Synthesis and reactivity of a mononuclear non-haem cobalt(IV)-oxo complex

OpenAlex İngilizce

Abstract Terminal cobalt(IV)–oxo (Co IV –O) species have been implicated as key intermediates in various cobalt-mediated oxidation reactions. Herein we report the photocatalytic generation of a mononuclear non-haem [(13-TMC)Co IV (O)] 2+ ( 2 ) by irradiating [Co II (13-TMC)(CF 3 SO 3 )] + ( 1 ) in the presence of [Ru II (bpy) 3 ] 2+ , Na 2 S 2 O 8 , and water as an oxygen source. The intermediate 2 was also obtained by reacting 1 with an artificial oxidant (that is, iodosylbenzene) and characterized by various spectroscopic techniques. In particular, the resonance Raman spectrum of 2 reveals a diatomic Co–O vibration band at 770 cm −1 , which provides the conclusive evidence for the presence of a terminal Co–O bond. In reactivity studies, 2 was shown to be a competent oxidant in an intermetal oxygen atom transfer, C–H bond activation and olefin epoxidation reactions. The present results lend strong credence to the intermediacy of Co IV –O species in cobalt-catalysed oxidation of organic substrates as well as in the catalytic oxidation of water that evolves molecular oxygen.