Identification of two types of complexes during association of pyrentetetrasulfonate with rare-earth ions using spectral-luminescent and kinetic measurements

To determine the nature of complexes interaction of pyrentetrasulfonate (PTS) and rare earth metal cations has been studied at 273 K in dimethylsulfoxide. Results of spectral-luminescent investigations (absorption spectra, curves of fluorescence extinguishing saturation and kinetic measurements) testify to the fact that in the process of PTS association with rare earth ions two types of complexes are formed. Outersphere and intrasphere complexes formed are in equilibrium. The investigations conducted permitted to determine the part of every complex. Thermodynamics of equilibrium and thermodynamical properties of the complexes, the structure of associates and fluorescence extinguishing mechanism have been studied