Vol 476, No 1 (2017)

The reactions of commercial polychlorobiphenyl mixtures of Sovol and Trikhlorbifenil brands (Russia) with sodium methoxide were studied in dimethyl sulfoxide and methanol. It was shown for the first time that Sovol congeners are exhaustively converted, without formation of potentially toxic products, in the reaction with alkali metal alkoxide based on a monobasic aliphatic alcohol. This process is a stage of chemical pretreatment of polychlorobiphenyls subject to destruction for the subsequent microbiological mineralization of the new derivatives.

Computational modeling (DFT UB3LYP*/6-311++G(d,p)) of mixed-ligand complexes of cobalt bis(chelate)s with N,N-diphenyl-diiminophenoxazine has been performed. It has been shown that variation of the electron-withdrawing and bulky substituents in the diketonate and azomethine moieties has a significant impact on the stability of the resulting adducts and on the energy difference between their low-spin and high-spin states. The compounds capable of exhibiting valence tautomeric properties have been revealed.

Sulfate-substituted hydroxyapatite materials with a degree of substitution of up to 20 mol % (Ca₁₀(PO₄)_{(6 – 0.06x)}(SO₄)_0.09x(OH)₂, x = 0, 0.1, 0.5, 1, 5, 10, and 20) were synthesized. For substitutions of 0, 0.1, 0.5, and 1 mol %, a single-phase material with the apatite structure is formed. On further increase in the concentration of SO₄²⁻ groups up to 20 mol %, a second phase, CaSO₄, is formed; the amount of this phase increases for higher degrees of substitution. The unit cell parameters of hydroxyapatite-based materials change slightly upon the replacement of phosphate groups by sulfate groups: the parameter a tends to increase, while c tends to decrease. The introduction of sulfate groups results in decreasing particle size.