Two new dinuclear copper(II) complexes as efficient catalysts of luminol chemiluminescence

• Introducing new dinuclear copper(II) complexes as unique catalysts in luminol CL.
• The complexes act as an artificial peroxidase model at pH as low as 7.5 in water.
• The complexes act using dissolved O2, even in the absence of H2O2 at pH 12.
• The compounds containing SH group (l-cysteine and glutathione) inhibit the CL signal.
• A new CL probe for l-cysteine and glutathione in biological media.

The present study, introduces the beneficial catalyze effects of dinuclear copper(II) complexes on the luminol chemiluminescence (CL) reaction. Two new dinuclear copper(II) complexes ([Cu2(L)2(TAE)]X2 and [Cu2(L′)2(TAE)]X2), where TAE = tetraacetylethane; L = N,N′-dibenzyl ethylenediamine and L′ = N,N-dimethyl-N′-benzylethylenediamine; X = ClO4, have exhibited highly efficient catalytic activity of luminol CL as an artificial peroxidase model at pH as low as 7.5 in water in the presence of H2O2 and dissolved O2 even in the absence of H2O2 at elevated pH (∼12). The effects of the reactant concentrations and some amino acids on luminol CL were also investigated. Among them, l-cysteine (CySH) containing -SH group was observed to inhibit the CL signal of the luminol-H2O2-dinuclear copper(II) complex. A similar phenomenon also was observed for glutathione (GSH), which made CL probe of peroxidase-like dinuclear copper(II) complexes applicable for the determination of such compounds in biological media.

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