Cyclometalated platinum(II) with ethynyl-linked azobenzene ligands: an original switching mode.
The photophysical properties of 6-phenyl-2,2'-bipyridyl platinum(ii) complexes bearing different σ-alkynyl-linked azobenzene ancillary ligands were investigated. These complexes exhibited strong, broad, structureless charge-transfer bands in the visible region, which were red-shifted when the electron-donating ability of the para substituent on the azo-acetylide ligand increased. When excited at the charge-transfer absorption band, the complexes exhibited weak green emission, which was assigned to a triplet metal-to-ligand charge transfer/interligand charge transfer emission ((3)MLCT/(3)L'LCT). The presence of an amino substituent in the azobenzene moiety opened the possibility of protonation, which led to the formation of an azonium based derivative and resulted in drastic perturbations of the molecular orbitals and photophysical properties of the Pt-acetylide complex. These studies are fully supported by DFT and TD-DFT calculations.
Institut des Sciences Chimiques de Rennes UMR 6226 CNRS-Université de Rennes 1, 35042, Rennes Cedex, France. jean-luc.fillaut@univ-rennes1.fr abdou.boucekkine@univ-rennes1.fr.
Paul
P
Savel
Camille
C
Latouche
Thierry
T
Roisnel
Huriye
H
Akdas-Kilig
Abdou
A
Boucekkine
Jean-Luc
JL
Fillaut