Trinuclear Co(II)-Based Metal-Organic Framework as a Heterogeneous Catalyst for the Ring-Opening Reaction of Epoxides

The ring-opening of epoxides plays a crucial role in synthesizing antitumoral pharmaceuticals and fine chemicals, and the key lies in the rational design of highly efficient catalysts. Herein, by using 4-(2-carboxyethenyl)benzoic acid and 1,10-phenanthroline (phen) hydrate as mixed ligands, a new Co(II)-based porous metal-organic framework (Co-CBA) has been synthesized via a solvothermal reaction. Structural analysis revealed that Co-CBA features unique trinuclear clusters as building blocks, which link with the ligands to form a sequentially porous two-dimensional network. The appropriate pore channels and high density of metal active clusters in Co-CBA facilitate its exceptional catalytic performance as a heterogeneous catalyst in the ring-opening reaction of epoxy chloropropane with methanol. Under optimal conditions, this catalyst achieves >99% conversion and >99% selectivity for the target product 1-chloro-3-methoxypropan-2-ol within 28 h. In addition, Co-CBA also displays excellent substrate compatibility, outstanding reusability, and robust structural stability after the catalysis. A plausible reaction pathway for the ring-opening of epoxides has also been proposed.