New dinuclear and mixed-valent complexes of rhenium and ruthenium bridged by heterocycles ligands

MELLACE, MARÍA G.; FAGALDE, FLORENCIA; KATZ, NÉSTOR E

POLYHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2003 vol. 22 p. 369 - 374

0277-5387

Two new mixed-metal mixed-valent complexes, of formulae: [(CO)3(bpy)ReI(bpe)RuIII(NH3)5]4 and [(CO)3(bpy)ReI(4-valent complexes, of formulae: [(CO)3(bpy)ReI(bpe)RuIII(NH3)5]4 and [(CO)3(bpy)ReI(4- 14 //CNpy)RuIII(NH3)5]4 (where bpy/2,2?-bipyridine, bpe/trans -1,2-bis(4-pyridil)ethene, 4-CNpy/4-cyanopyridine), were pre-//CNpy)RuIII(NH3)5]4 (where bpy/2,2?-bipyridine, bpe/trans -1,2-bis(4-pyridil)ethene, 4-CNpy/4-cyanopyridine), were pre- 15 //pared and characterized as solids and in acetonitrile solutions. From their spectroscopic, electrochemical and photophysical//pared and characterized as solids and in acetonitrile solutions. From their spectroscopic, electrochemical and photophysical 16 //properties, the values for the reorganization energies l and electronic coupling elements HAB for the metal-to-metal intramolecular//properties, the values for the reorganization energies l and electronic coupling elements HAB for the metal-to-metal intramolecular 17 //electron transfers mediated by the N-heterocyclic bridges were calculated, using the Marcus/Hush formalism. For the 4-CNpy//electron transfers mediated by the N-heterocyclic bridges were calculated, using the Marcus/Hush formalism. For the 4-CNpy 18 //derivative, the reverse ruthenium-to-rhenium charge recombination*/that should follow light excitation*/is expected to be in the//derivative, the reverse ruthenium-to-rhenium charge recombination*/that should follow light excitation*/is expected to be in the 19 //normal region, while for the bpe derivative this reaction is predicted to lie in the inverted region. The differences in redox potentials//normal region, while for the bpe derivative this reaction is predicted to lie in the inverted region. The differences in redox potentials 20 //and in l for both species account for these changes, which are relevant in the design of efficient photoconverters.//and in l for both species account for these changes, which are relevant in the design of efficient photoconverters. 21 //# 2002 Elsevier Science Ltd. All rights reserved.//# 2002 Elsevier Science Ltd. All rights reserved.