Relation Between Coordination and Lewis‐Acid Property of MOF‐Derived Mononuclear Zn(II) Catalyst Toward Epoxide Hydroxylation

Abstract

AbstractLewis‐acid properties of the coordinatively unsaturated metal ions are highly relevant to the coordination environment; however, it remains a challenge to establish the coordination structure‐activity relationship, especially in heterogeneous catalysis. Here, a typical metal‐organic framework, ZIF‐8, is selected as the precursor to prepare Lewis‐acid based Zn−N/P−C mononuclear catalysts, with well‐designed external structures but difference in the local coordination. The obtained mononuclear Zn(II) catalysts can not only inherit the advantages of MOF in coordination, but also simulate the homogeneous environment during the catalysis owing to the monodispersed metal sites in ZIF‐8. Eventually, relation between coordination and Lewis‐acid property toward epoxide hydroxylation has been illustrated. Results show the substituted coordination atom of P and the decrease of coordination number strongly enhance the Lewis‐acidity of Zn2+, causing the TOF values changes from 8.7 to 80.1 h−1 based on Zn content. The work affords an understanding and inspiration of coordination environment matters toward Lewis‐acid catalysis in organic transformations.