Studies on polynuclear copper (II) complexes

A study has been made of the copper catalyst employed in the oxidative coupling of phenols and also of some polynuclear copper (II) complexes which are closely related to the catalyst system. The preparation of pyridine complexes of copper (I) halides and their characterisation by infrared spectra is described and the nature of these complexes in the solid state and in solution discussed. The preparation and properties of several new tetranuclear copper (II) complexes of the type cu4ox64L, where X is Cl or Br and L is a monodentate ligand, are described and, in addition, several of these tetranuclear complexes containing mixed halide bridges have been prepared for the first time and characterised. In theory, several of these mixed halide complexes should exhibit structural isomerism, and the two isomers of the complex cu40Cl2Br44py have been positively identified .from physical measurements. Tetranuclear copper (II) complexes have been shown to undergo halide, exchange reactions in solutions and from conductivity studies it is postulated that these complexes may well be considerably dissociated in solvents such as nitromethane. In addition, tetranuclear complexes with pyridine ligands have been shown to undergo redox decomposition reactions at temperatures above l50°C to yield copper {I) halide and a halopyridine....