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One-electron reduction of the complexes (Re(Br)(CO)3(R'-DAB)) in nPrCN has led to the establishment of an equilibrium between the radical anions and the solvento radical. The Re-Br bond becomes more stable with the electron-withdrawing character of R' and with decreasing temperature. Reduction of the radicals can be undertaken in a subsequent one-electron step to give the five-coordinate anions, together with the six-coordinate anions, as the minor products.

The lowest energy electronic transition of Re(X)(CO)3(alpha-diimine) (X = Cl, Br, I; alpha-diimine = bpy, iPr-PyCa, iPr-DAB) changes from Re to alpha-diimine (MLCT) to X to alpha-diimine (XLCT) on moving from Cl to Br. Resonance Raman spectra and time-resolved absorption and emission spectroscopy show that the change in excited state is attributed to an irregular mixing of the d(sub pi)(Re) and p(sub pi)(X) orbitals. The emission from the XLCT excited state exhibits a longer lifetime due to the slow nonradiative decomposition to the ground state.

Time-resolved UV-vis absorption spectroscopy and nano-second flash photolysis analyze the photoreactions of three (CO)(5)ReMn(CO)(3) (alpha-diimine) complexes at different temperatures and pressures. Primary photoprocess in the metal-to-ligand charge-transfer excitation of these complexes is a fast CO dissociation from Mn center. High reactivities of these complexes are due to an available Mn coordination site and a weak Re-M bond.

Describes the reduction routes of inorganic complexes and metal-alkyl complexes, using data obtained from IR and UV-vis spectroelectrochemical measurements and cyclic voltammetry at variable temperatures. Materials and preparations; IR spectral changes in the carbonyl stretching region during the reduction; Establishment of a one-electron reduction.