Search

Technetium(I) tetracarbonyl complexes with diethyldithiocarbamate and methylxanthate ligands [TcL(CO)(4)] (L = S(2)CNEt(2) and S(2)COMe) were prepared. Conditions required for the formation of these complexes were found. The crystal and molecular structure of the xanthate complex was determined by single-crystal X-ray diffraction. [Tc(S(2)CNEt(2))(CO)(4)] undergoes decarbonylation both in solution and in the course of vacuum sublimation with the formation of a dimer [Tc(S(2)CNEt(2))(CO)(3)](2) whose structure was determined by single-crystal X-ray diffraction. In donor solvents, [Tc(S(2)CNEt(2))(CO)(4)] and [Tc(S(2)COMe)(CO)(4)] undergo decarbonylation with the formation of tricarbonyl solvates [TcL(CO)(3)(Sol)]. The crystal structure of the pyridine solvate [Tc(S(2)CNEt(2))(CO)(3)(py)], chosen as an example, was determined by single-crystal X-ray diffraction. The possibility of using bidentate S-donor acidic ligands for tethering the tetracarbonyltechnetium fragment to biomolecules was examined.

Technetium carbonyl complexes [TcBr(CO)5], [TcI(CO)5], [TcX(CO)3]4 (X = Cl, Br, I), [TcBr(CO)3en] (en = ethylenediamine), [Tc(RCOCHCOR′)(CO)3(Et2NH)] [R = CH3 or C(CH3)3, R′ = CF3], Tc2(CO)10, and [Tc(C5H5)(CO)3] were tested as starting compounds for chemical vapor deposition of technetium coatings. The conditions of deposition of technetium coatings were determined, and the deposition yields were evaluated.

The microstructure, chemical and phase composition, and corrosion resistance of coatings deposited by thermolysis of vapors of volatile technetium carbonyl compounds on a titanium support are studied. The relationship between the nature of the starting compound, conditions of the heat treatment of the coatings, and their chemical and phase composition and corrosion resistance is analyzed. Vacuum annealing at a high temperature (no less than 900°C) is the necessary condition for preparing corrosion-resistant coatings. The highest corrosion resistance is attained at low ( 15%) carbon content of the coating. Some samples are not inferior to dense technetium foil in the corrosion resistance. Ways of further improvement of the deposition process are outlined.

Synthetic and natural uranium oxides UOx (2≦×≦3) have been studied with X-ray photoelectron spectroscopy (XPS) to determine the phase composition and content of uranium ions in uraninites with a varying degree of oxidation. A strong hybridization of U6p and O2s orbitals has been found which permits a quantitative assessment of the U-O bond lengths. The values of such bonds in some substances have been found to be smaller than those in synthetic U(VI) oxide. The oxides U2O5 and U3O8 contain two types of uranium ions with a varying degree of oxidation.

Dimerization energies of trioctylammonium halides in carbon tetrachloride solution, associated as a result of dipole-dipole interaction, were calculated from the infrared absorption spectra. The values obtained were 5, 4, and 1.5 kcal/mole for the chloride, bromide, and iodide, respectively. The calculation showed that the dimers of these salts are contact dimers.