Electrochemiluminescence Of Novel Precious Metal Complexes

At present, the ECL of organic transition metal complexes is an active research area, especially the Ru(bpy)32+ ECL has been used extensively immunoassays and DNA analyses. Ortho-metalated complexes of Ir(III) display strong visible absorptions and ground and excited-state redox potentials that, like their Ru(II) counterparts, make them of interest in fundamental and applied ECL. But these techniques have a major drawback is the need to constantly supply the reagent to the site of reaction, increasing both analysis costs and waste generated. Obviously, the immobilization of these reagents on a solid electrode surface can overcome the disadvantage. So this paper investigated the immobilization of some ECL reagent. The main results were given as follows:1. A ruthenium complex (bpy)2Ru(phenNH2)(PF6)2 was synthesized according to a method described in the literature, in which bpy is 2,2′-bipyridine, phenNH2 is 5-amino-1,10-phenan throline, then characterized by UV/vis spectroscopic and fluorescence spectroscopic. In 0.1mol/L TBAPF6,5mmol/L (bpy)2Ru(phenNH2)(PF6)2 acetonitrile solution, the complex was oxidative electropolymerized on to the surface of the glass carbon electrode. Then using TPA as coreactant, the steady ECL signals were obtained in both acetonitrile solution and aqueous solution.2. The solid-state ECL behavior of a water insoluble bis-cyclometalated (pq)2Ir (N-phMA) complex is presented, in which pq is a 2-phenylquinoline anion and N-phMA is N-phenyl methacrylamide, a monoanionic bidentate ligand. The MWNTs/ (pq)2Ir(N-phMA) film, MWNTs/ Ru(bpy)32+ film and (pq)2Ir(N-phMA) directly modi fied glassy carbon electrode were fabricated, only the MWNTs/(pq)2Ir(N-phMA) film can produce steady ECL in the presence of tri-n-propylamine as a coreactant.3. An o-phenanthroline-substituted ruthenium complex, [Rubis(bipyridyl)(3,4,7,8-tetrachr olo-1,10-phenanthroline)](PF6)2, has been synthesized and the structure of the complex was characterized by element analysis, IR spectroscopy and proton NMR spectroscopy. The complex displays absorptions in the UV and visible regions, with visible maximum absorption at 440 nm, a typical metal-to-ligand charge transfer (MLCT) transitions. Photoluminescence emission also has the characteristics of the MLCT transitions with the maxima wavelengths ranged from 630 to 649 nm depending on the different solvents. The ECL of the complex was found to be less dependant on the pH, which was distinctly different from that of the well known ruthenium tris(bipyridine) complex. Furthermore the background ECL signal of the complex did not increase even in a strong alkaline condition.