A robust doubly interpenetrated metal-organic framework constructed from a novel aromatic tricarboxylate for highly selective separation of small hydrocarbons

Article abstract of DOI:10.1039/c2cc31792c

A microporous metal-organic framework, for the first time, has been developed for highly selective separation of industrially important C ₁, C₂ and C₃ hydrocarbons at room temperature.

Full text of DOI:10.1039/c2cc31792c

View Article Online / Journal Homepage / Table of Contents for this issue
Dynamic Article Links
ChemComm
Cite this: Chem. Commun., 2012, 48, 6493–6495
www.rsc.org/chemcomm
COMMUNICATION
A robust doubly interpenetrated metal–organic framework constructed
from a novel aromatic tricarboxylate for highly selective separation of
small hydrocarbonsw
Yabing He,* Zhangjing Zhang, Shengchang Xiang, Frank R. Fronczek,c
a
ab
ab
d
a
Rajamani Krishna* and Banglin Chen*
Received 10th March 2012, Accepted 8th May 2012
DOI: 10.1039/c2cc31792c
A microporous metal–organic framework, for the first time, has
been developed for highly selective separation of industrially
1 2 3
important C , C and C hydrocarbons at room temperature.
The research of new materials for highly selective gas separation
is of significant importance for development of more efficient and
economical ways to purify industrially important gases. As an
emerging class of porous materials, metal–organic frameworks
(
1
MOFs) have recently shown great promise in this aspect. This
Scheme 1 Molecular structures of the organic linkers
BTB, H BBC, and H BTN.
3
H BTC,
is mainly because the micropores within MOFs can be system-
atically tuned by selecting the diverse metal-containing secondary
H
3
3
3
2
building units (SBUs) and the rich organic linkers and/or by
1
excellent gas storage capacity. In light of these observations,
0
3
making use of the framework interpenetration. Furthermore,
we have designed and prepared a much aromatic-richer analogue
0 00 0 00
3
H BTN (6,6 ,6 -benzene-1,3,5-triyl-2,2 ,2 -trinaphthoic acid,
the separation selectivity can be improved by immobilization of
different recognition sites on pore surfaces such as open metal
sites, organic functional groups to direct their different recogni-
Scheme 1) and constructed a microporous MOF (which we
term UTSA-35, UTSA = University of Texas at San Antonio)
with double framework interpenetration. The desolvated frame-
work UTSA-35a exhibits highly selective separation of indust-
rially important small hydrocarbons at room temperature.
4–6
tion for gas molecules.
During the course of MOF development, the use of
C -symmetric tritopic carboxylate linkers turns out to be very
3
7–10
useful in constructing porous MOF materials.
For instance, the
benchmark MOF HKUST-1 is built from the smallest aromatic
3
The organic linker H BTN was readily synthesized by
Pd-catalyzed Suzuki cross-coupling between methyl 6-(pinacol-
boryl)-2-naphthoate and 1,3,5-tribromobenzene followed by
base-catalyzed hydrolysis (see ESIw). UTSA-35 was obtained
as yellowish block-shaped crystals via a solvothermal reaction
tricarboxylates H BTC (benzene-1,3,5-tricarboxylic acid) and the
3
Cu
2 4
(COO) clusters, showing the interesting diverse properties for
9
gas storage/separation, catalysis and proton conductivity.
0
00
Incorporation of the elongated versions H BTB (4,4 ,4 -benzene-
3
0
0
00
of H BTN and Cd(NO ) ꢀ4H O in N,N -dimethylformamide
1,3,5-triyl-tribenzoic acid), H BBC (4,4 ,4 -(benzene-1,3,5-triyl-
3
3
3 2
2
(
DMF) at 100 1C for 24 h. The structure was determined by
4 6
tris(benzene-4,1-diyl))tribenzoic acid) with the Zn O(COO) clusters
single-crystal X-ray diffraction analysis, and the phase purity
of the bulk material was confirmed by powder X-ray diffrac-
tion (PXRD, Fig. S1, ESIw). UTSA-35 can be formulated as
produces MOF-177 and MOF-200, respectively, which exhibit
a
Department of Chemistry, University of Texas at San Antonio,
One UTSA Circle, San Antonio, Texas 78249-0698, USA.
E-mail: Yabing.He@utsa.edu, Banglin.Chen@utsa.edu;
Fax: +1-210-458-7428
Cd
diffraction structure determination, thermogravimetric analysis
TGA), and microanalysis. TGA shows that UTSA-35 can be
thermally stable up to 360 1C under a nitrogen atmosphere
3 2 2 3 6
(BTN) (H O) (DMF) on the basis of single-crystal X-ray
b
(
College of Chemistry and Materials, Fujian Normal University,
3
Shangsan Road, Cangshang Region, Fuzhou, China 350007
c
Department of Chemistry, Louisiana State University, Baton Rouge,
LA 70803-1804, USA
Van ’t Hoff Institute of Molecular Science,
(
Fig. S2, ESIw).
X-ray crystallography reveals that UTSA-35 possesses a
d
University of Amsterdam, Science Park 904, 1098 XH Amsterdam,
The Netherlands. E-mail: r.krishna@uva.nl
two-fold interpenetrated three–dimensional (3D) network that
crystallizes in the monoclinic P2
1
/c space group.z The asymmetric
w Electronic supplementary information (ESI) available: Synthesis
and characterization of H BTN and UTSA-35, PXRD, TGA, sorption
unit contains three Cd centers, two deprotonated ligands,
three coordinated water molecules, one terminal DMF and
five free DMF molecules. Three carboxylate groups of the
3
isotherms, FTIR. CCDC 868753. For ESI and crystallographic data in
CIF or other electronic format see DOI: 10.1039/c2cc31792c
This journal is c The Royal Society of Chemistry 2012
Chem. Commun., 2012, 48, 6493–6495 6493

View Article Online
Fig. 2 Single-component sorption isotherms for various hydrocarbons
in UTSA-35a at 296 K.
As shown in Fig. 2, UTSA-35a takes up different amounts of
ꢂ1
Fig. 1 Single-crystal X-ray structure of UTSA-35 indicating the
trinuclear cadmium–carboxylate secondary building unit (a) linked by
six organic ligands (b), the single net (c) and two-fold interpenetrated
net (d) showing the channel along a axis, and (3,6)-connected topology
ꢂ1
ꢂ1
C
3
H
8
(130.8 mg g ), C
ꢂ1
3
H
6
(138.5 mg g ), C
ꢂ1
2
H
6
(73.0 mg g ),
(6.9 mg g ) at
ꢂ1
C
2
H
4
(60.6 mg g ), C
2
H
2
(75.6 mg g ) and CH
4
2
96 K and 1 atm. The most striking feature is that UTSA-35a
1
2
2 10 3
exhibits adsorption capacity in the following trend: C > C > C ,
1
3
2
¨
2
with Schlafli symbol of (4 6 ) (4 6 8 ) (e). Hydrogen atoms are omitted
highlighting UTSA-35a as a promising material not only for
separation of higher hydrocarbons from CH4 but also for
selective fractionation of these small hydrocarbons according
to the number of carbon atoms.
for clarity.
organic linker adopt different coordination modes: chelating
2
2
1
1
1
(
2 2
Z ), bridging (m –Z :Z ) and chelating–bridging (m –Z :Z ),
respectively (Fig. S3, ESIw). The secondary building unit (SBU) is
a tricadmium–carboxylate cluster where Cd1, Cd2 and Cd3 atoms
are six-, seven- and six-coordinated, respectively (Fig. 1a and b).
The adsorption selectivities of different hydrocarbons with
respect to CH in an equimolar 6-component mixture were
calculated using ideal solution adsorbed theory (IAST) of Myers
4
1
2
2 10 3
11
and Prausnitz. The accuracy of IAST for prediction of gas
The overall topology is a (3,6)-connected binodal (4 6 ) (4 6 8 )
2
net if the organic linker and the metal-containing cluster are taken
as 3-connected and 6-connected nodes, respectively (Fig. 1e).
There exist hexagonal channels in the single net along the
mixture adsorption in many zeolites and MOF materials has
12
been established in a number of publications in the literature.
As shown in Fig. 3, the selectivities of C and C components
with respect to CH are in excess of 80 and 8, respectively, for
3
2
˚
a direction with the approximate dimensions of 11 A (Fig. 1c).
4
Due to the large void, two such nets interpenetrate each other
via intermolecular pꢀ ꢀ ꢀp interactions between the central ben-
zene rings (Fig. 1d). As a result, the stability of the whole
structure is enhanced and the porosity of the framework is
further tuned. The hexagonal channels are dissected into
a range of pressures of up to 100 kPa. Fractionation of these
hydrocarbons is expected to be practically feasible.
To further demonstrate the feasibility, the breakthrough
experiments were simulated using the established methodology
1
3
described in the work of Krishna and Long. Assuming the
isotherm condition, with the adsorber maintained at 296 K,
˚
smaller tetragonal channels with the dimensions of 7.7 ꢁ 5.8 A,
taking into account the van der Waals radii. The void space
accounts approximately 45.8% of the whole crystal volume as
estimated by PLATON.
To characterize the permanent porosity, nitrogen and hydrogen
adsorption experiments were performed at 77 K. The fresh
sample was guest-exchanged with dry acetone and then outgassed
under high vacuum at 333 K to generate desolvated UTSA-35a.
The PXRD pattern of UTSA-35a is similar to that of the pristine
sample (Fig. S1, ESIw), indicating that the framework is main-
2
tained after the removal of the solvent molecules. The N sorption
isotherm at 77 K displays a type I reversible sorption behavior
typical for microporous materials with Brunauer–Emmett–Teller
2
BET) and Langmuir surface areas of 742.7 and 758.4 m g
ꢂ1
(
,
respectively, and a pore volume of 0.313 cm g (Fig. S4 and S5,
3
ꢂ1
ESIw). The hydrogen isotherm at 77 K shows that UTSA-35a
takes up 1.1 wt% H at 1 atm (Fig. S6, ESIw).
2
Establishment of permanent microporosity encourages us to
examine its utility as an adsorbent for industrially important small
hydrocarbon separation. The pure component sorption isotherms
for various hydrocarbons were measured (Fig. S7, ESIw).
Fig. 3 IAST calculations of adsorption selectivities of different hydro-
carbons with respect to CH in an equimolar 6-component mixture at
4
296 K in UTSA-35a.
6
494 Chem. Commun., 2012, 48, 6493–6495
This journal is c The Royal Society of Chemistry 2012

View Article Online
Angew. Chem., Int. Ed., 2004, 43, 2334; (f) H.-L. Jiang and Q. Xu,
Chem. Commun., 2011, 47, 3351; (g) B. Chen, S. Xiang and
G. Qian, Acc. Chem. Res., 2010, 43, 1115; (h) Z. Zhang, S. Xiang
and B. Chen, CrystEngComm, 2011, 13, 5983.
2
3
M. Eddaoudi, J. Kim, N. Rosi, D. Vodak, J. Wachter, M. O’Keeffe
and O. M. Yaghi, Science, 2002, 295, 469.
(a) B. Chen, C. Liang, J. Yang, D. S. Contreras, Y. L. Clancy,
E. B. Lobkovsky, O. M. Yaghi and S. Dai, Angew. Chem., Int. Ed.,
2
006, 45, 1390; (b) B. Chen, S. Ma, F. Zapata, F. R. Fronczek,
E. B. Lobkovsky and H.-C. Zhou, Inorg. Chem., 2007, 46, 1233.
(a) Y.-S. Bae, O. K. Farha, A. M. Spokoyny, C. A. Mirkin,
J. T. Hupp and R. Q. Snurr, Chem. Commun., 2008, 4135;
4
(
b) R. Vaidhyanathan, S. S. Iremonger, G. K. H. Shimizu,
P. G. Boyd, S. Alavi and T. K. Woo, Science, 2010, 330, 650;
c) J. An, S. J. Geib and N. L. Rosi, J. Am. Chem. Soc., 2010,
32, 38; (d) T. Panda, P. Pachfule, Y. Chen, J. Jiang and
(
1
R. Banerjee, Chem. Commun., 2011, 47, 2011; (e) J.-P. Zhang
and X.-M. Chen, J. Am. Chem. Soc., 2009, 131, 5516; (f) Q. Lin,
T. Wu, S.-T. Zheng, X. Bu and P. Feng, J. Am. Chem. Soc., 2012,
134, 784; (g) Y.-X. Tan, Y.-P. He and J. Zhang, Chem. Commun.,
2011, 47, 10647; (h) Z. Chen, S. Xiang, H. D. Arman,
J. U. Mondal, P. Li, D. Zhao and B. Chen, Inorg. Chem., 2011,
Fig. 4 The simulated transient breakthrough of an equimolar
–component mixture containing C , C , C , C , C
and CH in an adsorber packed with UTSA-35a, operating under
6
3
H
8
3
H
6
2
H
6
2
H
4
2 2
H ,
4
isothermal conditions at 296 K. The inlet gas is maintained at partial
5
0, 3442.
pressures Pi0 = 16.67 kPa.
5
6
D. Britt, H. Furukawa, B. Wang, T. G. Glover and O. M. Yaghi,
Proc. Natl. Acad. Sci. U. S. A., 2009, 106, 20637.
Y.-S. Bae, C. Y. Lee, K. C. Kim, O. K. Farha, P. Nickias,
J. T. Hupp, S. T. Nguyen and R. Q. Snurr, Angew. Chem., Int. Ed.,
2012, 51, 1857.
(a) B. Chen, M. Eddaoudi, S. T. Hyde, M. O’Keeffe and
O. M. Yaghi, Science, 2001, 291, 1021; (b) K. Koh, A. G. Wong-
Foy and A. J. Matzger, Angew. Chem., Int. Ed., 2008, 47, 677;
(c) K. Gedrich, I. Senkovska, N. Klein, U. Stoeck, A. Henschel,
M. R. Lohe, I. A. Baburin, U. Mueller and S. Kaskel, Angew.
Chem., Int. Ed., 2010, 49, 8489; (d) S.-T. Zheng, J. J. Bu, T. Wu,
C. Chou, P. Feng and X. Bu, Angew. Chem., Int. Ed., 2011,
the transient breakthrough of an equimolar 6-component mixture
containing CH , C H , C H , C H , C H and C H was deter-
4
2
2
2
4
2
6
3
6
3
8
mined. The molar concentrations of the gas phase exiting the
adsorber are shown in Fig. 4 for a gas mixture with partial
pressures of 16.67 kPa each for each of the six components in
7
the inlet. From the breakthrough curves, we note that CH
component with the poorest adsorption strength, breaks through
earliest, followed by the C components with the moderate
adsorption strength and finally by C components with the
4
, the
2
3
5
0, 8858.
8 (a) S. Ma and H.-C. Zhou, J. Am. Chem. Soc., 2006, 128,
1734–11735; (b) Y. K. Park, S. B. Choi, H. Kim, K. Kim,
strongest adsorption strength. Therefore it is possible to frac-
tionate the mixture into three separate streams: CH , C hydro-
carbons and C hydrocarbons during the adsorption cycle.
1
4
2
B.-H. Won, K. Choi, J.-S. Choi, W.-S. Ahn, N. Won, S. Kim,
D. H. Jung, S.-H. Choi, G.-H. Kim, S.-S. Cha, Y. H. Jhon,
J. K. Yang and J. Kim, Angew. Chem., Int. Ed., 2007, 46, 8230.
9 (a) S. S.-Y. Chui, S. M.-F. Lo, J. P. H. Charmant, A. G. Orpen and
I. D. Williams, Science, 1999, 283, 1148; (b) B. Xiao,
P. S. Wheatley, X. Zhao, A. J. Fletcher, S. Fox, A. G. Rossi,
I. L. Megson, S. Bordiga, L. Regli, K. M. Thomas and
R. E. Morris, J. Am. Chem. Soc., 2007, 129, 1203; (c) S. Xiang,
W. Zhou, J. M. Gallegos, Y. Liu and B. Chen, J. Am. Chem. Soc.,
3
In summary, we design a novel expanded and decorated
ligand and synthesize a robust doubly interpenetrated metal–
1 2 3
organic framework for fractionation of C , C and C hydro-
carbons. This is the first example of porous metal–organic
frameworks for such industrially important hydrocarbon
1
4,15
separation.
The interactions between the MOF material
2
009, 131, 12415; (d) C.-Y. Sun, S.-X. Liu, D.-D. Liang,
K.-Z. Shao, Y.-H. Ren and Z.-M. Su, J. Am. Chem. Soc., 2009,
31, 1883; (e) N. C. Jeong, B. Samanta, C. Y. Lee, O. K. Farha and
J. T. Hupp, J. Am. Chem. Soc., 2012, 134, 51.
0 (a) H. K. Chae, D. Y. Siberio-Perez, J. Kim, Y. Go, M. Eddaoudi,
A. J. Matzger, M. O’Keeffe and O. M. Yaghi, Nature, 2004,
27, 523; (b) H. Furukawa, N. Ko, Y. B. Go, N. Aratani,
S. B. Choi, E. Choi, A. O. Yazaydin, R. Q. Snurr, M. O’Keeffe,
and hydrocarbons are mainly van der Waals interactions
which favor the stronger adsorption of higher hydrocarbons.
The size-selective effect plays an important role in the separation
of C H /C H and C H /C H . It is expected that this work will
1
1
´
2
2
2
4
2
2
2
6
stimulate more investigation of newly emerging microporous
metal–organic frameworks for separation of industrially impor-
tant small hydrocarbons and eventually some practically useful
MOF materials will be targeted in the future.
4
¨
J. Kim and O. M. Yaghi, Science, 2010, 329, 424.
1 A. L. Myers and J. M. Prausnitz, AIChE J., 1965, 11, 121.
2 (a) R. Krishna, S. Calero and B. Smit, Chem. Eng. J., 2002, 88, 81;
1
1
This work was supported by an AX-1730 from Welch
Foundation (BC).
(
b) R. Krishna and J. M. van. Baten, Chem. Eng. J., 2007, 133, 121;
(c) R. Krishna and J. M. van. Baten, Phys. Chem. Chem. Phys.,
011, 13, 10593; (d) R. Krishna and J. M. van. Baten, J. Membr.
2
Sci., 2011, 377, 249.
Notes and references
1
3 R. Krishna and J. R. Long, J. Phys. Chem. C, 2011, 115, 12941.
4 (a) M. C. Das, H. Xu, S. Xiang, Z. Zhang, H. D. Arman, G. Qian
and B. Chen, Chem.–Eur. J., 2011, 17, 7817; (b) S. Xiang,
Z. Zhang, C.-G. Zhao, K. Hong, X. Zhao, D.-L. Ding,
M.-H. Xie, C.-D. Wu, R. Gill, K. M. Thomas and B. Chen, Nat.
Commun., 2011, 2, 204; (c) Y. He, S. Xiang and B. Chen, J. Am.
Chem. Soc., 2011, 133, 14570; (d) Y. He, Z. Zhang, S. Xiang,
F. R. Fronczek, R. Krishna and B. Chen, Chem.–Eur. J., 2012,
18, 613; (e) Y. He, Z. Zhang, S. Xiang, H. Wu, F. R. Fronczek,
W. Zhou, R. Krishna, M. O’Keeffe and B. Chen, Chem.–Eur. J.,
2012, 18, 1901.
1
z Crystal data for UTSA-35: C96
3 6
H90Cd N O21, M = 2001.00, mono-
˚
˚
clinic, space group P2 /c, a = 14.306(2) A, b = 19.509(3) A, c =
1
3
ꢂ3
,
˚
˚
3
6.482(5) A, b = 99.6290(9)1, V = 10039(2) A , Z = 4, D
c
= 1.324 g cm
= 0.0594 for
= 0.1744 for all data, GoF = 1.022, CCDC 868753.
ꢂ1
m(Mo-K
I > 2s(I), wR
a
) = 0.683 mm , F(000) = 3440, final R
1
2
1
(a) J.-R. Li, J. Sculley and H.-C. Zhou, Chem. Rev., 2012, 112, 869;
b) K. Sumida, D. L. Rogow, J. A. Mason, T. M. McDonald,
E. D. Bloch, Z. R. Herm, T.-H. Bae and J. R. Long, Chem. Rev.,
(
2
012, 112, 724; (c) Y.-S. Bae and R. Q. Snurr, Angew. Chem., Int. Ed.,
011, 50, 11586; (d) H. Wu, Q. Gong, D. H. Olson and J. Li, Chem.
2
Rev., 2012, 112, 836; (e) S. Kitagawa, R. Kitaura and S.-I. Noro,
15 E. D. Bloch, W. L. Queen, R. Krishna, J. M. Zadrozny,
C. M. Brown and J. R. Long, Science, 2012, 335, 1606.
This journal is c The Royal Society of Chemistry 2012
Chem. Commun., 2012, 48, 6493–6495 6495