ИСТИНА

Technetium complexes in lower oxidation states are unstable and typically form with strong-field ligands, while complexes with weak-field ligands exist only in the presence of metal-metal bonds [1]. Thus, the chemistry of technetium complexes in oxidation states below 3+ with weak-field ligands can essentially be considered the chemistry of cluster compounds of this element. Research on the chemistry of technetium cluster compounds began in the early 1970s at the Institute of Physical Chemistry of the USSR Academy of Sciences after obtaining weighable quantities of this element from waste from nuclear fuel reprocessing [1]. One of the synthesis routes, used by the authors in [2], is based on the reduction of pertechnetate ions with molecular hydrogen under pressure in an autoclave. This method has the advantage of producing well-formed crystals free of foreign impurities. The autoclave method was initially developed for the synthesis of binuclear technetium clusters with [Tc2Cl8]3 anions and inorganic and organic cations [2]. The autoclave method for producing clusters has also proven convenient for the synthesis of more complex technetium clusters, including polynuclear ones. All currently known technetium clusters can be roughly divided into groups characterized by similar molecular and electronic structures. Acetic acid and acetic anhydride were also used as solvents in the study. Pink crystals of Tc2Ac5 were obtained.