Luminescence Quenching of Binuclear Eu3+ and Tb3+tris(3-(2′-Pyridyl)-Pyrazolyl)Borate Complexes by Aromatic N-Nitrosamines Due to the Inner Filter Effect

It was shown that the emission intensity of (TpPyTb)2pma and (TpPyEu)2pma (TpPy– = tris(3-(2′-pyridyl)- pyrazolyl)borate, pma4– = tetraanion of pyromellitic acid) solutions decreases with the increasing concentration of N-nitrosamines with the luminescence quenching efficiency up to 92%. This quenching is due to the primary inner filter effect, i.e. the partial absorption of the exciting light by N-nitrosamines. It was suggested that the dependence of emission quenching efficiency of the complexes on the concentration of N-nitrosamines can potentially be used for estimation of their amount in solution by fluorescence spectroscopy.