Relevance of Oxocyclam from Palladium(II) Coordination to Radiopharmaceutical Development
Abstract
We provide a comprehensive study of the coordination of with palladium(II), including presentation of a novel bifunctional analogue, bearing an aniline pendant. The complexation of palladium(II) with was examined by various techniques, including NMR analysis and potentiometric titrations which revealed that the Pd(II) complex can adopt different configurations such as -I and -III. In addition, forms a thermodynamically stable palladium(II) complex, the stabilization being attributed to the deprotonation of the amide function. The crystal structures of [Pd(H)] and [Pd()] were obtained, revealing the structural details previously anticipated, including, in the second case, the presence of the proton on the carbonyl oxygen atom. Additionally, the study explored the redox behavior of the Pd(II)- complex through reduction and oxidation voltammograms at different pH values. Successful Pd-labeling of and at pH 3.5 demonstrated high labeling efficiencies, whatever the species formed. The stability of the radiocomplexes was assessed and moderate transchelation toward EDTA was observed. Overall, displayed favorable properties for Pd(II) coordination and radiolabeling, suggesting its potential as a chelating agent for this metal in palladium-based applications.