0181608 - UFCH-W 20030036 RIV US eng J - Journal Article
Záliš, Stanislav - Farrell, I. - Vlček, Antonín
The Involvement of Metal-to-CO Charge Transfer and Ligand-Field Excited States in the Spectroscopy and Photochemistry of Mixed-Ligand Metal Carbonyls. A Theoretical and Spectroscopic Study of [W(CO)4(1,2-Ethylenediamine)] and [W(CO)4 (N,N''-Bis-alkyl-1,4-diazabutadiene)].
Journal of the American Chemical Society. Roč. 125, č. 15 (2003), s. 4580-4592. ISSN 0002-7863. E-ISSN 1520-5126
R&D Projects: GA MŠMT OC D14.20
Institutional research plan: CEZ:AV0Z4040901
Keywords : resonance-Raman-spectra * H bond activation * diimine complexes
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 6.516, year: 2003

A new interpretation of the electronic spectroscopy, photochemistry, and photophysics of group 6 metal cis-tetracarbonyls [M(CO)(4)L-2] is proposed, that is based on an interplay between M-->L and M-->CO MLCT excited states. TD-DFT and resonance Raman spectroscopy show that the lowest allowed electronic transition of [W(CO)(4)(en)] (en=1,2-ethylenediamine) has a W(COeq)(2)-->COax charge-transfer character, whereby the electron density is transferred from the equatorial W(COeq)(2) moiety to pi* orbitals of the axial CO ligands, with a net decrease of electron density on the W atom. The lowest, emissive excited state of [W(CO)(4)(en)] was identified as a spin-triplet W(COeq)(2)-->COax CT excited state both computationally and by picosecond time-resolved IR spectroscopy. This state undergoes 1.5 ps vibrational relaxation/solvation and decays to the ground state with a similar to160 ps lifetime.
Permanent Link: http://hdl.handle.net/11104/0078149