selective co adsorption in a metal–organic framework

Supporting Information

Selective CO2 adsorption in a metal–organic framework

constructed from organic ligand with flexible joints

Dae Ho Hong and Myunghyun Paik Suh*

Contribution from the Department of Chemistry, Seoul National University, Seoul 151-747, Republic of Korea

E-mail: [email protected]

Electronic Supplementary Material (ESI) for Chemical CommunicationsThis journal is © The Royal Society of Chemistry 2012

General Method. All chemicals and solvents used in the synthesis were of reagent grade and

used without further purification. Infrared spectra were recorded with a PerkinElmer

Spectrum One FT-IR spectrophotometer. Elemental analyses were performed with a

PerkinElmer 2400 Series II CHN Analyzer. NMR spectra were measured on a Bruker

Advance DPX-300. Thermogravimetric analyses (TGA) and differential scanning calorimetry

(DSC) were performed under N2 (g) at a scan rate of 5 °C min-1, using a TGA Q50 and a DSC

Q10 of TA Instruments, respectively. Powder X-ray diffraction data were recorded on a

Bruker New D8 Advance diffractometer at 40 kV and 40 mA for Cu Kα (λ = 1.54050 Å),

with a scan speed of 0.5s per step and a step size of 0.02º in 2 θ.

Preparation of 1,1'-[benzene-1,4-diylbis(oxy)]bis(3-methylbenzene).[S1] To a mixture of

m-cresol (24 mL, 0.23 mol) and KOH (12 g, 0.21 mol) heated at 200 oC for 10 min, were

added 1,4-dibromobenzene (12 g, 0.05 mol) and copper powder (2.0 g, 0.03 mol). The

reaction mixture was heated at reflux for 12 h to afford black oil, which was dissolved in

ether (300 mL), washed with brine (200 mL × 3), dried over anhydrous MgSO4, and

concentrated under reduced pressure. Resulting yellow oil was purified by column

chromatography (EA : hexane = 1 : 4.25), and the eluate was dried in vacuo to obtain white

powder (5.7 g, 40%). δH (300 MHz; CD2Cl2) 2.37 (6 H, s, Me), 6.84 (2 H, d, Ph), 6.88 (2 H, s,

Ph), 6.96 (2 H, d, Ph), 7.03 (4 H, s, Ph), 7.26 ppm (2 H, t, Ph).

Preparation of 3,3'-(1,4-phenylenebis(oxy))dibenzoic acid (H2mpm-PBODB). Hot

aqueous solution (50 mL) of KMnO4 (12 g, 76 mmol) was slowly added to the pyridine

solution (50 mL) of 1,4-bis(m-tolyloxy)benzene (3.0 g, 10 mmol). The reaction mixture was

heated at 80 oC for 16 h. Brown MnO2 was removed by filtration while hot, washed with hot

water (50 mL), and the filtrate was completely evaporated under reduced pressure. Resulting

white solid was dissolved in water (100 mL), and conc. HCl was added to the solution until

the pH became 1. White precipitate was collected by filtration, washed thoroughly with water

(20 mL × 3), and dried under vacuum to yield white powder (1.8 g, 53%). FTIR (KBr pellet)

νmax/cm-1 1686, 1611 (COOH); δH (300 MHz; d6-DMSO) 7.13 (4 H, s, Ph), 7.31 (2 H, d, Ph),

7.47 (2 H, s, Ph), 7.51 (2 H, t, Ph), 7.71 (2 H, d, Ph), 13.14 ppm (2 H, s, COOH).

Synthesis of {[Zn2(mpm-PBODB)2bpy]·3DMF}n (SNU-110). Zn(NO3)2·6H2O (150 mg,

0.50 mmol) and H2mpm-PBODB (176 mg, 0.50 mmol) were dissolved in DMF (10 mL), and

the solution was heated at 90 oC for 12 h. After the solution was cooled to room


temperature, 4,4’-bpy (39 mg, 0.25 mmol) was added and then heated again at 90 oC for 48 h.

The crystals formed were filtered off, washed with DMF, and dried briefly in air (160 mg,

53%). FTIR (Nujol mull) νmax/cm-1 1584, 1607 (Ph–O–Ph), 1644 (O–C=O), 1669

(C=O(DMF)); elemental analysis found: C 58.76, H 4.20, N 5.91, calc. for C59H53N5O15Zn2:

C 58.91, H 4.44, N 5.82%.

Preparation of [Zn2(mpm-PBODB)2bpy]n (SNU-110’) by the supercritical drying

method. Prior to drying, the mother liquor of as-synthesized SNU-110, was decanted and the

crystals were washed briefly with DMF (15 mL × 3). The crystals were placed inside the

supercritical dryer together with the solvent and the drying chamber was sealed. The

temperature and pressure of the chamber were raised to 40 oC and 200 bar with CO2, above

the critical point (31 oC, 73 atm) of CO2. The chamber was vented at a rate of 5 mL min-1 and

then filled with CO2 again. The cycles of refilling with CO2, pressurizing, and venting were

repeated for 4 h. After drying, the closed container with the dried crystals (SNU-110’) was

transferred to a glove bag filled with Ar gas to prevent exposure of the crystals to air. The gas

sorption isotherms were measured without further activation. FTIR (Nujol mull) νmax/cm-1

1570, 1610 (Ph–O–Ph), 1632 (O–C=O); elemental analysis found: C 60.64, H 3.19 N 3.10.

calc. for C59H53N5O15Zn2: C 61.06, H 3.28, N 2.85.

Low-Pressure Gas Sorption Measurements. The gas adsorption-desorption data were

measured by an automated micropore gas analyzer Autosorb-1 or Autosorb-3B

(Quantachrome Instruments). All gases used were of 99.9999% purity. Sample was activated

by supercritical CO2 as described above and transferred to a gas sorption cell in a glove bag

filled with Ar gas to prevent exposure to air. The N2 gas isotherms were measured at 77 K,

195 K, and 298 K. The O2 gas isotherms were measured at 77 K. The H2 gas isotherms were

measured at 77 K and 195 K, and the CO2 and CH4 gas sorption isotherms were monitored at

195, 231, 273, and 298 K at each equilibrium pressure by the static volumetric method. After

gas sorption measurement, the weight of sample was measured again precisely. Surface area

and pore volume were calculated from CO2 adsorption/desorption data measured at 195 K

using DR method, by taking the data in the range of P = 0.001 – 0.006 atm and P = 0.008 –

0.05 atm, respectively.

X-ray Crystallographic Analysis. A crystal of SNU-110 was coated with paratone-N oil and

the diffraction data were measured at 95 K with synchrotron radiation (λ = 0.65000 Å) on an


ADSC Quantum-210 detector at 2D SMC with a silicon (111) double crystal monochromator

(DCM) at the Pohang Accelerator Laboratory, Korea. The ADSC Q210 ADX program[S2] was

used for data collection (detector distance, 62 mm; omega scan; Δω = 1º, exposure time, 3.0

sec per frame), and HKL3000sm (Ver. 703r)[S3] was used for cell refinement, reduction, and

absorption correction. The crystal structure of SNU-110 was solved by direct methods[S4] and

refined by full-matrix least-square refinement using SHELXL-97 program.[S5] The hydrogen

atoms were positioned geometrically by using a riding model. CCDC-885397 contains the

supplementary crystallographic data for this paper. This data can be obtained free of charge

from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif/.

The crystallographic data for SNU-110 is summarized in Table S1.

Measurement of Powder X-ray Diffraction Data for [Zn2(mpm-PBODB)2bpy]n (SNU-

110’). A sample was prepared in borosilicate glass capillary (diameter: 0.7 mm, wall

thickness: 0.01 mm) and mounted on capillary station with rotation speed of 30 rpm. Powder

X-ray diffraction data were recorded on a Bruker D8 Advance diffractometer with a Goebel

mirror, selecting the Cu Kα (λ = 1.5418 Å; weighed average of Cu Kα1 and Cu Kα2 radiation),

with a scan speed of 2 s per step and a step size of 0.02° in 2 θ at 298 K.

Measurement of Powder X-ray Diffraction Data for [Zn2(mpm-PBODB)2bpy]n (SNU-

110’) under CO2 pressure. Cold CO2 gas stream was generated from dry ice and provided

over the sample. Dry ice was placed beneath the sample holder to keep the temperature of the

sample at 248 K. X-ray diffraction data were recorded on a Bruker New D8 Advance

diffractometer at 40 kV and 40 mA for Cu Kα (λ = 1.54050 Å), with a scan speed of 0.5s per

step and a step size of 0.02º in 2 θ.

References:

[S1] Ullmann, F., Sponagel P., Berichte der deutschen chemischen Gesellschaft, 1905, 38 (2), 2211–

2212.

[S2] Arvai, A. J., Nielsen, C. ADSC Quantum-210 ADX Program, Area Detector System Corporation;

Poway, CA, USA, 1983.

[S3] Otwinowski, Z., Minor, W., in Methods in Enzymology, ed. Carter, Jr., C. W.; Sweet, R. M.

Academic Press, New York, 1997, vol. 276, part A, pp. 307.

[S4] Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112-122.

[S5] Sheldrick, G. M. SHELEX97, Program for the crystal structure refinement; University of

Göttingen: Göttingen, Germany, 1997.


Fig. S1. An ORTEP drawing of SNU-110, showing the coordination environment of Zn2

paddle-wheel unit. Thermal ellipsoids are drawn with 30% probability. Symmetry

transformations: a, -x+2, -y+1, -z+2; b, x-1, -y+3/2, z-1/2; c, -x+3, y-1/2, -z+5/2; d, -x+1, -

y+1, -z+1.


Fig. S2. TGA/DSC trace for SNU-110 (blue and green) and SNU-110’ (red).


Fig. S3. Pawley refinement of the SNU-110’. Red crosses: experimental diffraction data, blue

line: calculated results, black line: difference plot, green mark: Bragg positions.

Fig. S4. CO2 adsorption isotherms of SNU-110’ at various temperatures.


Fig. S5. CO2 adsorption isotherms of SNU-110’ at various temperatures. The relative

pressures (P/P0) occurring the phase transition are 0.48 at 195 K, 0.021 at 231 K, 0.0044 at

273 K, and 0.0036 at 298 K, as marked by an arrow.


Fig. S6. Plot of isosteric heats of adsorption vs CO2 uptake in SNU-110’.

Fig. S7. Adsorption isotherms of SNU-110’ for CO2 (brown), CH4 (red), and N2 (blue)

measured at 298 K.


Table S1. Crystallographic data for SNU-110 (Squeezed).

SNU-110

Formula Zn2 C56 H46 N4 O14

Crystal system Monoclinic

Space group P 21/c

Formula weight 1967.03

a, Å 13.289(3)

b, Å 16.467(3)

c, Å 13.711(3)

117.02(3)

V, Å3 2673.0(9)

Z 2

ρcalcd, g cm-3 1.404

T, K 95(2)

λ, Å 0.65000

μ, mm-1 0.967

Goodness-of-fit on F2 1.065

F(000) 1164

Reflections collected 10576

Independent reflections 9689 [R(int) = 0.0459]

Completeness to θ = 27.5° 93.70%

Data / restraints / parameters 9689 / 0 / 343

θ range for data collection, ° 1.94 to 33.39

Diffraction limits (h, k, l)

-22<=h<=22,

-25<=k<=25,

-22<=l<=22

Refinement method Full-matrix least-squares on F2

R1, wR2 [I > 2σ(I)] 0.0459,a 0.149b

R1, wR2 (all data) 0.0527,a 0.1537b

Largest diff. peak and hole, e Å-3 0.993, -2.1

aR = F0- Fc/F0.b wR(F2) = [w(Fo2

– Fc2)2/w(Fo

2)2]½ where w = 1/[ σ2(Fo2) + (0.0978 P)2 +

(1.4973)P], P = (Fo2 + 2Fc

2)/3


Table S2. Cell parameters of SNU-110 and SNU-110’ obtained from single crystal X-ray

diffraction data and from simulation of PXRD pattern, respectively.

a [Å] b [Å] c [Å] α [°] β [°] γ [°] V [Å3]

SNU-110 (Monoclinic, P21/c)

13.289 16.467 13.711 90 117.02 90 2673.0

SNU-110’ (Triclinic, P1)a

10.7051 20.1517 14.4029 103.808 123.559 93.739 2438.59

a The cell parameters are cyclically permutated for comparison. (abc → cab)


Table S3. CO2 Adsorption and Desorption Data in SNU-110’ at 195, 231, 273, and 298 K

CO2 at 195 K CO2 at 231 K

P / atm Vads

/ cc g-1 P / atm

Vdes / cc g-1

P / atm Vads

/ cc g-1 P / atm

Vdes / cc g-1

1.12E-04 0.0056 8.93E-01 96.5038 9.97E-05 0.0512 9.99E-01 36.984 3.18E-04 0.6181 8.39E-01 96.1979 1.96E-04 0.1052 9.42E-01 36.6992 3.21E-04 0.6213 7.89E-01 95.884 3.01E-04 0.1672 8.89E-01 36.3381 4.14E-04 0.7498 7.39E-01 95.4591 3.98E-04 0.2196 8.39E-01 35.9511 7.41E-04 1.2647 6.89E-01 95.1012 4.99E-04 0.2812 7.89E-01 35.5418 6.75E-04 1.26 6.40E-01 94.5989 6.01E-04 0.3408 7.39E-01 35.1108 7.02E-04 1.3583 5.90E-01 94.1328 6.99E-04 0.3914 6.89E-01 34.6613 1.02E-03 1.8499 5.39E-01 93.7594 7.98E-04 0.4441 6.39E-01 34.1775 9.42E-04 1.8571 4.90E-01 93.1105 8.98E-04 0.4984 5.90E-01 33.6765 1.23E-03 2.3689 4.39E-01 92.6654 1.01E-03 0.537 5.40E-01 33.1297 2.02E-03 4.1645 3.90E-01 91.9802 2.10E-03 1.0523 4.90E-01 32.5462 3.08E-03 6.3454 3.41E-01 91.248 3.06E-03 1.5178 4.40E-01 31.9098 4.01E-03 7.7319 2.91E-01 90.3879 4.09E-03 2.0684 3.90E-01 31.2124 5.12E-03 8.9751 2.43E-01 89.1985 5.04E-03 2.6117 3.41E-01 30.4124 6.22E-03 9.6371 1.91E-01 88.4536 6.03E-03 3.2456 2.91E-01 29.4593 7.08E-03 9.8753 1.42E-01 87.0358 7.03E-03 3.9722 2.43E-01 28.0233 8.38E-03 11.9734 9.61E-02 84.589 8.02E-03 4.7971 1.95E-01 26.1965 9.06E-03 12.3431 5.15E-02 80.3219 9.03E-03 5.7037 1.44E-01 24.6423 1.13E-02 12.7408 3.34E-02 75.8018 1.01E-02 6.7412 1.95E-02 14.1419 2.10E-02 68.7594 2.12E-02 10.3747 2.99E-02 15.5139 8.34E-03 43.3178 2.94E-02 12.5837 4.10E-02 16.6738 4.03E-02 14.678 5.65E-02 17.6525 5.05E-02 16.0987 6.08E-02 18.0512 6.14E-02 17.3666 7.00E-02 18.6606 6.98E-02 18.1069 7.98E-02 19.2439 7.97E-02 18.8588 9.01E-02 19.8065 9.01E-02 19.5363 1.08E-01 20.5641 1.08E-01 20.4539 1.53E-01 22.1583 1.55E-01 22.188 2.03E-01 23.7185 2.06E-01 23.781 2.57E-01 24.7427 2.55E-01 25.7773 3.04E-01 26.3386 3.06E-01 27.3757 3.56E-01 27.6489 3.58E-01 28.4266 4.04E-01 29.0946 4.09E-01 29.3024 4.49E-01 31.4926 4.59E-01 30.0809 5.00E-01 36.1341 5.09E-01 30.806 5.52E-01 54.271 5.59E-01 31.4791


5.98E-01 70.4605 6.10E-01 32.1259 6.47E-01 81.1826 6.60E-01 32.7466 7.04E-01 88.2095 7.10E-01 33.3508 7.58E-01 91.7732 7.60E-01 33.9492 8.01E-01 93.8359 8.10E-01 34.5497 8.55E-01 95.2347 8.60E-01 35.1688 9.08E-01 96.1701 9.10E-01 35.7759 9.58E-01 96.9792 9.59E-01 36.4113

9.99E-01 36.984


Table 3 (continued)

CO2 at 273 K CO2 at 298 K

P / atm Vads

/ cc g-1 P / atm

Vdes / cc g-1

P / atm Vads

/ cc g-1 P / atm

Vdes / cc g-1

1.03E-03 0.0151 9.99E-01 23.5775 6.25E-02 0.0381 9.99E-01 12.382 2.07E-03 0.041 9.42E-01 23.0292 7.25E-02 0.1609 9.42E-01 11.8809 3.15E-03 0.0648 8.90E-01 22.5327 8.25E-02 0.3 8.89E-01 11.4612 4.22E-03 0.0891 8.40E-01 22.014 9.24E-02 0.4393 8.39E-01 11.0605 5.29E-03 0.1136 7.90E-01 21.4527 1.11E-01 0.6625 7.89E-01 10.6403 6.36E-03 0.1385 7.40E-01 20.8359 1.60E-01 1.2225 7.39E-01 10.2129 7.42E-03 0.1645 6.90E-01 20.161 2.10E-01 1.8213 6.89E-01 9.7841 8.49E-03 0.1897 6.41E-01 19.4129 2.59E-01 2.6714 6.39E-01 9.3406 9.56E-03 0.2156 5.91E-01 18.5833 3.07E-01 4.004 5.89E-01 8.8936 1.06E-02 0.24 5.41E-01 17.6396 3.59E-01 5.1043 5.39E-01 8.416 2.20E-02 0.5385 4.92E-01 16.5794 4.10E-01 5.796 4.89E-01 7.919 3.21E-02 0.7996 4.43E-01 15.373 4.60E-01 6.3975 4.39E-01 7.4025 4.21E-02 1.0576 3.93E-01 13.9921 5.10E-01 6.9551 3.90E-01 6.8414 5.22E-02 1.3064 3.44E-01 12.4296 5.60E-01 7.4934 3.40E-01 6.2045 6.21E-02 1.5633 2.95E-01 10.6686 6.10E-01 8.0276 2.91E-01 5.3132 7.22E-02 1.8213 2.46E-01 8.5131 6.60E-01 8.5625 2.42E-01 4.0296 8.21E-02 2.0742 1.96E-01 6.2565 7.10E-01 9.0959 1.91E-01 3.0381 9.21E-02 2.3396 1.44E-01 4.617 7.60E-01 9.6235 1.40E-01 2.3632 1.10E-01 2.8121 9.30E-02 3.2103 8.10E-01 10.1712 9.01E-02 1.7362 1.58E-01 4.0831 3.85E-02 1.6472 8.60E-01 10.7251 3.44E-02 0.9284 2.06E-01 5.5928 9.10E-01 11.2775 2.54E-01 7.8055 9.60E-01 11.8506 3.04E-01 10.0435 9.99E-01 12.382 3.55E-01 11.8685 4.06E-01 13.4629 4.57E-01 14.8727 5.07E-01 16.1004 5.58E-01 17.1742 6.08E-01 18.1456 6.59E-01 19.0187 7.09E-01 19.8144 7.59E-01 20.5497 8.09E-01 21.2482 8.60E-01 21.8826 9.10E-01 22.5072 9.60E-01 23.0743 9.99E-01 23.5775


selective co adsorption in a metal–organic framework

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