Abstract The crystal structure of the complex (α R ,6 R )-Na[Gd(H 2 O)-AAZTA-C 2 H 4 COOBn]·3H 2 O·EtOH was determined by single crystal X-ray diffraction; the complex represents a bifunctional derivative of Gd-AAZTA, previously reported as original scaffold for the development of efficient contrast agents for MRI. The Gd(III) ion is nine coordinated with three nitrogens, five carboxylate oxygens and
Variation of water exchange dynamics with ligand structure and stereochemistry in lanthanide complexes based on 1,4-diazepine derivatives
作者:Elisa M. Elemento、David Parker、Silvio Aime、Eliana Gianolio、Luciano Lattuada
DOI:10.1039/b818445c
日期:——
Complexes of Gd, Eu and Yb(III) have been prepared with a series of heptadentate ligands related to the parent complex AAZTA, based on the 6-methyl-6-aminoperhydrodiazepine moiety. For (RR) and (RS)-diastereoisomers of a di-glutarate ligand, solution NMR studies revealed the presence of two major species that undergo water exchange rates at Gd differing by a factor of six. Comparison of solution hydration states for Eu(III) complexes reveals that each complex possesses two bound water molecules. The absence of a good correlation of 1H NMR pseudo-contact shifts for Eu and Yb analogues is suggested to arise from a change in hydration state between Eu and Yb.