Synthesis, Spectroscopic Characterization, and Oxidative C-C Coupling in New Copper(II) Salicylaldiminates Containing Sterically Hindered Phenol

Abstract

New bis[N-(2,6-di-tert-butyl-1-hydroxyphenyl)salicylideneminato]copper(II) complexes bearing HO and CH<inf>3</inf>O substituents on the salicyaldehyde moiety were prepared, and have been characterized by elemental analyses, IR, UV/Vis, ESR spectroscopy, and magnetic moments. It has been found that in the synthesis of CH<inf>3</inf>O substituted complexes unlike HO bearing, the oxidative C-C coupling of coordinated salicylaldimine ligands take place. It has been suggested that the intermolecular H-bonding is a dominant factor in controlling of oxidative C-C coupling conversion. The powder ESR spectra of CH<inf>3</inf>O substituted compounds unlike of HO are typical of a triplet state CuII dimers with a half-field forbidden (ΔM = ± 2) and the allowed (ΔM = ± 1) transitions at 300 and 113 K. © WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001.