EPR evidence for related electronic structures of a-diimine complexes with bis(bipyridine)ruthenium(2+) (Ru(bpy)22+) and rhenium carbonyl(Re(CO)3)(halide) fragments. Chemical Physics Letters, (139)3-4:365--369, 1987. [PUMA: EPR ESR;electronic ESR;rhenium azobipyridine carbonyl diimine;photocatalyst diimine;pyridine halo rhenium structure]