INVESTIGADORES
BERTOLOTTI Sonia Graciela
artículos
Título:
Photoreduction of Ru(bpy)32+ by amines in aqueous solution - Kinetics characterization of a long-lived non emitting excited state
Autor/es:
RIVAROLA, CLAUDIA R.; BERTOLOTTI, SONIA G; PREVITALI, CARLOS M.
Revista:
PHOTOCHEMISTRY AND PHOTOBIOLOGY
Editorial:
Elsevier Science
Referencias:
Lugar: Amsterdam; Año: 2006 vol. 82 p. 213 - 218
ISSN:
0031-8655
Resumen:
The photochemistry of Ru(bpy)3
12 in the presence of amines
was investigated in water by laser flash photolysis. N,N9-
Dimethylaniline and p-phenylenediamine quench the luminescent
metal to ligand charge transfer (MLCT) excited state of
the complex by an electron transfer reaction that produces the
semireduced form Ru(bpy)3
1 in relatively high yields. On the
other hand, triethylamine (TEA) and aniline do not quench
the MLCT. Nevertheless, when laser flash irradiation at 532
nm is carried out in the presence of these amines, the
formation of Ru(bpy)3
1 is clearly detected by its transient
absorption at 510 nm. These results are interpreted by an
electron transfer reaction with the participation of a nonemitting
excited state of the complex, formed independently of
the MLCT from the Franck-Condon or the relaxed singlet
excited state. The rate constants for the quenching of this state
by TEA and aniline and the quantum yields for Ru(bpy)3
1
were determined. The new state is formed in a very fast
process and has a lifetime of ca 4 ls in water.