Investigations into the inhibition of luminol chemiluminescence by some novel metal complexes

In this study, we prepared two different type complex groups. One of them is based on Schiff base (A¹, A² and A³) Cd(II) complexes, another one is β-blockers (acebutolol (ACE), atenolol (ATE) and propranolol (PRO)) Cu(II) complexes. The ligands and their metal complexes were characterized by elemental analyses, mass spectra, ¹H(¹³C) NMR spectra, FT-IR, UV-vis, conductivity measurements and thermal analysis studies. Protonation constants of the ligands and stability constants of their complexes were determined by potentiometric titration method at 25.00±0.02 °C under nitrogen atmosphere and ionic strength of 0.10 M sodium perchlorate. For the Schiff bases, the solvent was 50% DMSO-water; for the β-blockers, it was 50% methanol-water media. The effects of these properties on the observed inhibition of chemiluminescence and the analytical implications of the results are also discussed. Two sets of novel coordination compounds were found to inhibit the intense chemiluminescence reaction in DMSO solution between luminol and dioxygen in the presence of a strong base.