A combined spectroscopic, photophysical and theoretical (DFT) study of the electronically excited inorganometallic complexes [Ru(E)(E′)(CO)2(iPr-DAB) ] (E = Cl, Me, SnPh3, PbPh3; E′ = GePh3, SnR3, PbR3 (R = Me, Ph); iPr-DAB = N,N′-diisopropyl-1,4-diaza-1,3-butadiene): Evidence of an exceptionally long-lived 3σπ* excited state for [Ru(SnPh3)2(CO)2(iPr-DAB)]

Maxim P. Aarnts, Derk J. Stufkens, Maikel P. Wilms, Evert Jan Baerends, Antonín Vlček, Ian P. Clark, Michael W. George, James J. Turner

Research output: Journal PublicationArticlepeer-review

58 Citations (Scopus)

Abstract

The photophysical properties of the metal-metal bonded complexes [Ru(E)(E′)(CO)2(iPr-DAB)] (E = Cl, E′ = SnPh3, PbPh3; E = Me, E′ = SnPh3, PbPh3; E = SnPh3, E′ = SnMe3, SnPh3, GePh 3; E = PbPh3, E′ = PbMe3, PbPh 3, GePh3; iPr-DAB = N,N′-diisopropyl-1,4-diaza-1,3- butadiene) have been studied. According to time-resolved emission, UV/vis and IR spectra, combined with density functional (DFT) MO calculations, the lowest excited state has triplet metal-to-ligand charge-transfer (3MLCT), triplet halide-to-ligand charge-transfer (3XLCT) or 3σ(E-Ru-E′)π* character, depending on the nature and combination of the ligands E and E′. The 3σ(E-Ru-E′)π* state is a bound state whose lifetime is strongly influenced by the ligands E and E′. An exceptionally long lifetime (264 μs at 80 K) is observed for the 3σ(Sn-Ru-Sn)π* state of the symmetrically substituted [Ru(SnPh3)2(CO)2(iPr-DAB)] complex. The reason for this long lifetime is the fact that the excited state of this complex is hardly distorted with respect to the ground state, owing to the delocalised character of the σ(Sn-Ru-Sn) bonding orbital, which mixes strongly with the π* orbital of the iPr-DAB ligand. This delocalisation is also responsible for the unusually high oscillator strength of the σ → π* electronic transition in the visible spectral region.

Original languageEnglish
Pages (from-to)1556-1565
Number of pages10
JournalChemistry - A European Journal
Volume2
Issue number12
DOIs
Publication statusPublished - 1996
Externally publishedYes

Keywords

  • Density functional calculations
  • IR spectroscopy
  • Ruthenium complexes
  • Time-resolved spectroscopy
  • UV vis spectroscopy

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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