Supramolecular systems in which the -Ru(NH3) electron acceptor unit is linked via a cyanide bridge to polychromophoric complexes of the type [NC-Ru-(bpy)2-CN-[Ru(bpy)2-NC-]nRu(bpy)2-CN](n+1)+ (n = 0, 1; bpy = 2,2'-bipyridine) have been synthesized and their electrochemical and photophysical properties have been studied. In such systems the lowestenergy -Ru(bpy)-chromophore is not the one adjacent to the -Ru(NH3)l+ acceptor, but rather the next one. In all cases, however, complete quenching of the excited states of the polychromophoric assembly has been observed, indicating efficient photoinduced electron transfer to the acceptor. For [NC-Ru(bpy)2-CN-Ru(bpy)2-NC-Ru(bpy)2-CN-Ru(NH3)5]5t, the process has been directly observed by picosecond absorption spectroscopy. The rate constant for charge recombination is 7 x 108 s~1, consistent with the involvement of remote metal centers in the process. © CNRS-Gauthier-Villars.
Intramolecular Electron Transfer in Cyano-bridged Polynuclear Complexes
BIGNOZZI, Carlo Alberto;ARGAZZI, Roberto;BORTOLINI, Olga;SCANDOLA, Franco
1996
Abstract
Supramolecular systems in which the -Ru(NH3) electron acceptor unit is linked via a cyanide bridge to polychromophoric complexes of the type [NC-Ru-(bpy)2-CN-[Ru(bpy)2-NC-]nRu(bpy)2-CN](n+1)+ (n = 0, 1; bpy = 2,2'-bipyridine) have been synthesized and their electrochemical and photophysical properties have been studied. In such systems the lowestenergy -Ru(bpy)-chromophore is not the one adjacent to the -Ru(NH3)l+ acceptor, but rather the next one. In all cases, however, complete quenching of the excited states of the polychromophoric assembly has been observed, indicating efficient photoinduced electron transfer to the acceptor. For [NC-Ru(bpy)2-CN-Ru(bpy)2-NC-Ru(bpy)2-CN-Ru(NH3)5]5t, the process has been directly observed by picosecond absorption spectroscopy. The rate constant for charge recombination is 7 x 108 s~1, consistent with the involvement of remote metal centers in the process. © CNRS-Gauthier-Villars.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
