1

Electronic Supporting Information (ESI)

for

Two microporous MOFs constructed from different metal clusters SBUs for selective gas adsorptionYun-Wu Li,a,b Jian Xu,a Da-Cheng Li,b Jian-Min Dou,b Hui Yan,b Tong-Liang Hu*a and Xian-He Bu*a

aSchool of Materials Science and Engineering, College of Chemistry, TKL of Metal- and

Molecule-Based Material Chemistry, and Collaborative Innovation Center of Chemical Science

and Engineering(Tianjin), Nankai University, Tianjin 300071, P. R.

bSchool of Chemistry and Chemical Engineering, and Shandong Provincial Key Laboratory of

Chemical Energy Storage and Novel Cell Technology, Liaocheng University, Liaocheng 252000,

P. R. China.

*To whom correspondence should be addressed.

E-mail: tlhu@nankai.edu.cn; buxh@nankai.edu.cn

Electronic Supplementary Material (ESI) for Chemical Communications.This journal is © The Royal Society of Chemistry 2015

2

S1. Experimental Section

Materials and methods.

All chemicals were commercially purchased and used as received.

Elemental analyses (C, H, and N) were performed on a Perkin-Elmer 240C analyzer (Perkin-

Elmer, USA). The X-ray powder diffraction (XRPD) was recorded on a Rigaku D/Max-2500

diffractometer at 40 kV, 100 mA for a Cu-target tube and a graphite monochromator. Simulation

of the XRPD spectra were carried out by the single-crystal data and diffraction-crystal module of

the Mercury (Hg) program available free of charge via the Internet at http://www.iucr.org. IR

spectrum was measured in the range of 400-4000 cm-1 on a Tensor 27 OPUS FT-IR spectrometer

using KBr pellets (Bruker, German). The thermogravimetric (TG) analysis was done on a

standard TG-DTA analyzer under N2 atmosphere at a heating rate of 10 °C/min for measurement.

Syntheses of 1 and 2:

The reaction of Zn(NO3)2·6H2O (Cd(NO3)2·4H2O for 2), H3BTC, and H2PDA (H2PDA =

Pyrazine-2,3-dicarboxylic acid) (BTA-AA for 2, BTA-AA=1H-benzotriazole-1-acetic acid)

in DMA at 120 °C for 3 days yielded block-like colorless crystals of 1 (2; for details see

below) The ligands H2PDA and BTA-AA don’t appear in the final structures but they play

important roles in the syntheses of 1 and 2. They act as reaction mediation and fine tuning the

acid-base reaction conditions to promote the formation of 1 and 2. Without H2PDA and BTA-

AA, we only got unknown powder in stead of crystals.

A mixture of Zn(NO3)2·6H2O (89 mg, 0.3 mmol) (Cd(NO3)2·4H2O (92 mg, 0.3 mmol) for 2)),

H3BTC (63 mg, 0.3 mmol), and H2PDA (50 mg, 0.3 mmol) (BTA-AA (71 mg, 0.4 mmol) for 2)

in DMA (6 mL) were sealed in a 23 mL Teflonlined stainless steel container, which was heated at

120 °C for 3 days and then cooled to room temperature at a rate of 10 °C·h-1. Colourless block

shaped crystals of 1 and 2 were collected. Yield: 25% for 1 and 28% for 2 based on Zn and Cd,

respectively. Elemental analysis (%) for 1, C74H83N7O44Zn9 (M = 2361.15): Calcd.: C, 37.61; H,

3.54; N, 4.15; Found: C, 37.65; H, 3.51; N, 4.18. For 2, C15H20N2O7Cd (M = 452.73): Calcd.: C,

37.61; H, 3.54; N, 4.15; Found: C, 37.65; H, 3.59; N, 4.19.

X-ray Crystallography.

The crystallographic data of 1 and 2 were collected on a Rigaku SCX-mini diffractometer at

293(2) K with Mo-Kα radiation (λ = 0.71073 Å). The crystal data were solved by direct methods

and refined by a full-matrix least-square method on F2 using the SHELXL-97 crystallographic

3

software package.S1 Zn and Cd atoms in 1 and 2 were found from E-maps and other non-

hydrogen atoms were located in successive difference Fourier syntheses. The final refinement

was performed by full matrix least-squares methods with anisotropic thermal parameters for non-

hydrogen atoms on F2. The hydrogen atoms of organic ligands for 1, 2, [NH2(CH3)2]+ cations and

solvents DMA for 2 were added theoretically, riding on the concerned atoms and refined with

fixed thermal factors. The H atoms of the coordinated water molecules in 1 cannot be added in

the calculated positions, and they were directly included in the final molecular formula. For 1, the

[NH2(CH3)2]+ cations and solvents DMA molecules were highly disordered and could not be

modeled properly, thus the SQUEEZE routine of PLATON was applied to remove their

contributions of the scattering. The results were appended in the CIF file. The reported

refinements are of the guest-free structures using the *.hkp files produced using the SQUEEZE

routine.S2,S3 The residual electron densities were assigned to some dimethylamine cations and

solvent DMA molecules. So SQUEEZE removed the dimethylamine cations and solvent DMA

molecules per unit cell. This value calculated based upon charge balance considerations,

volume/count electrons analysis combining with EA analyses. Furthermore, the presence of

[NH2(CH3)2]+ are also certified by the 1H NMR, IR spectroscopy and TG analysis. The 1H NMR

spectrum of 1 recorded in D2O exhibits a signal at 2.54 ppm can be ascribed to the CH3 group of

[NH2(CH3)2]+.S4 The IR spectra of 1 exhibit peaks at 3445 and 3530 cm-1 is attributed to the

asymmetrical and symmetrical of N-H absorption vibration of [NH2(CH3)2]+. The peaks at 1763,

1621, 1574 cm-1 are assigned to the N–H stretching vibrations of amine group. The peak at 2797

cm-1 is corresponded to the C-H stretching frequency of [NH2(CH3)2]+.S5 So [NH2(CH3)2]+

cations and solvents DMA molecules cannot be added in the calculated positions. They were

directly included in the final molecular formula. During the refinement of the two compounds,

the command “omit -3 50” was used to omit some disagreeable reflections. The atoms O1w, O6

in 1, and the O5, C13 in 2 were restrained using thermal restraints (isor) to make the

displacement parameters more reasonable. Further details of crystal data and structure refinement

for 1 and 2 were summarized as follows in Table S1. Selected bond lengths of 1 and 2 were given

in Table S2 and S3. Full crystallographic data for 1 and 2 have been deposited with the CCDC

(1060331 for 1, and 1060332 for 2). These data can be obtained free of charge from The

Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.S6

References

4

S1 (a) G. M. Sheldrick, SHELXL97, Program for Crystal Structure Refinement; University of

Göttingen: Göttingen, Germany, 1997; (b) G. M. Sheldrick, SHELXS97, Program for

Crystal Structure Solution; University of Göttingen: Göttingen, Germany, 1997.

S2 A. L. Spek, PLATON, A Multipurpose Crystallographic Tool, Untrecht University, 2003.

S3 (a) O. V. Dolomanov, D. B. Cordes, N. R. Champness, A. J. Blake, L. R. Hanton, G. B.

Jameson, M. Schroder and C. Wilson. Chem. Commun., 2004, 642; (b) Y. Du, A. L.

Thompson and D. O. Hare. Chem. Commun., 2008, 5987; (c) Y. F. Bi, X. T. Wang, W. P.

Liao, X. F. Wang, X. W. Wang, H. J. Zhang and S. Gao, J. Am. Chem. Soc., 2009, 131,

11650; (d) W. X. Zhang, W. Xue, J. B. Lin, Y. Z. Zheng and X. M. Chen, CrystEngComm,

2008, 10, 1770 and so on.

S4 (a) L. Carlucci, G. Ciani, D. M. Proserpio, F. Porta, Angew. Chem. Int. Ed., 2003, 42, 317; (b)

R. P. Davies, R. Less, P. D. Lickiss, K. Robertson and A. J. P. White, Crys. Growth & Des.,

2010, 10, 4571.

S5 (a) J. D. Lin, S. T. Wu, Z. H. Li and S. W. Du, Dalton Trans., 2010, 39, 10719; (b) A.

Karmakar, S. Hazra, M. F. C. G. Silva and A. J. L. Pombeiro, Dalton Trans. , 2015, 44, 268;

(c) W. M. Liao, H. T. Shi, X. H. Shi and Y. G. Yin, Dalton Trans., 2014, 43, 15305.

S6 The checkcif program available at: http://journals.iucr.org/services/cif/checkcif.html.

5

Crystal data for 1 and 2

Table S1. Crystal Data and Structure Refinement Parameters for Compounds 1–2.

compound 1 2

formula C74H83N7O44Zn9 C15H20N2O7Cd

Fw 2363.15 452.73λ/Å 0.71073 0.71073

T/K 293(2) 293(2)

crystal system Cubic Monoclinic

space group I23 P21/n

a [Å] 23.503(3) 10.099(2)

b [Å] 23.503(3) 14.363(3)

c [Å] 23.503(3) 12.975(3)

α[°] 90 90

β [°] 90 105.69(3)

γ[°] 90 90

V ( Å 3) 12983(3) 1812.0(6)

Z 4 4

Dc/Mg·m-3 0.978 1.660

F(000) 3759 912

reflections collected/unique 52094/3819 15434/3173

Rint 0.1211 0.0366

data / restraints / parameters 3819/12/158 3173/12/243

R1/wR2 [I>2σ(I)] a 0.0846/0.2050 0.0299/0.0586

R1/wR2 [(all data)] a 0.0993/0.2141 0.0370/0.0606

GOF on F2 1.110 1.156a R1 = Σ(||F0| – |FC||)/Σ|F0| wR2 = [Σw(|F0|2 – |FC|2)2/(Σw|F0|2)2]1/2.

6

Sorption measurements.

Gas adsorption/desorption measurements were carried out using a Micrometrics ASAP

2020M volumetric gas adsorption instrument. UHP-grade gases were used in measurements.

Before the measurement, the samples of 1 and 2 were soaked in anhydrous methanol (CH3OH)

for 3 days to remove DMA solvent molecules in the channels, and then filtrated, and activation of

the methanol-exchanged 1 and 2 at 120 °C under high vacuum (less than 10-5 Torr) overnight led

to the formation of activated sample 1a and 2a. About 280 mg (for 1) and 165 mg (for 2) of the

desolvated samples were used for the entire adsorption/desorption measurements. The Ar

adsorption/desorption isotherm measurements were proceeded at 77 K in a liquid nitrogen bath.

The H2 adsorption/desorption isotherms were collected at 77 K in a liquid nitrogen bath and 87 K

in a liquid argon bath. The CO2, CH4 and N2 adsorption/desorption isotherm measurements were

carried out at 273 K in an ice-water bath, respectively.

7

S2. Figures in Supporting Information

Fig. S1 PXRD patterns for 1, 1a, 2 and 2a.

8

Fig S2 The TG curves of 1 and 1a.

Fig S3 The TG curves of 2 and 2a.

9

Fig. S4 The PXRD patterns of the simulated patterns, after immersed in deionized water,

C2H5OH and acetone for 1.

Fig. S5 The PXRD patterns of the simulated patterns, after immersed in deionized water,

C2H5OH and acetone for 2.

10

Fig. S6 IR spectra of compounds 1 and 2.

11

Fig. S7 Pore size distributions of 1a and 2a.

12

Fig. S8 H2 adsorption enthalpies for 1a and 2a calculated from the H2 adsorption isotherms at 77

K and 87 K.

Fig.S9 CO2 adsorption enthalpies for 1a and 2a calculated from the CO2 adsorption isotherms at

273 K and 298 K.

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S3. IAST adsorption selectivity calculation:S7-S9

The experimental isotherm data for pure CO2, CH4 and N2 (measured at 273 K) were fitted using

a Langmuir-Freundlich (L-F) model:

c

c

Pbpbaq

1

Where q and p are adsorbed amounts and pressures of component i, respectively.

Using the pure component isotherm fits, the adsorption selectivity is defined by

2

1

2

1

pp

qq

Sads

Where qi is the amount of i adsorbed and pi is the partial pressure of i in the mixture.

We used the following written codes to simulate the adsorption selectivity of CO2 over CH4 or N2

in Fig. 4:

28 # No. of Pressure Point

y1, y2 # Molar fraction of binary mixture (y1 and y2, y1 + y2 = 1)

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 101, 102, 103, 104, 105, 106, 107,

108, 109 #The unit is same parameter b, kPa

a1, a2 # fitting parameter Nsat (A1) for both component (Unit: mmol/g)

b1, b2 # fitting parameter b1 for both components (Unit: kPa-1)

c1, c2 # fitting parameter c1 for both components

0, 0 # fitting parameter Nsat2(A2) for both component(Unit: mmol/g)

0, 0 # fitting parameter b2 for both components (Unit: kPa-1)

1, 1 # fitting parameter c2 for both components

14

Fig. S10 N2, CH4 and CO2 adsorption isotherms of 1a with fitting by L-F model.

15

Fig. S11 CH4 and CO2 adsorption isotherms of 2a with fitting by L-F model.

16

Fig. S12 IAST adsorption selectivities of (a) (b) 1a and (c) 2a.

S7 F. Daniels, R. A. Alberty, J. W. Williams, C. D. Cornwell, P. Bender and J. E. Harriman,

Experimental Physical Chemistry, 6th Ed, McGraw-Hill Book Co. Inc., New York, 1962.

S8 M. Dincă and J. R. Long, J. Am. Chem. Soc., 2005, 127, 9376.

S9 D. C. Zhong, J. B. Lin, W. G. Lu, L. Jiang and T. B. Lu, Inorg. Chem., 2009, 48, 8656.

17

S4 The computational simulation studies of gases adsorption

The GCMC simulations were performed by the Sorption program, Locate task and Metropolis

method in the Materials Studio modeling 5.0 package. The framework and the individual CO2

molecules were considered to be rigid.

In order to explain the selectivity of CO2 adsorption for 1a and 2a, CO2 binding sites were

simulated with grand canonical Monte Carlo (GCMC) using Materials Studio.9e,15b,S10 As

shown in Fig. S13 and S14, the most preferential binding sites of the two compounds are

different. In 1a, the CO2 molecules locate around both of the OMSs hanging on the dimeric

Zn(II)-cluster (Fig. S13a) (C···Zn = 4.17 Å) and the [NH2(CH3)2]+ (C···N = 4.23 Å) (Fig.

S13b), indicating that there are stronger binding interactions for both of them than the other

active sites. While in 2a, the CO2 molecules locate around the [NH2(CH3)2]+ (C···N = 3.95 Å)

which embedded in the small neck (Fig. S14), suggests there is stronger binding interaction

between them. These simulated results show good agreement with the experimental values.

Fig. S13 Preferential CO2 locations in 1a obtained from GCMC calculations.

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Fig. S14 Preferential CO2 location in 2a obtained from GCMC calculations.

S10 (a) Accelrys, Materials Studio Getting Started, release 5.0; Accelrys Software, Inc.: San

Diego, CA, 2009; (b) J. B. Lin, J. P. Zhang and X. M. Chen, J. Am. Chem. Soc., 2010, 132,

6654.

19

S5. The selected bond lengths [Å] and angles [º] of compounds 1 and 2.

Table S2 The selected bond lengths [Å] and angles [º] of compound 1.

Zn(1)-O(1W) 1.971(1) Zn(2)-O(3) 1.984(7) Zn(1)-O(1) 2.029(7) Zn(2)-O(2W) 1.993(4) Zn(1)-O(1)#1 2.029(7) O(2)-Zn(1)#2 2.071(6) Zn(1)-O(2)#2 2.071(6) O(4)-Zn(2)#6 1.937(7) Zn(1)-O(2)#3 2.071(6) O(5)-Zn(2)#7 1.909(7) Zn(1)-Zn(1)#2 2.990(2) O(2W)-Zn(2)#5 1.993(4) Zn(2)-O(5)#4 1.909(7) O(2W)-Zn(2)#6 1.993(4) Zn(2)-O(4)#5 1.937(7)

O(1W)-Zn(1)-O(1) 100.8(2) O(2)#2-Zn(1)-O(2)#3 159.2(4) O(1W)-Zn(1)-O(1)#1 100.8(2) O(5)#4-Zn(2)-O(4)#5 120.1(4) O(1)-Zn(1)-O(1)#1 158.4(4) O(5)#4-Zn(2)-O(3) 103.2(4) O(1W)-Zn(1)-O(2)#2 100.4(2) O(4)#5-Zn(2)-O(3) 101.8(3) O(1)-Zn(1)-O(2)#2 88.0(3) O(5)#4-Zn(2)-O(2W) 113.3(5) O(1)#1-Zn(1)-O(2)#2 88.2(3) O(4)#5-Zn(2)-O(2W) 109.3(3) O(1W)-Zn(1)-O(2)#3 100.4(2) O(3)-Zn(2)-O(2W) 107.6(3)O(1)-Zn(1)-O(2)#3 88.2(3) O(1)#1-Zn(1)-O(2)#3 88.0(3)

Symmetry transformations used to generate equivalent atoms: #1: -x+1, -y+2, z; #2: x, -y+2, -z+2; #3: -x+1, y, -z+2; #4: -y+3/2, z-1/2, -x+3/2; #5: z, x, y; #6: y, z, x; #7: -z+3/2, -x+3/2, y+1/2.

Table S3 The selected bond lengths [Å] and angles [º] of compound 2.

O(6)-Cd(1)#1 2.225(3) Cd(1)-O(1) 2.217(2) O(4)-Cd(1)#2 2.238(2) Cd(1)-O(6)#5 2.225(3) O(3)-Cd(1)#3 2.259(2) Cd(1)-O(4)#6 2.238(2) O(2)-Cd(1)#4 2.320(3) Cd(1)-O(3)#7 2.259(2) Cd(1)-O(2)#4 2.320(2)

O(1)-Cd(1)-O(6)#5 129.49(10) O(4)#6-Cd(1)-O(3)#7 150.83(11) O(1)-Cd(1)-O(4)#6 95.05(11) O(1)-Cd(1)-O(2)#4 151.81(10) O(6)#5-Cd(1)-O(4)#6 99.85(10) O(6)#5-Cd(1)-O(2)#4 78.48(10) O(1)-Cd(1)-O(3)#7 90.86(10) O(4)#6-Cd(1)-O(2)#4 81.32(12) O(6)#5-Cd(1)-O(3)#7 98.23(10) O(3)#7-Cd(1)-O(2)#4 80.10(11)

Symmetry transformations used to generate equivalent atoms: #1: x-1, y, z; #2: -x+3/2, y+1/2, -z+1/2; #3: x-1/2, -y+1/2, z-1/2; #4: -x+2, -y, -z+1; #5: x+1, y, z; #6: -x+3/2, y-1/2, -z+1/2; #7: x+1/2, -y+1/2, z+1/2.