Origin of electronic absorption spectra of MLCT-excited and one-electron reduced 2,2′-bipyridine and 1,10-phenanthroline complexes

0361412 - ÚFCH JH 2012 RIV NL eng J - Journal Article
Záliš, Stanislav - Consani, C. - Nahhas, A. E. - Cannizzo, A. - Chergui, M. - Hartl, F. - Vlček, Antonín
Origin of electronic absorption spectra of MLCT-excited and one-electron reduced 2,2′-bipyridine and 1,10-phenanthroline complexes.
Inorganica chimica acta. Roč. 374, č. 1 (2011), s. 578-585. ISSN 0020-1693. E-ISSN 1873-3255
R&D Projects: GA MŠMT(CZ) LD11082; GA MŠMT LD11086
Institutional research plan: CEZ:AV0Z40400503
Keywords : TDDFT * diimines * spectroelectrochemistry
Subject RIV: CG - Electrochemistry
Impact factor: 1.846, year: 2011

UV–Vis absorption spectra of one-electron reduction products and 3MLCT excited states of [ReICl(CO)3(N,N)] (N,N = 2,2′-bipyridine, bpy; 1,10-phenanthroline, phen) have been measured by low-temperature spectroelectrochemistry and UV–Vis transient absorption spectroscopy, respectively, and assigned by open-shell TD-DFT calculations. The characters of the electronic transitions are visualized and analyzed using electron density redistribution maps. It follows that reduced and excited states can be approximately formulated as [ReICl(CO)3(N,Nradical dot−)]− and *[ReIICl(CO)3(N,Nradical dot−)], respectively. UV–Vis spectra of the reduced complexes are dominated by IL transitions, plus weaker MLCT contributions. Excited-state spectra show an intense band in the UV region of not, vert, similar50% IL origin mixed with LMCT (bpy, 373 nm) or MLCT (phen, 307 nm) excitations. Because of the significant IL contribution, this spectral feature is akin to the principal IL band of the anions.
Permanent Link: http://hdl.handle.net/11104/0198727