Reactivity of Copper(III)-Oxo Complexes in the Gas Phase

Abstract

An efficient way to generate [(L)CuO]⁺ complexes with a number of monodentate and bidentate ligands (L) from their [(L)Cu(ClO₃ )]⁺ precursors by electrospray ionization was herein explored. Further, we studied [(L)CuO]⁺ with L=9,10-phenanthraquinone, 1,10-phenanthroline, and acetonitrile in detail. The signature of these terminal copper-oxo complexes was found to be elimination of the oxygen atom upon collisional activation. We investigated and compared their reactions with water, ethane, ethylene, and 1,4-cyclohexadiene. The [(MeCN)CuO]⁺ complex oxidized water and performed C-H activation and hydroxylation of ethane. The complexes with bidentate ligands did not react with water and oxidized only larger hydrocarbons. All the investigated complexes showed comparable reactivities in the oxygen-transfer reaction with ethylene.

Keywords: C−H activation; IR spectroscopy; copper; gas-phase reactivity; oxygen transfer.