Synthesis, characterization and catalytic activity of -oxo bridged dinuclear iron 1,10 phenanthroline complex encapsulated in MCM-41

Abstract

This paper describes the encapsulation of -oxo bridged dinuclear iron 1,10 phenanthroline (Fe-phen) complex in MCM-41. These systems have been characterized by thermogravimetric analysis (TGA), UV–Vis, FT-IR, EPR and cyclic voltammetry. On encapsulation reduction potential of Fe-phen is shifted by 275 mV more positive due to perturbation of molecular energy levels. Because of antiferromagnetic coupling a decrease in EPR signal intensity is observed as temperature is lowered from 300 to 77 K. By comparing the performance of the heterogeneous system with the free complex in the oxidation of benzyl alcohol using t-butyl hydroperoxide (TBHP), a protection effect of the matrix over the active center was evidenced by high turnover and yield of product. UV–VIS spectrum shows in neat complex Fe–O–Fe bridge is cleaved during the oxidation of benzyl alcohol while in encapsulated system, it is stable.