A new method for the synthesis of polynuclear carboxylate complexes of technetium (II, III)

Abstract Acetates of actinides and their fission products were essential for the development of radiochemical industries using acetate precipitation technology. Despite this, the literature describes only the synthesis of species containing technetium in the oxidation state +3 and higher. New synthetic routes for the preparation of technetium +2.5 carboxylate polymer clusters using readily available technetium (IV) oxide as a precursor are developed in the present study. The crystal structure of synthesized complexes is studied by X-ray diffraction analysis (XRD) at different temperatures, and the coefficients of thermal expansion along the axes of the crystal lattice and in the direction of the polymer chain growth are determined. Matrix assisted laser desorption/ionization–time of flight (MALDI–ToF) mass-spectrometry showed stability of technetium carboxylates under conditions of laser ionization, which allows suggesting the possibility of technetium coatings deposition from the gas phase. Based on the obtained experimental results a reaction mechanism for the formation of tetracarboxylate oligomeric and polymer complexes of technetium was proposed. Stable oligomeric tetracarboxylate technetium clusters formed in acetic acid solutions can be used to create radiopharmaceuticals.