Ligand decomposition in the photolysis of copper(II)–amino-acid complexes in aqueous solution

Abstract

Ligand decomposition following charge-transfer excitation of bis(glycinato)cuprate(II) in aqueous solution gives NH₃ and HCHO as the final products in yields equivalent to the reduction of the metal to Cu^I. An intermediate, observed by flash photolysis, is believed to be the Cu—C-bonded species, CuCH₂NH₂. The reaction mechanism is discussed for the process in deaerated solution and in O₂-saturated solution, where H₂O₂ is formed in addition to the ligand-decomposition products. Cu(α-alanine)₂ shows photolytic behaviour similar to that of the glycine complex.