A LADH-like Zn-MOF as an efficient bifunctional catalyst for cyanosilylation of aldehydes and photocatalytic oxidative carbon–carbon coupling reaction

Abstract

The rational design of component and coordination configuration of active center is critical and useful to the development of multifunctional MOF-based catalysts. Herein, a bifunctional Zn-MOF, Zn-ADBA, constructed by photoactive 4,4’-(9,10-anthracenediyl)dibenzoic acid (H2ADBA) ligand and Zn(II) ions, is employed as heterogeneous catalyst for efficient cyanosilylation and photocatalytic oxidative carbon–carbon coupling reactions. The unsaturated Zn(II) centers with strong Lewis acid character can effectively active aldehyde substates, which promotes Zn-ADBA to catalyze cyanosilylation of electron-withdrawing substituted benzaldehyde with a turnover frequency value up to 53.1 h−1. Meanwhile, the photo-functional ADBA2- ligands featuring large steric hindrance drive the Zn(II) center adopt the liver alcohol dehydrogenase (LADH) like characteristics, which renders Zn-ADBA (λmax absorption ​= ​406 ​nm) high-efficient photocatalytic oxidation of N-aryl-tetrahydroisoquinoline substrates with yields above 95% over 4 ​h under visible light. The recyclability of Zn-ADBA and the possible catalytic mechanisms are also systematically investigated by a series of experiments including PXRD, IR, EPR and DFT analyses.