Dimerization of Chlorocuprates in Weakly Polar Solvents

The solutions of CuCl₂ and tributylbenzylammonium chloride in chlorobenzene, which are used as catalysts for a number of processes with the participation of halogenated hydrocarbons, were studied by electronic spectroscopy in visible and UV regions. It was found that copper(II) ions occurred as two anionic chlorocuprate species (CuCl^2- ₄ and Cu₂Cl^2- ₆), which were in equilibrium, in solutions over wide ranges of concentrations and temperatures. The individual spectra of the two above chlorocuprate species were distinguished. The thermodynamic parameters of the equilibrium 2CuCl^2- ₄ Cu₂Cl^2- ₆ + 2Cl^– were calculated.