Spectroscopic and computational characterization of Cu-II-OOR (R = H or cumyl) complexes bearing a Me-6-tren ligand

Abstract

A copper(II)–hydroperoxo complex, [Cu(Me6-tren)(OOH)]+ (2), and a copper(II)–cumylperoxo complex, [Cu(Me6-tren)(OOC(CH3)2Ph)]+ (3), were synthesized by reacting [Cu(Me6-tren)(CH3CN)]2+ (1) with H2O2 and cumyl-OOH, respectively, in the presence of triethylamine. These intermediates, 2 and 3, were successfully characterized by various physicochemical methods such as UV-vis, ESI-MS, resonance Raman and EPR spectroscopies, leading us to propose structures of the Cu(II)–OOR species with a trigonal-bipyramidal geometry. Density functional theory (DFT) calculations provided geometric and electronic configurations of 2 and 3, showing trigonal bipyramidal copper(II)–OOR geometries. These copper(II)–hydroperoxo and –cumylperoxo complexes were inactive in electrophilic and nucleophilic oxidation reactions.