Mn(III) complexes of the monoprotic tridentate ONN donor 2-[2-(1H-(benzo[d]imidazol-2-yl)ethylimino)methyl]phenol as a functional mimic of haloperoxidase

Abstract

The reaction of Mn II(ClO 4) 2 with 2-[2-(1H-(benzo[d]imidazol-2-yl)ethylimino)methyl]phenol (Hsal-aebmz, I) under aerobic conditions results in the formation of [Mn III(sal-aebmz) 2]·ClO 4 (1). In the presence of triethylamine and using MnCl 2 under aerobic conditions, I forms [Mn III(sal- aebmz-H)(sal-aebmz)] (2). These complexes are characterised on the basis of elemental and electrochemical analyses, spectroscopic (IR and UV-Vis) data and thermogravimetric studies. Single crystal X-ray analysis of 2 shows that it is stabilized in the solid state through intermolecular hydrogen bonding between the NH groups of the two benzimidazole moieties after losing one of the hydrogen atoms; the coordination sites of the ligand are the imine nitrogen of the benzimidazole ring, the azomethine nitrogen and the deprotonated phenolic oxygen. Complex 2 catalyses the oxidative bromination of styrene by H 2O 2, yielding 1,2-dibromo-1-phenylethane, 1-phenylethane-1,2-diol and 2-bromo-1-phenylethane-1-ol, acting as a functional mimic of haloperoxidases. © 2012 Elsevier Ltd. All rights reserved.