On the nature of the redox products of 4-((CH3)2N)C6H4-CO2- and 4-((CH3)2N)C6H4-CO2-Re(CO)3(1,10-phenanthroline):: A spectroelectrochemical, pulse radiolysis and flash photochemical study

The UV-Vis absorption spectra of 4-dimethylaminobenzyl radical cation (DMAB(center dot+)) and 1,10-phenanthroline radical anion (phen(center dot-)) were obtained by spectroelectrochemistry, flash photolysis and pulse radiolysis experiments on DMAB-CO2-Re-I(CO)(3)(phen) and DMAB-COOH. DMAB-CO2-Re-I(CO)(3)(phen) was shown to have remarkable reversibly/stable redox processes under electrochemical perturbations. An excellent agreement was observed between the spectrum of the radical cation DMAB(center dot+) obtained electrochemically and radiolytically. The in situ UV-Vis spectrum of the electrochemically reduced radical anions, phen(center dot-), was compared with that obtained from the products of the reductive quenching of the corresponding photochemically excited states. Besides, the oxidative quenching of the Re-I complex excited states by [Ni-II(Me-6[14]-aneN(4))] showed the formation of [(DMAB(center dot+)-CO2)-Re-I(CO)(3)(phen)] as the main primary product. (C) 2008 Elsevier Ltd. All rights reserved.