Rigid and Compact Binuclear Bis‐hydrated Gd‐complexes as High Relaxivity MRI Agents. Issue 46 (2nd July 2021)

• Record Type: Journal Article
• Authors: Leone, Loredana; Guarnieri, Luca; Martinelli, Jonathan; Sisti, Massimo; Penoni, Andrea; Botta, Mauro; Tei, Lorenzo
• Is Part Of: Chemistry. Volume 27:Issue 46(2021)
• Page Start: 11811
• Page End: 11817
• Publication Date: 2021-07-02
• Subjects: binuclear complexes -- contrast agents -- gadolinium -- macrocycles -- relaxometry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202101701
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The first binuclear Gd‐complex of the 12‐membered pyridine‐based polyaminocarboxylate macrocyclic ligand PCTA was synthesized by C−C connection of the pyridine units through two different synthetic procedures. A dimeric AAZTA‐ligand was also synthesized with the aim to compare the relaxometric results or the two ditopic Gd‐complexes. Thus, the 1 H relaxometric study on [Gd2 PCTA2 (H2 O)4 ] and on [Gd2 AAZTA2 (H2 O)4 ] 2− highlighted the remarkable rigidity and compactness of the two binuclear complexes, which results in molar relaxivities (per Gd), at 1.5 T and 298 K of ca. 12–12.6 mM −1 s −1 with an increase of ca. 80 % at 1.5 T and 298 K (+70 % at 310 K) with respect to the corresponding mononuclear complexes. Abstract : Two novel binuclear PCTA2 and AAZTA2 ligands were synthesized with a multistep process. Their Gd III ‐complexes results in molecular relaxivities at 1.5 T and 298 K of ca. 24–25 mM −1 s −1 thanks to the rigidity and compactness of the ligands. These values are remarkably higher that those found for the corresponding mononuclear complexes.