2D Co-based coordination polymer with a histidine derivative as an efficient heterogeneous catalyst for the oxidation of cyclohexene

Abstract

The hydrothermal reaction of CoCl₂ and 4-((1-carboxy-2-(1H-imidazol-4-yl)ethylamino)methyl)benzoic acid (H₂L) generated a {Co₂(H₂O)}-based 2D coordination framework, {(Co(L)(H₂O))₂(H₂O)}_n (1). Heterogeneous catalytic experiments on the allylic oxidation of cyclohexene show that activated 1 exhibits high catalytic activity using tert-butylhydroperoxide (t-BuOOH) as the oxidant toward the formation of tert-butyl-2-cyclohexenyl-1-peroxide. The activation energy for the oxidation of cyclohexene with catalyst 1 was approximately calculated as 91.98 kJ mol⁻¹. This work demonstrates that a degree of creativity in the coordinatively unsaturated metal sites in CPs could significantly enhance their heterogeneous catalytic activity and selectivity.