Enhancement of luminescence lifetimes of mononuclear ruthenium(II)-terpyridine complexes by manipulation of the sigma-donor strength of ligands.
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.
Duati
Marco
M
National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Tasca
Stefania
S
Lynch
Fiona C
FC
Bohlen
Holger
H
Vos
Johannes G
JG
Stagni
Stefano
S
Ward
Michael D
MD