Tuning Photophysical and Electrochemical Properties of Phosphorescent Heteroleptic Iridium Complex Salts-as Chemosensors.

Photophysical and electrochemical studies of cyclometalated cationic heteroleptic iridium(III) complex salts have been carried out. For these complex salts the intense absorption bands appeared around 263 nm and are assigned to spin-allowed π-π* transitions of phenanthroline ligands. Moderately intense and weak absorption bands observed around 341 and 440 nm, respectively. These bands are assigned to spin-allowed metal to ligand charge transfer (1)MLCT and (3)MLCT transitions, respectively. The influence of anions and proton on the photophysical and electrochemical studies were also carried out. The emission wavelength was red shifted and emission color changed from yellow to red by the addition of CF3CO2H. The solution color changed from green to brown and the emission was quenched by the addition anions such as of F(-), CH3COO(-) and H2PO4(-).