The Character of Low-Lying Excited States of Mixed-Ligand Metal Carbonyls. TD-DFT and CASSCF/CASPT2 Study of [W(CO)4L] (L = ethylenediamine, N, N'-di-alkyl-1,4-diazabutadiene) and [W(CO)5L] (L = pyridine, 4-cyanopyridine)

0181599 - UFCH-W 20030026 RIV CZ eng J - Journal Article
Záliš, Stanislav - Vlček, Antonín - Daniel, CH.
The Character of Low-Lying Excited States of Mixed-Ligand Metal Carbonyls. TD-DFT and CASSCF/CASPT2 Study of [W(CO)4L] (L = ethylenediamine, N, N'-di-alkyl-1,4-diazabutadiene) and [W(CO)5L] (L = pyridine, 4-cyanopyridine).
Collection of Czechoslovak Chemical Communications. Roč. 68, č. 1 (2003), s. 89-104. ISSN 0010-0765
R&D Projects: GA MŠMT OC D14.20
Institutional research plan: CEZ:AV0Z4040901
Keywords : time dependent density functional * UV-VIS spectroscopy * DFT calculations
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.041, year: 2003

This contribution presents the results of the TD-DFT and CASSCF/CASPT2 calculations on [W(CO)4(MeDAB)] (MeDAB=N,N''-di-methyl-1,4-diazabutadiene), [W(CO)4(en)] (en = ethylenediamine), [W(CO)5(py)] (py=pyridine) and [W(CO)5(CNpy)] (CNpy=4-cyanopyridine) complexes. Contrary to the textbook interpretation, calculations on the model complex [W(CO)4(MeDAB)] and [W(CO)5(CNpy)] show that the lowest W MeDAB and WCNpy MLCT excited states are immediately followed in energy by several WCO MLCT states, instead of LF states. The lowest lying excited states of [W(CO)4(en)] system were characterized as W(COeq)2COax CT excitations, which involve a remarkable electron density redistribution between axial and equatorial CO ligands. [W(CO)5(py)] possesses closely lying WCO and Wpy MLCT excited states. The calculated energies of these states are sensitive to the computational methodology used and can be easily influenced by a substitution effect.
Permanent Link: http://hdl.handle.net/11104/0078142