Spectroscopic and electrochemical properties of mixed-ligand cyclopalladinized complexes of deprotonated forms of 2-(2-thienyl)pyridine and 2-phenylpyridine with 1,10-phenantroline and its 1,4-diazine derivatives

A comparative study of Pd(N?C)(N?N)]⁺ complexes {(N?C)^? are deprotonated forms of 2-phenylpyridine and 2-(2-thienyl)pyridine and (N^N) is 1,10-phenantroline, dipyridof,h]quinoxaline, dipyridoa,c]phenazine or 6,7-dicyanodibenzof,h]quinoxaline} was carried out by the methods of ¹H NMR, electronic absorption and emission spectroscopy, and cyclic voltammetry. Optical and electrochemical properties of dipyrido-substituted 1,4-diazines are conditioned by the electron transfer involving π* orbitals localized on weakly interacting phenantroline (π*_phen) and diazne (π*_diaz) components.