Electrochemiluminescence studies of the cyclometalated iridium(III) complexes with substituted 2-phenylbenzothiazole ligands

Electrogenerated chemiluminescence (ECL) studies have been performed for the iridium(III) cyclometalated L2Ir(acac) complexes with substituted 2-phenylbenzothiazole ligand L. Electron transfer (ET) generation of the excited (3)*L2Ir(acac) has been studied using a triple-potential-step technique in acetonitrile-dioxane (1:1) solutions containing 0.1 M (n-C4H9)(4)NPF6 as the supporting electrolyte. ET reactions between electrochemically generated L2Ir(acac)(+) and A(-) (radical anions of aromatic nitriles) species lead to very efficient generation of ECL emission. Extremely high ECL efficiencies (up to 0.40) close to the excited (3)*L2Ir(acac) luminescence yields have been found. (C) 2004 Elsevier B.V. All rights reserved.