Photo-oxidation of copper(I) chloro complexes: Individual quantum yields of [CuCl 2] − and [CuCl 2] −2

Abstract

The effects of the chloride and hydrogen ion concentrations on the photo-induced oxidation of copper(I) chloro complexes were investigated under continuous irradiation (λ = 253.7 nm). The spectrophotometric experimental method combined with computerized evaluation of the data gave results similar to those of experiments carried out earlier using the gas volumetric technique. The characteristics of the Φ versus C H+ 1 2 plots, i.e. the linearity at 0.1 M ⩽ C H+ < 1.0 M and the levelling off (saturation) at 1.0 M ⩽ C H+ ⩽ 3.0 M, at each chloride concentration examined indicate a Noyes geminate-pair scavenging mechanism where the electron formed in the photo-induced redox reaction undergoes competitive recombination and scavenging processes. The individual quantum yields of the copper(I) chloro complexes [CuCl 2] −[CuCl 3 2− where determined from their resolved spectra and the dependence of Φ on the chloride ion concentration. In the saturation region Φ 2/Φ 3 ≈ 2, i.e. the individual quantum yields for the electrons escaping primary recombination are Φ 2 = 0.60 Φ 3 = 0.29.