Mononuclear copper (ll) aspirinate or salicylate complexes with methylimidazoles as biomimetic catalysts for oxidative dealkylation of a hindered phenol, oxidation of catechol and their superoxide scavenging activities

Abstract

Mononuclear complex bis(aspirinato) bis(2-methylimidazole) copper(II), Cu(asp)2 (2-MeIm)2 (1), has been synthesized and spectroscopically characterized. The biomimetic catalytic activities of this complex and our previously characterized complexes, Cu(asp)2 (1,2-MeIm)2 (2), Cu(Hsal)2 (1,2-MeIm)2 (3), and Cu(sal)(2-MeIm)3, (4) [H2sal = salicylic acid and MeIm = methylimidazole], for the oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone and the oxidative dealkylation of 2,4,6-tri-tert-butylphenol to 2,6-di-tert-butyl-1,4-benzoquinone and 4,6-di-tert-butyl-1,2-benzoquinone as the main products are reported. Complexes 1 and 2 are found to be potent SOD mimics and their SOD activities are compared with those obtained previously for complexes 3 and 4. Graphical AbstractMononuclear copper(II) aspirinate or salicylate complexes with methylimidazole ligands were found to catalyze the oxidation of 3,5-di-tert-butylphenol to corresponding o-quinone and the oxidative dealkylation of 2,4,6-tri-tert-butylphenol (TTBP) to o-DTBQ and p-DTBQ. The complexes are potent SOD mimics.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► Mononuclear bis(aspirinato) bis (2-methylimidazole) copper(II) has been synthesized and characterized. ► Mononuclear copper(II) aspirinate and salicylate complexes with methylimidazole ligands are used to catalyze the oxidation of DTBC and oxygenation of TTBP