The d in 18 + d Electron Complexes: Importance of the Metal/Ligand Interface for the Substitutional Reactivity of \dqRe(0)\dq Complexes (a-diimine-)ReI(CO)3(X). Organometallics, (15)1:236--244, 1996. [PUMA: bidiazine bromo chloro complex complex;EPR diimine halo redn rhenium substitution;electrochem substitution;rhenium substitution;substitution]