Synthesis, electrochemical and electrogenerated chemiluminescence studies of ruthenium(II) Bis(2,2'-bipyridyl)[2-(4-methylpyridin-2-yl)benzo[d]-X-azole]

A series of photoactive complexes of [Ru(II)bis(bipyridyl){2-(4-methylpyridin-2-yl)benzo[d]-X-azole)](PF6)(2) (X = N-CH3, 1; S, 2; or O, 3) have been synthesized and fully characterized by proton and C-13 NMR spectroscopy and UV/Vis spectroscopy. The X-ray structure of I is also reported. The electrochemical behavior and the photophysical properties of 1-3 have been investigated. Cyclic voltammetry (CV) reveals the presence of three consecutive one-electron reduction processes and a single one-electron oxidation process that are chemically and electrochemically reversible. In all cases, electrogenerated chemiluminescence (ECL) has been observed in the presence of the co-reactant tri-n-propylamine (TPA). An analogue of 1 has been synthesized, [Ru(II)bis(bipyridyl) {2-(4-methylpyridin-2-yl)benzo[d]-X-azolel] (PF6)(2) [X = N(CH2)(5)CO2H, 4], it has been coupled with bovine serum albumin (BSA), and its photophysical properties investigated. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).