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Electronic supplementary information (ESI)
Zinc(II) and cadmium(II) metal-organic frameworks with 4-imidazole
containing tripodal ligand: sorption and anion exchange properties†
Shui-Sheng Chen,a,b
Peng Wang,a Satoshi Takamizawa,
c Taka-aki Okamura,
d Min Chen
a and
Wei-Yin Sun*a
a Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, School
of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures,
Nanjing University, Nanjing 210093, China. E-mail: [email protected]; Fax: +86 25
83314502
b School of Chemistry and Chemical Engineering, Fuyang Teachers College, Fuyang 236041,
China
c International Graduate School of Arts and Sciences, Yokohama City University,
Kanazawa-ku, Yokohama, Kanagawa 236-0027, Japan
d Department of Macromolecular Science, Graduate School of Science, Osaka University,
Toyonaka, Osaka 560-0043, Japan
Table S1. Selected bond lengths [Å] and bond angles [º] for complexes 1 and 2
1
Zn(1)-N(1) 2.008(2) Zn(1)-N(2)#1 1.970(2)
Zn(1)-N(6)#2 1.979(2) Zn(1)-N(4)#3 2.015(2)
N(2)#1-Zn(1)-N(6)#2 111.57(10) N(2)#1-Zn(1)-N(1) 115.18(10)
N(6)#2-Zn(1)-N(1) 110.64(10) N(2)#1-Zn(1)-N(4)#3 107.69(10)
N(6)#2-Zn(1)-N(4)#3 111.62(10) N(1)-Zn(1)-N(4)#3 99.51(10)
2
Cd(1)-N(12) 2.337(4)
N(12)-Cd(1)-N(12)#4 88.86(15)
Symmetry transformations used to generate equivalent atoms: #1 -y+5/4,x+3/4,z-1/4, #2
-x+1,-y+2,-z+2, #3 -x+1/2,-y+2,z+1/2, #4 -z+1/2,-x+1,y+1/2-1.
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Computational Details.
In the simulations, atomic partial charges for the frameworks are computed from the
ChelpG method as Yang et al.1 DFT calculations using the UB3LYP functional were carried
out to compute the charge distributions, and the basis set LANL2DZ was used for the metal
atoms Co and Zn, while 6-31+G* was used for the remaining atoms. All the calculations were
performed using the GAUSSIAN 03 programs.2 ChelpG charge is listed by the atomic label
given in Scheme 1 and Table S2.
The adsorption isotherms were simulated with grand canonical Monte Carlo (GCMC)
simulations with Towhee Code.3 Detailed descriptions of the simulation method are given in
the references.4 In the grand canonical ensemble, the chemical potential of each component,
temperature, and volume are kept constant as in adsorption experiments. For the sorbate
molecules as well as for the frameworks 1′, 3' and 4', atomistic models were employed.
Interactions beyond 0.75, 0.74 and 0.495 nm were neglected for 1′, 3' and 4', respectively.
The Lorentz-Berthelot (LJ) mixing rules were used to calculate mixed LJ parameters.5 For
methane, the van der Waals interactions between the sorbate molecules themselves as well as
between the sorbate molecules and the frameworks were described with the LJ potential only.
Methane was described with a united atom description, with the potential parameters for
methane were taken from Goodbody et. al.6 (σCH4 = 0.373 nm, εCH4/kB = 148 K). A
combination of the LJ and Coulombic potentials was used to describe the van der Waals
interaction for other sorbate molecules except methane. Hydrogen was treated as a diatomic
molecule modeled with parameters (σH = 0.2958 nm, εH/kB = 36.7 K).7 CO2, N2 were
described by the TraPPE potential (σC = 0.305 nm, εC/kB = 79.0 K, σO = 0.280 nm, εN/kB = 27
K).8 All the potential parameters have been successfully employed to describe the adsorption
of alkanes in zeolites quantitatively. The LJ parameters for the C, H and N atoms from the
frameworks were taken from the DREIDING force field,9 and Co atom was taken from the
all-atom UFF force field,10
which is missed in DREIDING force field. The atoms of the
frameworks were held fixed at their crystallographic coordinates. The excess adsorption
values were conversed from absolute adsorption values, the outputs of GCMC simulations, by
the method of Myers et. al.11
Isosteric heat of adsorption is another interest in our research,
which was obtained from the fluctuation theory.12
While in the limit of zero converge, Qst
was derived from the (NVT) MC calculations.13
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Scheme 1. Model systems used in the ChelpG charge calculations. The atom labels used in
Table S2 are included in the figure.
Table S2. ChelpG charges calculation for 1′, 3' and 4'
1′ 3' 4'
Atom label q/e Atom label q/e Atom label q/e
Zn1 0.864 Co1 0.864 Co1 0.834
C1 0.142 C1 0.119 C1 0.147
C2 -0.193 C2 -0.193 C2 -0.171
C3 0.119 C3 0.142 C3 0.101
C4 -0.183 C4 -0.187 C4 -0.19
C5 0.135 C5 0.135 C5 0.115
C6 -0.187 C6 -0.183 C6 -0.205
C7 0.134 C7 0.145 C7 0.215
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C8 -0.023 C8 -0.008 C8 0.005
C9 0.185 C9 0.265 C9 0.308
C10 0.205 C10 0.134 C10 0.106
C11 0.041 C11 -0.023 C11 -0.002
C12 0.269 C12 0.185 C12 0.165
C13 0.145 C13 0.205 C13 0.169
C14 -0.008 C14 0.041 C14 0.015
C15 0.255 C15 0.259 C15 0.252
H 0.349 H 0.349 H 0.368
H2 0.106 H2 0.106 H2 0.097
H4 0.046 H4 0.1 H4 0.143
H6 0.1 H6 0.046 H6 0.037
H8 0.101 H8 0.098 H8 0.142
H9 0.066 H9 0.095 H9 0.144
H11 0.162 H11 0.101 H11 0.116
H12 0.149 H12 0.066 H12 0.085
H14 0.098 H14 0.162 H14 0.11
H15 0.095 H15 0.149 H15 0.091
N1 -0.471 N1 -0.532 N1 -0.498
N2 -0.536 N2 -0.545 N2 -0.603
N3 -0.545 N3 -0.536 N3 -0.529
N4 -0.532 N4 -0.471 N4 -0.463
N5 -0.594 N5 -0.494 N5 -0.544
N6 -0.494 N6 -0.594 N6 -0.56
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Table S3. Adsorption enthalpies of gases simulated by GCMC calculation
Adsorbent adsorbate Qst (kJ/mol) (sim/exp)
1′
Methane 17.43
H2 7.80/ 7.32
N2 14.51
CO2 32.69/ 33.63
3'
Methane 16.16
H2 7.59/ 7.27
N2 14.60
CO2 32.17/ 33.22
4'
Methane 4.31
H2 3.62
N2 8.38
CO2 22.86
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Figure S1. The coordination environment of Zn(II) atom with thermal ellipsoids at 30%
probability for 1. The free water molecules and hydrogen atoms were omitted for clarity.
Figure S2. a) The 1D helical channel formed by the coordination of Zn(II) and two imidazolyl
groups. b) The 3D porous framework constructed from the connection of imidazolyl group
with adjacent opposite 1D helical channels.
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Figure S3. Schematic representations of the (4, 4)-connected ecl framework of 1 with (4·63·8
2)
topology; turquiose balls represent the Zn(II) atoms, and red balls represent the centers of
benzene rings of H3L ligands.
Figure S4. The coordination environment of Cd(II) atom with thermal ellipsoids at 30%
probability for 2. The free water molecules, perchlorate ions and hydrogen atoms were
omitted for clarity.
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Figure S5. Schematic representations of the (3, 6)-connected pyr framework of 2 with
(63)2(6
12·8
3) topology; green balls represent the Cd(II) atoms, and yellow balls represent the
centers of benzene rings of H3L ligands.
0 100 200 300 400 500 600 700
20
40
60
80
100
Weig
ht
(%)
Temperature (°C)
Figure S6. The TGA curve of complex 1.
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10 20 30 40 50
c
b
2 theta (degree)
a
Figure S7. The X-ray powder diffractions of complex 1: a - simulated; b - as-synthesized; c
- activated.
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Calculation of CO2/N2 selectivity
The methods are applied to estimate the CO2/N2 selectivity according to the literature (J. Am.
Chem. Soc., 2010, 132, 38). The ratios of these initial slopes of the CO2 and N2 adsorption
isotherms were applied to estimate the adsorption selectivity for CO2 over N2.
0 2 4 6 8 10 12 14 16 18 20
0.0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16 18 20
0.0
0.1
0.2
0.3
0.4
0.5
y = 0.09869x +0.01055
R = 0.99972
y = 0.00222x - 0.00357
R = 0.9995
Ga
s U
pta
ke (
mm
ol/
g)
Pressure (KPa)
Figure S8. The fitting initial slope for CO2 and N2 isotherms collected at 273K (CO2:
red squares; N2: green triangles).
0.0 0.2 0.4 0.6 0.8 1.0
0
20
40
60
80
100
120
P/P0
Va
ds/
cm
3g
-1(S
TP
)
1' exp
1' sim
3' exp
3' sim
4' exp
4' sim
Figure S9. Experimental and simulated hydrogen adsorption isotherm at 77 K
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0.0 0.2 0.4 0.6 0.8 1.0
-20
0
20
40
60
80
100
120
140
160
180
P/P0
Va
ds/
cm
3g
-1(S
TP
)
1' exp
1' sim
3' exp
3' sim
4' exp
4' sim
Figure S10. Experimental and simulated CO2 adsorption isotherm at 195 K
0.0 0.2 0.4 0.6 0.8 1.0
0
20
40
60
80
100
120
140
160
Va
ds/
cm
3g
-1(S
TP
)
P/P0
1' exp
1' sim
3' exp
3' sim
4' exp
4' sim
Figure S11. Experimental and simulated N2 adsorption isotherm at 195 K.
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0.0 0.2 0.4 0.6 0.8 1.0
0
20
40
60
80
100
120
Va
ds/
cm
3g
-1(S
TP
)
P/P0
1' exp
1' sim
3' exp
3' sim
4' exp
4' sim
Figure S12. Experimental and simulated CH4 adsorption isotherm at 195 K
0 1 2 3 4 5 6-3
-2
-1
0
1
2
3
4
5
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.02
3
4
5
6
7
8
9
10
77 K
87 K
y=ln(x)+1/T*(a0+a
1*x+a
2*x
2)+(b
0)
R^2 = 0.99968
a0 -876.36592 ? 1.39133
a1 44.72317 ? .64729
a2 2.52633 ? .31029
b0 10.46489 ? .13916
n / mmol g-1
ln(p
/ k
Pa
)
uptake (mmol/g)
Iso
ste
ric
He
at
of
Ad
so
rpti
on
(k
J/m
ol)
Figure S13. H2 isotherm for 1′ with fitting by virial method. (inlet. Isosteric heat of adsorption
with mount of adsorbed H2)
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0 1 2 3 4 5 6-3
-2
-1
0
1
2
3
4
5
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.02
3
4
5
6
7
8
9
10
77 K
87 K
y=ln(x)+1/T*(a0+a
1*x+a
2*x
2)+(b0)
R^2 = 0.99968
a0 -876.36592 ±11.39133
a1 44.72317 ±1.64729
a2 2.52633 ±0.31029
b0 10.46489 ±0.13916
n / mmol g-1
ln(p
/ k
Pa
)
uptake (mmol/g)
Iso
ste
ric
He
at
of
Ad
so
rpti
on
(k
J/m
ol)
Figure S14. H2 isotherm for 3' with fitting by virial method. (inlet. Isosteric heat of adsorption
with mount of adsorbed H2.)
0.0 0.5 1.0 1.5 2.0-6
-4
-2
0
2
4
6
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.010
15
20
25
30
35
40
45
50
273 K
298 K
n / mmol g-1
ln(p
/ k
Pa
)
y=ln(x)+1/T*(a0+a
1*x+a
2*x
2)+(b0)
R^2 = 0.9983
a0 -4054.25515 ±3.72486
a1 169.40076 ±5.05419
a2 59.38549 ±.67006
b0 16.76954 ±.22756
uptake (mmol/g)
Iso
ste
ric
He
at
of
Ad
so
rpti
on
(k
J/m
ol)
Figure S15. CO2 isotherm for 1′ with fitting by virial method.(inlet. Isosteric heat of
adsorption with mount of adsorbed CO2.)
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0.0 0.5 1.0 1.5 2.0 2.5-6
-4
-2
0
2
4
6
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.010
15
20
25
30
35
40
45
50
ln(p
/ k
Pa
)
n / mmol g-1
y=ln(x)+1/T*(a0+a
1*x+a
2*x
2)+(b0)
R^2 = 0.99936
a0 -4000.14059 ±38.83034
a1 78.04655 ±8.14792
a2 73.27012 ±3.55494
b0 16.45262 ±0.1387
273 K
298 K
uptake (mmol/g)
Iso
ste
ric
He
at
of
Ad
so
rpti
on
(k
J/m
ol)
Figure S16. CO2 isotherm for 3' with fitting by virial method.(inlet. Isosteric heat of
adsorption with mount of adsorbed CO2.)
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2000 1500 1000 500
Wavelength(cm-1
)
2
2A
2C
1618
1485
1271
1128
1092992
949
827758626
Figure S17. IR spectra of 2, exchanged product 2A and 2C (reversed exchanged product from
2A to 2C).
2000 1500 1000 500
Wavelength(cm-1
)
2
2B
2D
1621
1571
13821318
11251096
993
945
827758
647
686
Figure S18. IR spectra of 2, exchanged product 2B and 2D (reversed exchanged product from
2B to 2D).
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2000 1500 1000 500
Wavelength(cm-1
)
2
H3L
1617
14951448
1141
11141089
992949
870831
759
626
Figure S19. IR spectra of 2 and ligand H3L.
10 20 30 40 50
d
c
b
2 theta (degree)
a
Figure S20. The X-ray powder diffractions of complex 2: a - simulated; b - as-synthesized;
and exchanged products: c - the exchanged product 2A; d - the exchanged product 2B.
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2000 1500 1000 500
Wavelength(cm-1
)
2A
2B
2A
1618
1570
1488
1452
1271
11251096
992945
827758 648
1390
Figure S21. IR spectra of 2A, exchanged product 2B and 2A (reversed exchanged product
from 2B to 2A).
2000 1500 1000 500
Wavelength(cm-1
)
2B
2A
2B
1618
1568
14881452
1271
11251094
990948
825 756 649
1382
1318
Figure S22. IR spectra of 2B, exchanged product 2A and 2B (reversed exchanged product
from 2A to 2B).
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Electronic Supplementary Material (ESI) for Dalton TransactionsThis journal is © The Royal Society of Chemistry 2014