Electrochemiluminescence in aqueous solution of a ruthenium(ii) bipyridyl complex containing a crown ether moiety in the presence of metal ions

Changes in electrochemiluminescence (ECL) properties of a ruthenium polyazine compound containing a crown-ether moiety have been investigated in aqueous buffered solution. The electrochemistry, photophysics and ECL of (bpy)2Ru(AZA-bpy)2+ [bpy = 2,2′-bipyridine; AZA-bpy = 4-(N-aza-18-crown-6-methyl-2,2′-bipyridine)] in the presence of Pb2+, Hg2+, Cu2+ and Ag+ are reported. Oxidation of (bpy)2Ru(AZA-bpy)2+ produces ECL in the presence of tri-n-propylamine (TPrA; 0.2 M KH2PO4). Increases in ECL efficiency (photons generated per redox event) greater than 2-fold have been observed that depend on both the concentration and nature of the metal ion, allowing the determination of ions not directly involved in the ECL reaction sequence.