Tuning Photophysical and Electrochemical Properties of Cationic Iridium(III) Complex Salts with Imidazolyl Substituents by Proton and Anions

A series of cationic iridium(III) complex salts, 1−5, were synthesized containing different phenanthroline
derivatives. Their photophysical and electrochemical properties were investigated. The influences of anions
and proton on the photophysical and electrochemical properties were also studied in detail. Upon addition
of CF3COOH, the emission wavelength was significantly red-shifted and the emission color changed
from yellow to red. In addition, the addition of F-, CH3COO-, and H2PO4- can also cause significant
variations in UV−vis absorption and emission spectra. Upon addition of F-, CH3COO-, and H2PO4-,
the solution colors of 1−3 changed from yellow-green to brown and the emission of 1−3 was quenched
completely, which can be observed by the naked eye.