 2 Table S3 Supporting Infor-mation) which may be due to the poor synergistic effect when some MOF particles are separated from Cu NCs during the reaction (Figure S8 Supporting Information) To exclude the influence of HKUST-1 morphology the second coupling reac-tion of phenylamine with benzaldehyde catalyzed by Cu2OHKUST-1 and Cu2OHKUST-1 has been investigated Both cata-lysts have almost the same catalytic activities and complete the reaction within 5 h indicating the same degree of unsaturated

Cu nodes for both samples (Figure S9 Supporting Informa-tion) The Cu2O NCs and Cu NCs can only catalyze the first step to give phenylamine intermediate due to the lack of Lewis acid sites (Entries 34 Table S3 Supporting Information) To directly demonstrate the Lewis acid property of HKUST-1 the second coupling reaction of phenylamine with benzaldehyde and other two typical acid catalyzed reactions cyanosilylation of benzalde-hyde and ring opening of epoxy butane have been investigated The good catalytic activity of HKUST-1 for these reactions fur-ther confirms the existing unsaturated Cu nodes in HKUST-1 (Figure S10 Supporting Information) These results demon-strate the significant influence of HKUST-1 on the catalytic performance In addition no reaction product can be detected using HKUST-1 only or without catalyst (Entries 56 Table S3 Supporting Information) To verify the heterogeneous catalytic property of CuHKUST-1 a hot filtration test is carried out for the mixture after 6 h of reaction no imine is produced even after 6 h of the reaction indicating that the reaction process is truly heterogeneous (Figure S11 Supporting Information) In addition no Cu element is detected for the solution after the reaction by the ICP analysis demonstrating the absence of Cu leaching (Table S1 Supporting Information) All the catalytic data above indicate that in the composite structure both Cu NCs and MOF shell are indispensable for excellent catalytic per-formance toward the cascade reactions

HKUST-1 has been reported to be unstable under acetoni-trile solvent in the previous work[58] To verify the feasibility of HKUST-1 in our reaction system the HKUST-1 is immersed in the reaction solvent of ethanol for 24 h The well-remained patterns of HKUST-1 after immersion indicate the good stability

Figure 4 ab) TEM images and cd) PXRD patterns of ac) CuHKUST-1 and bd) CuHKUST-1 after 5 catalytic cycles

Small 2021 17 2004481

2004481 (6 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

of HKUST-1 in ethanol In addition the Cu2OHKUST-1 cata-lyst is also immersed in a concentrated solution of NH3BH3 for 24 h no changed PXRD patterns of Cu2OHKUST-1 demon-strate the feasibility of Cu2OHKUST-1 in the reaction system (Figure S12 Supporting Information) For industrial applica-tions long-term recyclability of catalysts is an important factor While the catalytic activity of CuHKUST-1 and CuHKUST-1 is very similar there is a sharp contrast between their subse-quent recycling activities (Figure 3d and Figure S13 Supporting Information) Satisfactorily the CuHKUST-1 catalyst is able to maintain its catalytic activity and selectivity even after five consecutive cycles whereas the CuHKUST-1 catalyst presents evident activity drop from 98 to 40 during the five runs The recycling results can be well explained by TEM observations (Figure 4ab) that the size and regular morphology of CuHKUST-1 are well preserved while the HKUST-1 particles suffer from moving and are prone to separate from Cu NCs causing the deteriorated recycling performance of CuHKUST-1 The BET surface areas for Cu2OHKUST-1 before and after five runs are 3665 and 1949 m2 gndash1 respectively The noticeably decreased surface areas are probably ascribed to the falling off of MOF particles during catalytic cycles (Figure S7 Supporting Information) The changed color of CuHKUST-1 catalyst after five runs perfectly supports the above conjecture (Figure S8 Supporting Information) In addition the PXRD patterns for both catalysts before and after recycle experiments suggest their well retained crystallinity (Figure 4cd) These results further demonstrate the advantages of precise surface engineering and the unique assembly structure of CuHKUST-1

In summary the core-shell structured CuHKUST-1 composite has been rationally fabricated using a straightforward dissolutioncoordination approach The key factors for this successful oriented growth of MOF on Cu2O NCs with regular morphologies lie in the desired feedstock ratio and suitable assembly time length The resultant CuHKUST-1 effectively combines plasmonic photothermal effects and hydrogena-tion activity of Cu NCs and the Lewis acidity of the MOF to achieve synergetic catalysis for one-pot cascade reactions Furthermore thanks to the protection effect of HKUST-1 shell the crystallinity morphology and nanostructure of the composite as well as catalytic activity are well maintained even after five cycles This work for the first time attempts to integrate the SPR effects of metal nanocrystals and Lewis acidity of MOFs by their proper assembly to realize synergisti-cally enhanced catalytic performance for one-pot cascade reac-tions It is believed the extension of this synthetic strategy to other metalMOF composites for synergistically enhanced applications

Experimental SectionPreparation of Octahedron-Cu2O NCs The synthesis of octahedron-

Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution (100 mL 001 m) and 5 g of polyvinylpyrrolidone were added into a round bottom flask and vigorously stirred for 30 min at 55 degC Then 10 mL of 2 m NaOH solution was added dropwise into the round-bottomed flask The transparent bluish solution gradually turned turbid blue and then changed to black The temperature was kept constant for 30 min A

10 mL ascorbic acid solution (06 m) was added dropwise to the flask and allowed to react at a constant temperature (55 degC) for 3 h after which the solution became orange The mixture was centrifuged at 11 000 rpm to obtain an orange precipitation which was washed adequately with ultra-pure water and anhydrous ethanol The resulting product was dried further at room temperature under dynamic vacuum for 12 h

Preparation of Cube-Cu2O NCs The synthesis of cube-Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution in a 250 mL round-bottomed flask was placed in an oil bath at 55 degC and stirred for 30 min Then 10 mL of 2 m NaOH solution was added dropwise to the flask The transparent bluish solution gradually turned into turbid blue and then turbid black The temperature was kept constant for 30 min The 10 mL ascorbic acid solution (06 m) was pushed dropwise into the round-bottomed flask the reaction at a constant temperature for 5 h after which the solution became orange The mixed solution was collected by centrifugation at 11 000 rpm to obtain orange precipitation then washed repeatedly with ultra-pure water and anhydrous ethanol The resulting product was dried under vacuum for 12 h at room temperature

Preparation of HKUST-1 HKUST-1 was synthesized according to the previous report with modifications[60] Typically a mixture of Cu (NO3)23H2O (122 g 524 mmol) and 135-benzenetricarboxylate (058 g) were dissolved in 5 g of dimethyl sulfoxide (DMSO) to obtain the precursor solution of which 200 microL was added to 10 mL of methanol and stirred for 10 min at room temperature to obtain a blue solution This solution was centrifuged at a speed of 11 000 rpm to obtain a blue precipitation then washed repeatedly with methanol The resulting product was dried at 60 degC for 12 h under vacuum

Preparation of Cu2OHKUST-1 Typically Cu2O NC (05 mmol 00715 g) and 135-H3BTC (067 mmol 01407 g) were sonicated in 5 g of DMSO to obtain the precursor solution of which 200 microL was added into 10 mL methanol and stirred for 10 min at room temperature to obtain a dark green solution The mixture was centrifuged at 11 000 rpm to obtain a dark green precipitation then washed repeatedly with methanol and recentrifuged The resulting product was placed in a vacuum oven and dried at 60 degC for 12 h

Preparation of Cu2OHKUST-1 Typically Cu2O NCs (05 mmol 00715 g) was dissolved in 40 mL benzyl alcohol and sonicated until Cu2O NCs were highly dispersed (recorded as solution A) A solution of 135-H3BTC (067 mmol 01407 g) and ethanol was sonicated to form solution B which was put into an oil bath at 60 degC and stirred for 5 min at 60 degC Solution B was dropwise added into the solution A and continuously stirred for 25 h The product was centrifuged washed with anhydrous ethanol for 3 times then dried at 50 degC to obtain a dark green powder

Catalytic Performance Evaluation for Hydrolysis Reaction of Ammonia Borane In general Cu2OHKUST-1 (50 mg) or Cu2OHKUST-1 (50 mg) or Cu2O NCs (25 mg) catalyst together with 15 mL water were added into a round-bottomed flask under magnetic stirring The reaction started when 15 mg of NH3BH3 was placed in the mixture The volume of the evolved hydrogen gas was monitored by recording the displacement of water in the gas burette The reaction was stopped when no gas was generated

Catalytic Performance of Cu2OHKUST-1 for the Cascade Reactions Typically a mixture of 02 mmol nitrobenzene and 50 mg of Cu2OHKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL ethanol The reaction was carried out under light irradiation from a 300 W Xe lamp followed by addition of NH3BH3 (15 mg) and 02 mmol benzaldehyde to the flask For comparison 50 mg of Cu2O NCs Cu NCs HKUST-1 catalyst or no addition was used to catalyze the reaction and all other reaction conditions were kept the same To verify the importance of the light irradiation in the control experiments visible-light irradiation was replaced by external heating or under dark at room temperature with other conditions unchanged The catalytic yield was tracked and identified by gas chromatography For the recycling experiments the catalyst was separated by centrifugation and washed

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (6 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

of HKUST-1 in ethanol In addition the Cu2OHKUST-1 cata-lyst is also immersed in a concentrated solution of NH3BH3 for 24 h no changed PXRD patterns of Cu2OHKUST-1 demon-strate the feasibility of Cu2OHKUST-1 in the reaction system (Figure S12 Supporting Information) For industrial applica-tions long-term recyclability of catalysts is an important factor While the catalytic activity of CuHKUST-1 and CuHKUST-1 is very similar there is a sharp contrast between their subse-quent recycling activities (Figure 3d and Figure S13 Supporting Information) Satisfactorily the CuHKUST-1 catalyst is able to maintain its catalytic activity and selectivity even after five consecutive cycles whereas the CuHKUST-1 catalyst presents evident activity drop from 98 to 40 during the five runs The recycling results can be well explained by TEM observations (Figure 4ab) that the size and regular morphology of CuHKUST-1 are well preserved while the HKUST-1 particles suffer from moving and are prone to separate from Cu NCs causing the deteriorated recycling performance of CuHKUST-1 The BET surface areas for Cu2OHKUST-1 before and after five runs are 3665 and 1949 m2 gndash1 respectively The noticeably decreased surface areas are probably ascribed to the falling off of MOF particles during catalytic cycles (Figure S7 Supporting Information) The changed color of CuHKUST-1 catalyst after five runs perfectly supports the above conjecture (Figure S8 Supporting Information) In addition the PXRD patterns for both catalysts before and after recycle experiments suggest their well retained crystallinity (Figure 4cd) These results further demonstrate the advantages of precise surface engineering and the unique assembly structure of CuHKUST-1

In summary the core-shell structured CuHKUST-1 composite has been rationally fabricated using a straightforward dissolutioncoordination approach The key factors for this successful oriented growth of MOF on Cu2O NCs with regular morphologies lie in the desired feedstock ratio and suitable assembly time length The resultant CuHKUST-1 effectively combines plasmonic photothermal effects and hydrogena-tion activity of Cu NCs and the Lewis acidity of the MOF to achieve synergetic catalysis for one-pot cascade reactions Furthermore thanks to the protection effect of HKUST-1 shell the crystallinity morphology and nanostructure of the composite as well as catalytic activity are well maintained even after five cycles This work for the first time attempts to integrate the SPR effects of metal nanocrystals and Lewis acidity of MOFs by their proper assembly to realize synergisti-cally enhanced catalytic performance for one-pot cascade reac-tions It is believed the extension of this synthetic strategy to other metalMOF composites for synergistically enhanced applications

Experimental SectionPreparation of Octahedron-Cu2O NCs The synthesis of octahedron-

Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution (100 mL 001 m) and 5 g of polyvinylpyrrolidone were added into a round bottom flask and vigorously stirred for 30 min at 55 degC Then 10 mL of 2 m NaOH solution was added dropwise into the round-bottomed flask The transparent bluish solution gradually turned turbid blue and then changed to black The temperature was kept constant for 30 min A

10 mL ascorbic acid solution (06 m) was added dropwise to the flask and allowed to react at a constant temperature (55 degC) for 3 h after which the solution became orange The mixture was centrifuged at 11 000 rpm to obtain an orange precipitation which was washed adequately with ultra-pure water and anhydrous ethanol The resulting product was dried further at room temperature under dynamic vacuum for 12 h

Preparation of Cube-Cu2O NCs The synthesis of cube-Cu2O NCs was referred to the previous report with modifications[59] Typically a copper chloride solution in a 250 mL round-bottomed flask was placed in an oil bath at 55 degC and stirred for 30 min Then 10 mL of 2 m NaOH solution was added dropwise to the flask The transparent bluish solution gradually turned into turbid blue and then turbid black The temperature was kept constant for 30 min The 10 mL ascorbic acid solution (06 m) was pushed dropwise into the round-bottomed flask the reaction at a constant temperature for 5 h after which the solution became orange The mixed solution was collected by centrifugation at 11 000 rpm to obtain orange precipitation then washed repeatedly with ultra-pure water and anhydrous ethanol The resulting product was dried under vacuum for 12 h at room temperature

Preparation of HKUST-1 HKUST-1 was synthesized according to the previous report with modifications[60] Typically a mixture of Cu (NO3)23H2O (122 g 524 mmol) and 135-benzenetricarboxylate (058 g) were dissolved in 5 g of dimethyl sulfoxide (DMSO) to obtain the precursor solution of which 200 microL was added to 10 mL of methanol and stirred for 10 min at room temperature to obtain a blue solution This solution was centrifuged at a speed of 11 000 rpm to obtain a blue precipitation then washed repeatedly with methanol The resulting product was dried at 60 degC for 12 h under vacuum

Preparation of Cu2OHKUST-1 Typically Cu2O NC (05 mmol 00715 g) and 135-H3BTC (067 mmol 01407 g) were sonicated in 5 g of DMSO to obtain the precursor solution of which 200 microL was added into 10 mL methanol and stirred for 10 min at room temperature to obtain a dark green solution The mixture was centrifuged at 11 000 rpm to obtain a dark green precipitation then washed repeatedly with methanol and recentrifuged The resulting product was placed in a vacuum oven and dried at 60 degC for 12 h

Preparation of Cu2OHKUST-1 Typically Cu2O NCs (05 mmol 00715 g) was dissolved in 40 mL benzyl alcohol and sonicated until Cu2O NCs were highly dispersed (recorded as solution A) A solution of 135-H3BTC (067 mmol 01407 g) and ethanol was sonicated to form solution B which was put into an oil bath at 60 degC and stirred for 5 min at 60 degC Solution B was dropwise added into the solution A and continuously stirred for 25 h The product was centrifuged washed with anhydrous ethanol for 3 times then dried at 50 degC to obtain a dark green powder

Catalytic Performance Evaluation for Hydrolysis Reaction of Ammonia Borane In general Cu2OHKUST-1 (50 mg) or Cu2OHKUST-1 (50 mg) or Cu2O NCs (25 mg) catalyst together with 15 mL water were added into a round-bottomed flask under magnetic stirring The reaction started when 15 mg of NH3BH3 was placed in the mixture The volume of the evolved hydrogen gas was monitored by recording the displacement of water in the gas burette The reaction was stopped when no gas was generated

Catalytic Performance of Cu2OHKUST-1 for the Cascade Reactions Typically a mixture of 02 mmol nitrobenzene and 50 mg of Cu2OHKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL ethanol The reaction was carried out under light irradiation from a 300 W Xe lamp followed by addition of NH3BH3 (15 mg) and 02 mmol benzaldehyde to the flask For comparison 50 mg of Cu2O NCs Cu NCs HKUST-1 catalyst or no addition was used to catalyze the reaction and all other reaction conditions were kept the same To verify the importance of the light irradiation in the control experiments visible-light irradiation was replaced by external heating or under dark at room temperature with other conditions unchanged The catalytic yield was tracked and identified by gas chromatography For the recycling experiments the catalyst was separated by centrifugation and washed

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (7 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

with ethanol and was reused in the subsequent reaction under identical reaction conditions

Catalytic Performance of Cu2OHKUST-1 for the Cyanosilylation of Benzaldehyde Typically a mixture of 1 mmol benzaldehyde and 1 mmol trimethylcyanosilane were dispersed in a round-bottomed flask (25 mL) with 100 mg of HKUST-1 catalyst and 15 mL pentane The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Catalytic Performance of Cu2OHKUST-1 for the Ring Opening of Epoxy Butane In general a mixture of 1 mmol epoxy butane and 50 mg of HKUST-1 catalyst were dispersed in a round-bottomed flask (25 mL) with 15 mL methanol The reaction was carried out at 40 degC The catalytic yield was tracked and identified by gas chromatography

Supporting InformationSupporting Information is available from the Wiley Online Library or from the author

AcknowledgementsThe authors are grateful to the financial support by the National Natural Science Foundation of China (21701093 21725101 21673213 21871244 and 21521001) Key Research and Development Program of Shandong Province (2019GGX103043) and Chinese Postdoctoral Science Foundation (2018T110664 and 2017M622127)

Conflict of InterestThe authors declare no conflict of interest

Keywordscascade reaction metal nanocrystals metalndashorganic frameworks photothermal catalysis

Received July 25 2020Revised September 4 2020

Published online January 18 2021

[1] N Uematsu A Fujii S Hashiguchi T Ikariya R Noyori J Am Chem Soc 1996 118 4916

[2] E Byun B Hong K A D Castro M Lim H Rhee J Org Chem 2007 72 9815

[3] M Shi Y-M Xu Angew Chem Int Ed 2002 41 4507[4] J Huang L Yu L He Y-M Liu Y Cao K-N Fan Green Chem

2011 13 2672[5] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[6] Y Xiang Q Meng X Li J Wang Chem Commun 2010 46 5918[7] X Yang H Tao W R Leow J Li Y Tan Y Zhang T Zhang

X Chen S Gao R Cao J Catal 2019 373 116[8] M J Climent A Corma S Iborra Chem Rev 2011 111 1072[9] F G Cirujano A Leyva-Peacuterez A Corma F X Llabreacutes i Xamena

ChemCatChem 2013 5 538[10] Y-Z Chen Y-X Zhou H Wang J Lu T Uchida Q Xu S-H Yu

H-L Jiang ACS Catal 2015 5 2062[11] P K Jain X Huang I H El-Sayed M A El-Sayed Acc Chem Res

2008 41 1578

[12] F Wang C Li H Chen R Jiang L D Sun Q Li J Wang J C Yu C H Yan J Am Chem Soc 2013 135 5588

[13] S Linic U Aslam C Boerigter M Morabito Nat Mater 2015 14 567

[14] R Long K Mao X Ye W Yan Y Huang J Wang Y Fu X Wang X Wu Y Xie Y Xiong J Am Chem Soc 2013 135 3200

[15] H Furukawa K E Cordova M OrsquoKeeffe O M Yaghi Science 2013 341 1230444

[16] H-C Zhou S Kitagawa Chem Soc Rev 2014 43 5415[17] T Islamoglu S Goswami Z Li A J Howarth O K Farha

J T Hupp Acc Chem Res 2017 50 805[18] P-Q Liao N-Y Huang W-X Zhang J-P Zhang X-M Chen Sci-

ence 2017 356 1193[19] W-H Li W-H Deng G-E Wang G Xu EnergyChem 2020 2

100029[20] X Zhao Y Wang D-S Li X Bu P Feng Adv Mater 2018 30

1705189[21] C-C Hou H-F Wang C Li Q Xu Energy Environ Sci 2020 13

1658[22] D E Jaramillo D A Reed H Z H Jiang J Oktawiec

M W Mara A C Forse D J Lussier R A Murphy M Cunningham V Colombo D K Shuh J A Reimer J R Long Nat Mater 2020 19 517

[23] T Zhang W Lin Chem Soc Rev 2014 43 5982[24] J Lee C Y Chuah J Kim Y Kim N Ko Y Seo K Kim T H Bae

E Lee Angew Chem Int Ed 2018 57 7869[25] M Zhao K Yuan Y Wang G Li J Guo L Gu W Hu H Zhao

Z Tang Nature 2016 539 76[26] T Kundu M Wahiduzzaman B B Shah G Maurin D Zhao

Angew Chem Int Ed 2019 58 8073[27] X-L Lv S Yuan L-H Xie H F Darke Y Chen T He C Dong

B Wang Y-Z Zhang J-R Li H-C Zhou J Am Chem Soc 2019 141 10283

[28] M-H Yu B Space D Franz W Zhou C He L Li R Krishna Z Chang W Li T-L Hu X-H Bu J Am Chem Soc 2019 141 17703

[29] N Li J Liu J-J Liu L-Z Dong Z-F Xin Y-L Teng Y-Q Lan Angew Chem Int Ed 2019 58 5226

[30] C-C Cao C-X Chen Z-W Wei Q-F Qiu N-X Zhu Y-Y Xiong J-J Jiang D Wang C-Y Su J Am Chem Soc 2019 141 2589

[31] Y-B Huang J Liang X-S Wang R Cao Chem Soc Rev 2017 46 126

[32] K Shen L Zhang X Chen L Liu D Zhang Y Han J Chen J Long R Luque Y Li B Chen Science 2018 359 206

[33] J-D Xiao H-L Jiang Acc Chem Res 2019 52 356[34] X Deng Z Li H Garcia Chem - Eur J 2017 23 11189[35] S Horike M Dinca K Tamaki J R Long J Am Chem Soc 2008

130 5854[36] F Vermoortele B Bueken G L Bars B V d Voorde

M Vandichel K Houthoofd A Vimont M Daturi M Waroquier V V Speybroeck C Kirschhock D E DeVos J Am Chem Soc 2013 135 11465

[37] A Dhakshinamoorthy H Garcia Chem Soc Rev 2012 41 5262[38] Q Yang Q Xu H-L Jiang Chem Soc Rev 2017 46 4774[39] C N Neumann S J Rozeveld M Yu A J Rieth M Dincă J Am

Chem Soc 2019 141 17477[40] Z Li R Yu J Huang Y Shi D Zhang X Zhong D Wang Y Wu

Y Li Nat Commun 2015 6 8248[41] Y Huang Y Zhang X Chen D Wu Z Yi R Cao Chem Commun

2014 50 10115[42] W Zhan Q Kuang J Zhou X Kong Z Xie L Zheng J Am Chem

Soc 2013 135 1926[43] M Mukoyoshi H Kobayashi K Kusada M Hayashi T Yamada

M Maesato J M Taylor Y Kubota K Kato M Takata

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481

2004481 (8 of 8)

wwwadvancedsciencenewscom

copy 2021 Wiley-VCH GmbH

wwwsmall-journalcom

T Yamamoto S Matsumura H Kitagawa Chem Commun 2015 51 12463

[44] C-H Kuo Y Tang L-Y Chou B T Sneed C N Brodsky Z Zhao C-K Tsung J Am Chem Soc 2012 134 14345

[45] Y Pan Y Qian X Zheng S-Q Chu Y Yang C Ding X Wang S-H Yu H-L Jiang Natl Sci Rev 2020 8 nwaa224

[46] Y Zhao N Kornienko Z Liu C Zhu S Asahina T-R Kuo W Bao C Xie A Hexemer O Terasaki P Yang O M Yaghi J Am Chem Soc 2015 137 2199

[47] G Lu S Li Z Guo O K Farha B G Hauser X Qi Y Wang X Wang S Han X Liu J S DuChene H Zhang Q Zhang X Chen J Ma S C J Loo W D Wei Y Yang J T Hupp F Huo Nat Chem 2012 4 310

[48] I Luz A Loiudice D T Sun W L Queen R Buonsanti Chem Mater 2016 28 3839

[49] Q Yang Q Xu S-H Yu H-L Jiang Angew Chem Int Ed 2016 128 3749

[50] Y Jiang X Zhang X Dai Q Sheng H Zhuo J Yong Y Wang K Yu L Yu C Luan H Wang Y Zhu X Duan P Che Chem Mater 2017 29 6336

[51] K M Choi D Kim B Rungtaweevoranit C A Trickett J T D Barmanbek A S Alshammari P Yang O M Yaghi J Am Chem Soc 2017 139 356

[52] Y-Z Chen Z U Wang H Wang J Lu S-H Yu H-L Jiang J Am Chem Soc 2017 139 2035

[53] N Zhang Q Shao P Wang X Zhu Q Huang Small 2018 14 1704318[54] S Li H-M Mei S-L Yao Z-Y Chen Y-L Lu L Zhang C-Y Su

Chem Sci 2019 10 10577[55] X Deng S Liang X Cai S Huang Z Cheng Y Shi M Pang

P Ma J Lin Nano Lett 2019 19 6772[56] S S Y Chui S M F Lo J P H Charmant A G Orpen

I D Williams Science 1999 283 1148[57] L Maserati S M Meckler C Li B A Helms Chem Mater 2016

28 1581[58] A Dhakshinamoorthy M Alvaro P Concepcion H Garcia

Catal Commun 2011 12 1018[59] D F Zhang H Zhang L Guo K Zheng X-D Han Z Zhang

J Mater Chem 2009 19 5220[60] J-L Zhuang D Ceglarek S Pethuraj A Terfort Adv Funct Mater

2011 21 1442

Small 2021 17 2004481