Dinuclear Asymmetric Ruthenium Complexes with 5-Cyano-1,10-phenthroline as a Bridging Ligand

MELLACE, MARÍA G.; FAGALDE, FLORENCIA; KATZ, NÉSTOR E.; CRIVELLI, IRMA G.; DELGADILLO, ALVARO; LEIVA, ANA MARÍA; LOEB, BÁRBARA; GARLAND, MARÍA TERESA; BAGGIO, RICARDO

INORGANIC CHEMISTRY

American Chemical Society

Lugar: Washington D.C.; Año: 2004 vol. 43 p. 1100 - 1107

0020-1669

New dinuclear asymmetric complexes of ruthenium of the type : [(bpy)2Ru(5-CNphen)Ru(NH3)5]4+/5+ (bpy = 2,2'-bipyridine; 5-CNphen = 5-cyano-1,10-phenanthroline) have been synthesized and characterized by spectroscopic, electrochemical and photophysical techniques. The structure of the cation [(bpy)2Ru(5-CNphen)Ru(NH3)5]4+ has been determined by X-ray diffraction. The mononuclear precursor [Ru(bpy)2(5-CNphen)]2+ has also been prepared and studied; while its properties as a photosensitizer are similar to those of  [Ru(bpy)3]2+, its luminescence at room temperature is quenched by a factor of 5 in the mixed-valent species  [(bpy)2RuII(5-CNphen)RuIII(NH3)5]5+,  pointing to the occurrence of intramolecular electron transfer processes that follow light excitation. From spectral data of the metal-to-metal charge transfer transition RuII ®  RuIII in this latter complex, a slight electronic interaction (HAB = 190 cm -1) is disclosed between both metallic centers through the bridging 5-CNphen.