No abstract

The catalytic epoxidation of styrene using ureahydrogen peroxide and heterotrinuclear Cu(II) complexes with general formula (ML n ) 2 Cu(acac) 2 , where n = 1-3 and M = VO 2? or Mn 2? is reported. Schiff base complexes ML n involving a 3,4-diaminopyridine bridge with free coordination site were used as the ligand, where (L n ) 2-is [(5-x-Sal) 2 Py] 2 and x = H, Br or NO 2 . The complexes were characterized by physico-chemical and spectroscopic methods. The electrochemical properties of M were modified upon trinuclear complex formation. The trinuclear complexes show high catalytic activity, with up to 86% conversion and 93% selectivity, while no catalytic properties were observed for the monomeric complexes. The catalyst could be reused with some loss of activity.