Additive-Induced Supramolecular Isomerism and Enhancement of Robustness in Co(II)-Based MOFs for Efficiently Trapping Acetylene from Acetylene-Containing Mixtures

Although
supramolecular isomerism in metal–organic frameworks
(MOFs) would offer a favorable platform for in-depth exploring their
structure–property relationship, the design and synthesis of
the isomers are still rather a challenging aspect of crystal engineering.
Here, a pair of supramolecular isomers of Co­(II)-based MOFs (FJU-88 and FJU-89) can be directionally fabricated
by rational tuning the additives. In spite of the fact that the isomers
have the similar Co3 secondary building units and organic
linkers, they adopt distinct networks with acs and snw topologies, respectively, which derive from the conformational
flexibility of the organic ligands. It is noteworthy that the porous
structure of FJU-88 would be collapsed after removal
of the solvent from the pores. But FJU-89a shows permanent
porosity accompanied with unusual hierarchical micro- and mesopores
and superior gas selective adsorption performance. In addition, FJU-89a can efficiently trap C2H2 from
C2H2/CO2 and C2H2/CH4 mixture gases through fixed-bed dynamic breakthrough
experiments.