Epoxidation of alkenes by an oxidovanadium(IV) tetradentate Schiff base complex as an efficient catalyst with tert-butyl hydroperoxide

Abstract

A new asymmetrical tetradentate N2O2 Schiff base ligand was synthesized from 2-hydroxyacetophenon, 2-hydroxynaphthaldehyde and 1,2 phenylenediimine. The new oxidovanadium(IV) Schiff base complex, VIVOL (L=N-2-hydroxyacetophenon-N′-2-hydroxynaphthaldehyde-1,2 phenylenediimine), was prepared by reaction of Schiff base ligand with vanadyl acetylacetonate. The Schiff base ligand (L) and the oxidovanadium(IV) complex were characterized by spectroscopic methods. The crystal structure of the complex was determined by the single crystal X-ray analysis. The complex crystallized in the orthorhombic system, having one V4+ ion coordinating in an approximately square pyramidal N2O3 geometry by two azomethine N atoms and phenolic oxygens from Schiff base ligand in a square plane and one oxygen atom in an apical position. Electrochemical properties of the complex were examined by means of cyclic voltammetry. The catalytic activity of the oxidovanadium(IV) Schiff base complex was tested in the epoxidation of cyclooctene.