Abstract
The reaction between DTPA (diethylenetriaminepenta-acetic acid)-anhydride and p-aminosalicylic acid (PAS) affords a novel ligand, [DTPA(PAS)2], able to form stable heterobimetallic complexes with Gd3+ and Fe3+ ions. The lanthanide ion occupies an internal coordination cage formed by three nitrogen atoms, two carboxylate and two carboxoamido groups of the ligand, whereas the outer salicylic moieties form stable chelate rings with FeIII ions. The stoichiometry of the resulting heterobimetallic complexes, established by measurements of water proton relaxation enhancement, is [(H2O)-Gd-DTPA(PAS)2]2-Fe(H2O)2 or [(H2O)-Gd-DTPA(PAS)2]3-Fe depending on the pH of the aqueous solution. The individual contributions to the observed relaxation enhancement from Gd3+ and Fe3+ paramagnetic ions have been clearly distinguished and analysed.
Lingua originale | Inglese |
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pagine (da-a) | 1315-1322 |
Numero di pagine | 8 |
Rivista | Spectrochimica Acta - Part A Molecular Spectroscopy |
Volume | 49 |
Numero di pubblicazione | 9 |
DOI | |
Stato di pubblicazione | Pubblicato - ago 1993 |
Pubblicato esternamente | Sì |