title: Theoretical investigation on the photophysical properties of model ruthenium complexes with diazabutadiene ligands [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3).
abstract: In this study we report a theoretical comparative study of some photophysical properties in the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 0-3) series. Density functional theory calculations, validated by highly correlated ab initio benchmark calculations, were used to investigate the absorption and emission properties of the complexes with x = 1-3. The presence of a 1,4-diaza-1,3-butadiene (dab) ligand dramatically changes these properties because of the strong π-acceptor character of this ligand. As a result, comparing to the reference [Ru(bpy)(3)](2+) complex previously studied, we observed (i) a strong red-shift of the maximum of the absorption band, (ii) a strong decrease of the emission energy of the lowest triplet metal-to-ligand charge transfer state, with all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes luminescent in the near-infrared region, while [Ru(bpy)(3)](2+) emits in the visible region, and (iii) the triplet metal-centered states become inaccessible in all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes. Consequently, these complexes could be potential candidates for infrared light-emitting diodes and probes.
authors.affiliation: Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guillon
authors.forename: Martial
authors.initials: M
authors.lastname: Boggio-Pasqua
authors.forename: Fabienne
authors.initials: F
authors.lastname: Alary
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Heully
authors.forename: Emilie
authors.initials: E
authors.lastname: Lebon
authors.forename: Pierre
authors.initials: P
authors.lastname: Sutra
authors.forename: Alain
authors.initials: A
authors.lastname: Igau
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D008024:Ligands; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010777:Photochemistry; D011789:Quantum Theory; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D002070:Butadienes; D008024:Ligands; D009942:Organometallic Compounds; D012428:Ruthenium