Influence of the nuclearity of copper(II) chloride complexes on their activity in catalytic C-Cl bond metathesis

Abstract

Catalytic systems containing mainly mononuclear (CuCl42−) or dinuclear (Cu2Cl62−) tributylbenzylammonium chlorocuprates are prepared by adsorption on silica surfaces of different structures (Aerosil and Silokhrom). Using ESR, XANES, and electronic spectroscopy, the CuCl42− ions are shown to be reduced rapidly under conditions of C-Cl bond metathesis, whereas the dinuclear chlorocuprates are relatively stable. A correlation between the number of copper ions in the chlorocuprate anion and its catalytic activity is established: the mononuclear complexes are several times more active than their dinuclear counterparts.