Inorganic Chemistry
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carbonates under ambient conditions (at room temperature
under 1 atm of pressure).11 MMPF-18 displays great catalytic
efficiency for CO2 coupled with propylene oxide forming
propylene carbonate under ambient conditions with a yield of
96.97% (Table 1, entry 1) over 48 h. MMPF-18 dramatically
from phenyl glycidyl ether. Compared to a homogeneous Zn-
TPP catalyst with a 44.20% yield of phenyl glycidyl carbonate
(Table 1, entry 8), the lower yield of MMPF-18 could be
ascribed to not only the intrinsic activity of the substrate but
also the limited diffusion of the large substrate into the narrow
channels of MMPF-18, hence displaying size-selective catal-
ysis.12
Table 1. Cycloaddition Reactions Promoted by Different
Catalysts from Different Substituted Epoxides and CO2
CONCLUSIONS
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In summary, a robust pcu-topology MMPF, MMPF-18, was
built from a linear free-base porphyrin that connects the
prototypal SBU of Zn4(μ4-O)(−COO)6. Strong π−π stacking
from porphyrins and the lengthy H2bcpp ligand offers a 4-fold-
interpenetrating network along with reduced void spaces and
confined narrow channels. Meanwhile, the porphyrin cores
were in situ metalated under solvothermal reaction conditions.
Thus, MMPF-18 presents the limited pore size and high-
density metalloporphyrin centers enabled by interpenetration
for selective CO2 uptake over CH4 and size-selective chemical
transformation of CO2 with epoxides into cyclic carbonates
under ambient conditions, although its chemical stability needs
to be boosted in terms of long-term application.13 It can be
further anticipated that interpenetration can be considered an
effective means to not only enhance the stability of MOF
structures but also render pore sizes and functionalities for size-
selective separation and heterogeneous catalysis.
ASSOCIATED CONTENT
* Supporting Information
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S
The Supporting Information is available free of charge on the
a
Reaction conditions: epoxide (10.0 mmol), n-Bu4NBr (232.0 mg),
Details of experiments and characterizations (PDF)
X-ray crystallographic data in CIF format (CIF)
and MMPF-18 (17.6 mg, 0.25 mol % based on metalloporphyrin
core), under 1 atm of CO2 at room temperature for 48 h. The yield
was monitored by H NMR. The same conditions but loaded with
HKUST-1 (0.125 mol % per dicopper-paddlewheel SBUs). The same
conditions but loaded with Zn-TPP (0.25 mol % based on a
metalloporphyrin core).
b
1
c
AUTHOR INFORMATION
Corresponding Author
■
Notes
exceeds the benchmark MOF of HKUST-1 with 49.20% yield
(Table 1, entry 2) under similar reaction conditions, which
features Lewis acid sites from a copper-paddlewheel SBU.
Meanwhile, the catalytic efficiency of MMPF-18 is comparable
to that of a homogeneous zinc tetraphenylporphyrin (Zn-TPP)
catalyst (Table 1, entry 3). The remarkable catalytic efficiency
of MMPF-18 for CO2 chemical transformation should be
attributed to not only strong Lewis acidity from Zn-based
porphyrins, as observed in homogeneous systems, but also
accessible porosities facilitating substrate mass transfer. In order
to generalize the results of this study, we systematically
evaluated the catalytic activity of MMPF-18 in CO2 chemical
transformation with different functional-group-substituted
epoxides under ambient conditions. MMPF-18 also exhibits
high catalytic efficiency for cycloaddition reactions of butylene
oxide, epichlorohydrin, and allyl glycidyl ether using CO2 to
form butylene carbonate (Table 1, entry 4), chloroethylene
carbonate (Table 1, entry 5), and allyl glycidyl carbonate
(Table 1, entry 6) with yields of 96.63%, 99.00%, and 99.60%,
respectively, over 48 h. Furthermore, an impressive decrease in
the yield of cyclic carbonate was observed with an increase of
the molecular size of the epoxide substrate, as illuminated by
the 33.25% yield of phenyl glycidyl carbonate (Table 1, entry 7)
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The National Science Foundation (Grant DMR-1352065) and
University of South Florida are gratefully acknowledged for
financial support. We thank Dr. Tony Pham for his generous
help with IAST calculations.
REFERENCES
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(1) (a) Chu, S. Science 2009, 325, 1599. (b) Li, J.-R.; Ma, Y.;
McCarthy, M. C.; Sculley, J.; Yu, J.; Jeong, H.-K.; Balbuena, P. B.;
Zhou, H.-C. Coord. Chem. Rev. 2011, 255, 1791−1823.
(2) (a) Liu, J.; Thallapally, P. K.; McGrail, B. P.; Brown, D. R.; Liu, J.
Chem. Soc. Rev. 2012, 41, 2308−2322. (b) Sumida, K.; Rogow, D. L.;
Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T.-H.;
Long, J. R. Chem. Rev. 2012, 112, 724−781.
(3) (a) Lanzafame, P.; Centi, G.; Perathoner, S. Chem. Soc. Rev. 2014,
43, 7562−7580. (b) Gao, W.-Y.; Wu, H.; Leng, K.; Sun, Y.; Ma, S.
Angew. Chem., Int. Ed. 2016, 55, 5472−5476.
(4) (a) North, M.; Pasquale, R. Angew. Chem., Int. Ed. 2009, 48,
2946−2948. (b) Luo, R.; Zhou, X.; Chen, S.; Li, Y.; Zhou, L.; Ji, H.
Green Chem. 2014, 16, 1496−1506. (c) Wang, Y.; Qin, Y.; Wang, X.;
Wang, F. Catal. Sci. Technol. 2014, 4, 3964−3972.
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