Abstract:
Highly thermal and chemically stable, 20-
connected lanthanide metal−organic frameworks (MOFs)
[{Ln(BTB)(H2O)}·H2O]n (where Ln = Sm (MOF1)/Gd
(MOF2), BTB = 1,3,5-tris (4-carboxy phenyl) benzene) have
been synthesized solvothermally and characterized by singlecrystal X-ray diffraction analysis and other physicochemical
methods. MOF1 and 2 are isostructural and feature threedimensional honeycomb-like structure with large one-dimensional hexagonal channels of dimension ∼10.20 × 10.11 Å2
. Gas uptake studies of the samples revealed selective adsorption
properties of MOF1 for CO2 over other (N2, Ar, and H2) gases. The activated samples of the MOF1/2 act as efficient recyclable
catalysts for heterogeneous cycloaddition of CO2 with styrene oxide, resulting in cyclic carbonate with high yield and selectivity.
Interestingly, the pore size-dependent catalytic conversion of epoxides has been observed, suggesting the potential utility of
MOF1 as a promising heterogeneous catalyst for cycloaddition of carbon dioxide. Furthermore, the MOF1 catalyst can be easily
recycled for several cycles without significant loss of catalytic activity as well as structural rigidity. MOF1 and 2 represent rare
examples of 20-c lanthanide MOFs exhibiting selective capture and efficient cycloaddition of CO2 with epoxides at mild
conditions.
