Double-Armed 18- and 21-Membered Macrocycles as Potential Chelators for Lead and Bismuth Radiopharmaceuticals.

With increasing clinical applications and interest in targeted alpha therapy, there is growing interest in developing alternative chelating agents for [Pb]Pb and [Bi]Bi that exhibit rapid radiolabeling kinetics and kinetic inertness. Herein we report the synthesis and detailed investigation of diacetate and dipicolinate 18- and 21-membered macrocyclic chelators BADA-18, BADA-21, BADPA-18, and BADPA-21 for the complexation of Pb and Bi ions with potential use in the preparation of radiopharmaceuticals. The formation of mononuclear complexes was established by using ESI-mass spectrometry, and their stability constants were determined by potentiometric titration.

Insights into Actinium Complexes with Tetraacetates─AcBATA versus AcDOTA: Thermodynamic, Structural, and Labeling Properties.

In the current research, we conducted a comparative study of the Ac complex with HDOTA and HBATA. The stability constants of the [AcBATA] and [AcDOTA] complexes were studied directly by extraction methods. We discovered that the thermodynamic properties of the [AcBATA] complex are superior to those of [AcDOTA].

Effect of the type of -substituent in the benzo-18-azacrown-6 compound on copper(II) chelation: complexation, radiolabeling, stability , and biodistribution .

In this work, we synthesized two new benzo-18-azacrown-6 ethers bearing picolinate and pyridine pendant arms and studied the copper complexes of these ligands, as well as those of an acetate analog. All considered ligands were capable of forming mono- and dinuclear complexes due to their large size and large number of donor sites. Among all forms of complexes, the coordination of cations inside the macrocycle has only been shown for the mononuclear form of the acetate complex, while out-cage coordination has been observed for other forms.

Novel Hybrid Benzoazacrown Ligand as a Chelator for Copper and Lead Cations: What Difference Does Pyridine Make.

A synthetic procedure for the synthesis of azacrown ethers with a combination of pendant arms has been developed and the synthesized ligand, characterized by various techniques, was studied. The prepared benzoazacrown ether with hybrid pendant arms and its complexes with copper and lead cations were studied in terms of biomedical applications. Similarly to a fully acetate analog, the new one binds both cations with close stability constants, despite the decrease in both constants.