Diimine ligand as a novel chemiluminescence enhancer of luminol-containing compounds

A series of diimine ligands (DLs) have been synthesized and evaluated for their non-enzymatic chemiluminescence (CL) enhancement of isoluminol or luminol-containing compounds. Of the DLs, N,N’-bis(m-hydroxylbenzylidene)propylenediamine (DL 10) was found to greatly enhance their CLs approximately 40 folds for isoluminol, 10 folds for luminol and 6 folds for a luminol-containing polymer. The CL enhancement of the compounds was observed in the presence of CH3CN, H2O2, tetra-n-propylammonium hydroxide (TPA), and Fe (III) ion. The possible mechanism of this CL enhancement was discussed on the basis of the chelate formation of the ligand and the metal ions.