Generation and characterisation of the phenoxyl-radical containing Cu(ii) complex [Cu(triaz)2]+ (triaz− = O,N chelating triazole-phenolate)

Abstract

The new copper complex [Cu(triaz)₂] (Htriaz = 2,4-di-(tert-butyl)-6-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)phenol) was investigated in detail by single crystal XRD, EPR-, UV/Vis-absorption-, CV-, and spectroelectrochemistry. The oxidised species [Cu(triaz)₂]⁺ was characterised by UV/Vis spectroelectrochemistry and contains a phenoxyl-radical bound to Cu(II). This quite stable species was chemically generated by two different methods: aerial oxidation of a Cu(I) precursor in the presence of Htriaz (and base) or from [Cu(triaz)₂] by adding a Cu(II) salt (disproportionation). The efficiency for the latter reaction has been studied by UV/Vis spectroscopy, XAS and catalytic test reactions (oxidation of benzyl alcohol).