Copper complexes with non-innocent ligands: Probing CuII/catecholato-CuI/o-semiquinonato redox isomer equilibria with EPR spectroscopy. Inorganica Chimica Acta, (337):163--172, 2002. [PUMA: transfer aminoethylphosphine semiquinonato catecholato complex copper EPR;crystal electron structure;copper prepn structure]