ESR of arene complexes of Co(II) and Co(0)

The formation of metal-complex catalysts in solutions of aromatic hydrocarbons is often accompanied by the formation of bis- and monoarene paramagnetic complexes, which are identified with the aid of ESR. The theoretical dependence of the components of the g factor on the angular distortions in bisaromatic compounds of transition metals with d/sup 7/ and d/sup 9/ electronic configurations has been determined in the framework of crystal-field theory for the purpose of developing an ESR method for structural investigations of aromatic complexes. Satisfactory agreement between the calculated values and the experimental data for individual compounds has been obtained. The results of the calculations has been used to determine the number of coordinated alkylbenzene molecules in Co(II) and Co(0) complexes which form in catalytic systems.