title: [Ru(phen)2(PHEHAT)]2+ and [Ru(phen)2(HATPHE)]2+: two ruthenium(II) complexes with the same ligands but different photophysics and spectroelectrochemistry.
abstract: The properties of two mononuclear Ru(II) complexes formed with the extended planar ligand PHEHAT depend drastically on the chelation site by the metallic ion. When the chelation takes place on the HAT site of the ligand (case of the novel complex [Ru(phen)2(HATPHE)]2+), the emission behavior is quite similar to that of [Ru(phen)2(HAT)]2+. In contrast, when the chelation is on the phen motif of the ligand (case of [Ru(phen)2(PHEHAT)]2+), the spectroscopic (absorption and emission) and electrochemical data for the complex do not obey the linear spectroelectrochemical correlation and the emission behavior is comparable to that of the extensively studied dppz complex ([Ru(phen/bpy)2(dppz)]2+). Thus, for [Ru(phen)2(PHEHAT)]2+, the emission lifetimes and intensities as a function of temperature exhibit a maximum for nitrile solvents. However, in contrast to the dppz case, at least three different states (two emitting and one dark) participate in the deactivation with different contributions depending on the temperature. These different contributions explain the observed maximum. Moreover, the fact that the solvent is liquid or frozen also influences the nature of the luminescent species.
authors.affiliation: Université Libre de Bruxelles, Chimie Organique et Photochimie, CP 160/08, 50 avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Boisdenghien
authors.forename: Cécile
authors.initials: C
authors.lastname: Moucheron
authors.forename: Andrée
authors.initials: A
authors.lastname: Kirsch-De Mesmaeker
mesh_terms: D004563:Electrochemistry / Q000379:methods; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D010777:Photochemistry; D010825:Physics / Q000379:methods; D017975:Ruthenium Compounds / Q000737:chemistry*; D013053:Spectrophotometry; D013816:Thermodynamics
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D017975:Ruthenium Compounds; C511542:bis(1,10-phenanthroline)(1,10-phenanthrolino(5,6-b)1,4,5,8,9,12-hexaaxatriphenylene)ruthenium(II)