Photoinduced charge separation in R–CO2–Re(CO)3(2,2′-bipyridine) complexes. Two emitting charge transfer excited states
Wolcan, E.; Torchia, G.; Tocho, J.; Piro, O. E.; Juliarena, P.; Ruiz, G.; Féliz, M. R.; Wolcan E.; INIFTA(CONICET-CICBA), Fac. Cs. Exactas, Universidad Nacional de La Plata, C.C. 16; Torchia G.; CIOp(CICBA-CONICET), C.C. 124; Tocho J.; CIOp(CICBA-CONICET), C.C. 124; Piro O. E.; Department of Physics, Fac. Cs. Exactas, Universidad Nacional de La Plata and IFLP(CONICET); Juliarena P.; INIFTA(CONICET-CICBA), Fac. Cs. Exactas, Universidad Nacional de La Plata, C.C. 16; Ruiz G.; INIFTA(CONICET-CICBA), Fac. Cs. Exactas, Universidad Nacional de La Plata, C.C. 16; Féliz M. R.; INIFTA(CONICET-CICBA), Fac. Cs. Exactas, Universidad Nacional de La Plata, C.C. 16
Журнал:
Journal of the Chemical Society, Dalton Transactions
Дата:
2002
Аннотация:
Excited state properties of the newly prepared complexes Râ CO2â Re(CO)3(2,2â ²-bipy), where Râ CO2<sup>â </sup> = naphthalene-2-carboxylate, anthracene-9-carboxylate, pyrene-1-carboxylate and acetate, were investigated by steady state and time resolved spectroscopy. The X-ray structure revealed that the R containing ligand is coordinated through the carboxylate group to Re(i). Results showed that two emitting excited states play a major role in the photophysics of the complexes. The fast component of the complexes luminescence was associated with the charge transfer excited state, MLCT, Re-to-2,2â ²-bipyridine, while experimental evidence led to the long lived component being attributed to a ligand-to-ligand charge transfer excited state. This emissive LLCT excited state can also evolve to a photodissociative state which ultimately produces the complex decarboxylation. On the other hand, the carboxylate bridge was shown to be able to impede connection between R and the Re(CO)3(2,2â ²-bipy) chromophore.
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