LAUSR

Abstract Ru(II)-polypyridine complexes of the general formula [Ru(L1/L2)(phen)2]X2 (1a–6a) and [Ru(L1/L2)(bipy)2]X2 (1b–6b) (where X = ClO4, BF4, PF6; phen = 1,10-phenanthroline, bipy = 2,2′-bipyridine) were prepared by the reaction of [Ru(phen)2Cl2]·2H2O and [Ru(bipy)2Cl2]·2H2O with (E)-5-((4-methoxyphenyl)ethynyl)-N-(pyridin-2-ylmethylene)pyridin-2-amine (L1) and (E)-5-((4-nitrophenyl)ethynyl)-N-(pyridin-2-ylmethylene)pyridine-2-amine (L2) in the presence of NaBF4, NaClO4, and NaPF6. The electrochemical properties of all the complexes indicate reversible redox behavior corresponding to Ru(II)–Ru(III) couple and are susceptible to variation of electron-donating/accepting properties of substituent group on L1 and L2. All complexes showed room temperature luminescence corresponding to π→π* intra-ligand charge-transfer (ILCT) transition with chelation enhanced fluorescence and is finely tuned by increasing π-conjugation, size of counter anions, and variation of substituent group with different electronic effects in the complexes. All the complexes worked as an effective catalyst for the oxidation of benzyl alcohol to corresponding benzaldehyde in good yield at room temperature. Graphical Abstract