Unusual Stability of an end-on Superoxido Copper(II) Complex under Ambient Conditions.

Abstract

Superoxido copper complexes play an important role as usually short-lived intermediates in biology and chemistry. The unusual stability of anend-onsuperoxido copper complex observed in an oxygen-enhanced atom transfer radical polymerization (ATRP) led to a detailed mechanistic investigation of the formation of [CuII(Me6tren)(O2•-)]+(Me6tren = tris(2-dimethyl-aminoethyl)amine) under ambient conditions. The persistence of the superoxido copper complex could be explained by a reaction cycle including the peroxido complex[(Me6tren)2CuII2(O2)]2+together with [CuI(Me6tren)(DMSO)]+and [CuII(Me6tren)(OH)]+in the overall reaction.