A new threefold interpenetrated pillared-layer microporous metal-organic framework, [Zn2 (cca)2 (4-bpdb)]n ⋅(DMF)2n (UTSA-85) (H2 cca=4-carboxycinnamic acid, 4-bpdb=1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, and DMF=N,N-dimethylformamide), has been designed and generated by the solvothermal reaction of mixed ligands (H2 cca and 4-bpdb) and Zn(NO3 )2 ⋅6 H2 O. Single-crystal XRD analysis disclosed that discrete paddle-wheel Zn2 (COO)4 clusters as secondary building units linked the cca ligands to give two-dimensional layers, which were further pillared by 4-bpdb ligands to form a threefold interpenetrated pillared-layer structure. The desolvated framework, UTSA-85 a, was revealed to exhibit permanent porosity with a BET surface area of 558 m2 g-1 and a high selectivity of 64 for C2 H2 /CH4 separation at 296 K owing to the microporous (≈5.0 Å) structure and functional azine groups that decorated the pore channels.
Keywords: cluster compounds; gas separation; metal-organic frameworks; microporous materials; zinc.
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