A comparative study on electrochemiluminescent properties of a series of ruthenium(II) complexes

Electrochemiluminescent (ECL) properties of 5 structurally related Ru(II) complexes of [Ru(bpy)(2)L-1](2+) [Ru(bPY)(2)L (2)](2+), [Ru(bpy)(2)L-3](2+), [Ru(phen)(2)L-1](2+) and [Ru(phen)(2)L (2)](2+) (where bpy = 2,2'-bipyridine, phen=1,10-phenanthroline, L-1 =4-carboxylphenylimidado[4,5-f[1,10]phenanthroline, L-2= 3-carboxyl-4-hydroxylphenylimidado[4,5-f][1,10]phenanthroline, and L-3 = 3,4-dihydroxyphenylimidado[4,5-f][1,10]phenanthroline) have been studied in CH3CN/H2O (V/V, 1:1) by using oxalate as coreactant. The results indicated that the presence of hydroxyl in [Ru(bPY)(2)L (2)](2+), [Ru(bpy)(2)L-3](2+) and [Ru(phen)L-2 (2)](2+) 2+ effectively quenches ECL, and the other complexes exhibit comparable ECL efficiencies to [Ru(bpy)(3)](2+).