Complexation of GdIII with tetra-p-tert-butylthiacalix[4]arenoic acid in micellar media

Abstract

The conditions for the formation of gadolinium(III) complexes possessing high relaxivity with various tetraacid stereoisomers based on p-tert-butylthiacalix[4]arene in micellar solutions of nonionic surfactants were established. The acid-base properties of individual isomers of the ligand were studied by pH-metric titration and UV spectroscopy. The composition and stability constants of the solubilized gadolinium(III) complexes with the obtained thiacalixarenes were determined using computer simulation of the NMR relaxation data. © 2009 Springer Science+Business Media, Inc.