Partial Linker Substitution Strategy to Construct a Quaternary HKUST-like MOF for Efficient Acetylene Storage and Separation.

Multicomponent metal-organic frameworks (MOFs) have received much attention as emerging materials capable of precisely programing exquisite structures and specific functions. Here, we applied a partial linker substitution strategy to compile an HKUST-1-like quaternary MOF by introducing a bifunctional ligand into the well-known HKUST-1 structure. FUT-1, a new HKUST-like tbo topology MOF, was assembled with paddlewheel [Cu2(COO)4], triangular metallocycle pyrazole cluster Cu3(μ3-OH) (NN)3 building blocks, and two distinct linkers. FUT-1 exhibited good mechanical stability, water stability, and chemical stability (pH = 3-12) in aqueous solutions. Moreover, the porous environments created by this multicomponent primitive endow FUT-1 with high C2H2 storage and significantly selective separation performance of C2H2/CO2. Dynamic breakthrough experiments and ideal adsorbed solution theory calculations further demonstrate that FUT-1 can selectively capture C2H2 from C2H2/CO2 mixtures under ambient conditions. Based on grand canonical Monte Carlo simulations, the high C2H2 separation performance of FUT-1 is attributed to the π-complex formed between the C2H2 molecule and the trinuclear metallocycle clusters on the wall, which provides stronger affinity for C2H2 recognition than the CO2 molecule.