Cu(III)–bis-thiolato complex forms an unusual mono-thiolato Cu(III)–peroxido adduct.

The stable complex [bis(toluene-3,4-dithiolato)copper(III)][NEt3H] has been synthesised and characterised as a square-planar Cu(III) complex by X-ray photoelectron spectroscopy, cyclic voltammetry and DFT calculations. Intriguingly, when fragmented in FTICR-MS, an unusual [(toluene-3,4-dithiolate)Cu(III)(peroxide)]− complex is formed by reaction with oxygen. Natural 1,2-dithiolenes known to bind molybdenum might stabilise Cu(III) in vivo. [ABSTRACT FROM AUTHOR]