title: Enhancement of luminescence lifetimes of mononuclear ruthenium(II)-terpyridine complexes by manipulation of the sigma-donor strength of ligands.
abstract: The synthesis and characterization of mixed ligand 2,2';6',2' '-terpyridine (tpy) ruthenium complexes with 2,6-bis([1,2,4]triazol-3-yl)pyridine, 2,6-bis(5-phenyl-[1,2,4]triazol-3-yl)pyridine, and 2,6-bis([1,2,3,4]tetrazol-5-yl)pyridine are reported. The species are characterized by HPLC, 1H NMR, UV/vis, and emission spectroscopy. The photophysical properties of the complexes are investigated as a function of temperature over the range 80-320 K. The emission lifetime observed for the fully deprotonated compounds at room temperature is about 80 ns. This increase by 2 orders of magnitude with respect to the parent "[Ru(tpy)2](2+)" complex is rationalized by an increase in the energy of the metal based dsigma orbital, rather than by manipulation of the pi* orbitals on the ligands. The acid-base and electrochemical properties of the compounds are reported also.
authors.affiliation: National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Marco
authors.initials: M
authors.lastname: Duati
authors.forename: Stefania
authors.initials: S
authors.lastname: Tasca
authors.forename: Fiona C
authors.initials: FC
authors.lastname: Lynch
authors.forename: Holger
authors.initials: H
authors.lastname: Bohlen
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Vos
authors.forename: Stefano
authors.initials: S
authors.lastname: Stagni
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ward