Photophysical properties of homometallic ruthenium(II) and osmium(II) complexes with a bis(dipyridophenazine) bridging ligand. From pico- to microsecond time resolution
Articolo
Data di Pubblicazione:
2002
Citazione:
Photophysical properties of homometallic ruthenium(II) and osmium(II) complexes with a bis(dipyridophenazine) bridging ligand. From pico- to microsecond time resolution / M. Staffilani, P. Belser, F. Hartl, C.J. Kleverlaan, L. De Cola. - In: JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY. - ISSN 1089-5639. - 106:40(2002 Oct 10), pp. 9242-9250. [10.1021/jp026002i]
Abstract:
The photophysical properties of [Ru-bidppz-Ru]4+, [Os-bidppz-Os]4+, and the bridging ligand bidppz (bidppz = 1,1′-dipyrido[3,2-a:2′,3′-c]phenazin-1,1′-yldipyrido[3,2 -a:2′,3′-c]phenazme) are investigated. Time-resolved spectroscopic studies were performed on (sub)pico- to microsecond time scales, offering insight into the excited states responsible for the photophysical behavior of the two complexes in different solvents. In particular, [Ru-bidppz-Ru]4+ shows a long excited-state lifetime, 9.7 μs, in deaerated dichloromethane solution, that becomes much shorter (360 ns) in deaerated butyronitrile. The solvent plays a crucial role for the spectroscopic properties of this complex, since the energy of the triplet metal-to-ligand charge-transfer (3MLCT) excited state is influenced by the polarity of the medium. (Sub)picosecond transient absorption spectra in dichloromethane indicate thermal population of the long-lived triplet intraligand (3IL) state of the bridging ligand from the lower lying 3MLCT state. For [Os-bidppz-Os]4+ in dichloromethane the 3MLCT state lies lower in energy and no interaction of this state with the 3IL state of the bridging ligand is observed.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Staffilani, P. Belser, F. Hartl, C.J. Kleverlaan, L. De Cola
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