Page 3 of 4
Journal of the American Chemical Society
In summary, we have demonstrated that using ligand exchange, a
1
2
3
4
5
6
7
8
short linker molecule in a MOF can be replaced with a longer one to
produce a more porous isoreticular analogue without sacrificing loss of
crystallinity. This process can be applied sequentially to yield product
MOFs with increasingly larger pore sizes. We predict that this method
can also be used to isolate new MOFs that cannot be prepared using
traditional synthetic methods. We have established herein that, collec-
tively, bio-MOFs 100-103 are one of the most porous families of MOF
materials based on the important metric of total pore volume.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Electronic Supplementary Information (ESI) available: Additional
synthetic procedures, instrumentations, X-ray experiments, 1H-NMR,
etc. This information is available free of charge via the internet at
A portion of this work was performed under the RES contract DE-
FE0004000 as part of the National Energy Technology Laboratory’s
Regional University Alliance (NETL-RUA), a collaborative initiative of
the NETL. The authors also thank the Petersen Institute for Nanosci-
ence and Engineering (PINSE) for access to XRPD instrumentation
and the Mechanical Engineering and Materials Science (MEMS) De-
partment for access to SEM instrumentation.
Figure 4. (A) N2 adsorption isotherms of bio-MOF-101 (navy), bio-
MOF-100 (red), bio-MOF-102 (green), bio-MOF-103 (orange) at 77
K. (B) normalized pore size distribution (PSD) of bio-MOF-101 (na-
vy), bio-MOF-100 (red), bio-MOF-102 (green), bio-MOF-103 (or-
ange) calculated by quenched solid state functional theory (QSDFT)
method.7
(1) (a) Wang, X.-S.; Ma, S.; Sun, D.; Parkin, S.; Zhou, H.-C. J. Am. Chem. Soc.,
2006, 128, 16474. (b) Fang, Q.-R.; Makal, T.; Young, M.; Zhou, H.-C.
Comments Inorg. Chem., 2010, 31, 165. (c) Xuan, W.; Zhu, C.; Liu, Y.; Cui, Y.
Chem. Soc. Rev., 2012, 41, 1677.
(2) (a) An, J.; Farha, O. K.; Hupp, J. T.; Pohl, E.; Yeh, J. I.; Rosi, N. L. Nat.
Common., 2012, 3, 604. (b) Morris, W.; Volosskiy, B.; Demir, S.; Gandara, F.;
McGrier, P. L.; Furukawa, H.; Cascio, D.; Stoddart, J. F.; Yaghi, O. M. Inorg.
Chem., 2012, 51, 6443. (c) Feng, D.; Gu, Z. Y.; Li, J. R.; Jiang, H. L.; Wei, Z.;
Zhou, H. C. Angew. Chem., Int. Ed., 2012, 51, 10307. (d) Chen, Y.; Hoang, T.;
Ma, S. Inorg. Chem., 2012, 51, 12600 (e) Deng, H.; Grunder, S.; Cordova, K.
E.; Valente, C.; Furukawa, H.; Hmadeh, M.; Gandara, F.; Whalley, A. C.; Liu,
Z.; Asahina, S.; Kazumori, H.; O'Keeffe, M.; Terasaki, O.; Stoddart, J. F.; Yaghi,
O. M. Science 2012, 336, 1018.
the bio-MOF-102 product (Figure 3C) was reacted with H2-NH2-
TPDC. The light orange product crystals of bio-MOF-103 (Figure
3D) have a height of 3.1 mm. This continuous change in sample height
offers qualitative visual proof of the volume change of the crystals after
ligand exchange.
The porosities of bio-MOF-101 and the products of ligand ex-
change, bio-MOF-100, 102, and 103, were investigated by N2 gas ad-
sorption at 77 K. Crystalline samples were completely exchanged with
ethanol and activated using established methods.8 Each material exhib-
its a Type IV adsorption isotherm characteristic of mesoporous materi-
als (Figure 4A). The analogue with the shortest linker, bio-MOF-101,
adsorbs the least amount of N2 and has a calculated pore volume of
2.83 cc/g. The bio-MOF-100 sample prepared herein adsorbed 2444
cc/g N2 which is slightly lower than the previously reported value.2a We
surmise that this may be due to defects created during the ligand ex-
change process. As expected, bio-MOF-102 and 103 show the highest
N2 uptakes and exhibit calculated pore volumes of 4.36 cc/g and 4.13
cc/g, respectively. The pore volume of bio-MOF-102 exceeded the
reported pore volume of bio-MOF-100, making it the second most
porous MOF reported in terms of the pore volume metric. We note
that only the isotherm for bio-MOF-103 shows hysteresis upon de-
sorption; we hypothesize that this may be due to the incomplete ex-
change of ABDC by NH2-TPDC (vide supra). We calculated the pore
size distribution for each material using the QSDFT method (Figure
4B).7 These data definitively demonstrate that the ligand exchange
method can be used to systematically increase the pore size of this class
of mesoporous bio-MOFs from ~2.00 nm to 2.84 nm, which agrees
well with the pore sizes predicted from the crystal structures (2.1 nm to
2.9 nm).
(3) Farha, O. K.; Eryazici, I.; Jeong, N. C.; Hauser, B. G.; Wilmer, C. E.;
Sarjeant, A. A.; Snurr, R. Q.; Nguyen, S. T.; Yazaydin, A. O.; Hupp, J. T. J. Am.
Chem. Soc., 2012, 134, 15016.
(4) Liu, C.; Li, T.; Rosi, N. L. J. Am. Chem. Soc., 2012, 134, 18886.
(5) (a) Kondo, M.; Furukawa, S.; Hirai, K.; Kitagawa, S. Angew. Chem., Int.
Ed., 2010, 49, 5327. (b) Park, H. J.; Cheon, Y. E.; Suh, M. P. Chem.--Eur. J.,
2010, 16, 11662. (c) Li, J.-R.; Zhou, H.-C. Nat. Chem., 2010, 2, 893. (d)
Burnett, B. J.; Barron, P. M.; Hu, C.; Choe, W. J. Am. Chem. Soc., 2011, 133,
9984. (e) Burnett, B. J.; Choe, W. Dalton Trans., 2012, 41, 3889. (f) Kim, M.;
Cahill, J. F.; Fei, H.; Prather, K. A.; Cohen, S. M. J. Am. Chem. Soc., 2012, 134,
18082. (g) Cohen, S. M. Chem. Rev., 2012, 112, 970. (h) Park, J.; Wang, Z. U.;
Sun, L. B.; Chen, Y. P.; Zhou, H. C. J. Am. Chem. Soc., 2012, 134, 20110. (i)
Kim, M.; Cahill, J. F.; Su, Y.; Prather, K. A.; Cohen, S. M. Chem. Sci., 2012, 3,
126. (j) Karagiaridi, O.; Bury, W.; Sarjeant, A. A.; Stern, C. L.; Farha, O. K.;
Hupp, J. T. Chem. Sci., 2012, 3, 3256.
(6) Delgado Friedrichs, O.; O'Keeffe, M.; Yaghi, O. M. Acta Crystallogr., Sect.
A, 2003, 59, 515.
(7) Ravikovitch, P. I.; Neimark, A. V. Langmuir 2006, 22, 11171.
(8) Nelson, A. P.; Farha, O. K.; Mulfort, K. L.; Hupp, J. T. J. Am. Chem. Soc.,
2008, 131, 458.
ACS Paragon Plus Environment