New Doubly Interpenetrated MOF with [Zn₄O] Clusters and Its Doped Isomorphic MOF: Sensing, Dye, and Gas Adsorption Capacity

A doubly interpenetrated metal–organic framework (MOF) [Zn₄(L)₃O]·8DMF·H₂O (1, DMF = N,N-dimethylformamide) including the [Zn₄O] clusters was first synthesized by employing a rigid 2,6-bis­(4′-carboxyl-phenyl)­pyridine (H₂L) ligand. Then, the isomorphic complex 2 was prepared by partially replacing Zn­(II) ions with Co­(II) ions in the structure of 1. The luminescent investigations showed complex 1 is a great MOF-based probe for sensing the environmentally relevant Fe³⁺ and Cu²⁺ ions and nitrobenzene. Meanwhile, complex 1 displayed the unique selective sorption to methylene blue dyes. Notably, the CO₂ sorption demonstrated that complexes 1 and 2 showed the special gate-opening effect at low temperatures. Especially, the gate-opening pressure of the isostructural product can be adjusted by doping Co­(II) ions into the [Zn₄O] clusters. Thereby, complex 1 should be a useful material for sensing, dye, and gas adsorption.