Synthesis and Relaxivity of α-Oxo-γ-Ethoxycarbonylbutanoic Acid Thiosemicarbazone Rare Earth Complexes

• Published in: Synthesis and reactivity in inorganic and metal-organic chemistry 2002-11, Vol.32 (6), p.1059-1069
• Main Authors: Yang, Zheng-Yin, Yang, Ru-Dong
• Format: Article
• Language: English
• ISSN: 0094-5714; 1532-2440
• DOI: 10.1081/SIM-120013020

The rare earth metal complexes of α -oxo- γ -ethoxy carbonylbutanoic acid thiosemicarbazone (HEAT) have been synthesized in the template reaction when LnCl 3 ·nH 2 O was added to the system dissolved α -oxopentanedioic acid and thiosemicarbazide in anhydrous ethanol and refluxed on a water bath. Although α -oxopentanedioic acid thiosemicarbazone (H 2 PAT) can be synthesized in the system without LnCl 3 ·nH 2 O, HEAT cannot be formed under analogous conditions. This proves that the compounds LnCl >3 ·nH 2 O have a catalytic effect on the esterification reaction. The composition and nature of the complexes are characterized by elemental analyses, thermal analyses, UV, IR, and 1 H NMR spectra. In addition, the relaxivity (R 1 ) of the Gd-complex has been determined by the INVLNC.Au program using inversion recovery pulse sequences, R 1 =8.10 mmol·L −1 ·s −1 .