Macrocyclic Pyclen-Based Gd3+ Complex with High Relaxivity and pH Response
We report the synthesis and characterization of the macrocyclic ligand 2,2'-((2-(3,9-bis(carboxymethyl)-3,6,9-triaza-1(2,6)-pyridinacyclodecaphane-6-yl)ethyl)azanediyl)diacetic acid (H4L) and several of its complexes with lanthanide ions. The structure of the free ligand was determined using X-ray diffraction measurements. Two N atoms of the pyclen moiety in the trans position are protonated in the solid state, together with the exocyclic N atom and one of the carboxylate groups of the ligand. The relaxivity of the Gd3+ complex was found to increase from 6.7 mM-1 s-1 at pH 8.6 to 8.5 mM-1 s-1 below pH ≈ 6.0. Luminescence lifetime measurements recorded from H2O and D2O solutions of the Eu3+ …
CCDC 1884191: Experimental Crystal Structure Determination
Related Article: Juan C. Frías, José Soriano, Salvador Blasco, Enrique García-España, Aurora Rodríguez-Rodríguez, David Esteban-Gómez, Fabio Carniato, Mauro Botta, Carlos Platas-Iglesias, M. Teresa Albelda|2020|Inorg.Chem.|59|7306|doi:10.1021/acs.inorgchem.0c00690