Synthesis of a mixed carboxylate–phosphinate AAZTA-like ligand and relaxometric characterization of its GdIII complex

The synthesis of the new polydentate ligand AAZ2A2PEt derived from the heptadentate polyaminocarboxylic ligand AAZTA (6-amino-6-methylperhydro-1,4-diazepine-N,N′,N″,N″-tetraacetic acid) in which two acetate groups were replaced by methyleneethylphosphinic pendant arms is reported. The relaxometric behavior of the corresponding mono-aquo GdIII complex was also investigated.