Synthesis of new acyclic chelators and and their complexes with Cu²⁺, Ga³⁺, Y³⁺, and Bi³⁺

In this article, we present the synthesis and characterization of new acyclic pyridine-containing polyaminocarboxylate ligands H(4)aPyta and H(6)aPyha, which differ in structural rigidity and the number of chelating groups. Their abilities to form complexes with Cu2+, Ga3+, Y3+, and Bi3+ cations, as well as the stability of the complexes, were evaluated by potentiometric titration method, radiolabeling with the corresponding radionuclides, in vitro studies, mass spectrometry, and HPLC. The structures of the resulting complexes were determined using NMR spectroscopy and DFT calculations. The results obtained made it possible to evaluate the influence of the structural features of the complexes on their stability. The developed chelators H(4)aPyta and H(6)aPyha were proved to be promising for further research in the field of radiopharmaceuticals.