Structures and relative energies of binuclear iron-manganese complexes with the phosphine ligand L, which exist in vinylidene Cp(CO)(L)MnFe(μ-C=CHPh)(CO)4 (2) and benzylidene ketene η4-{C[Mn(CO)(L)Cp]∙ ∙(CO)CHPh}Fe(CO)3 (3) forms are calculated by the B3LYP density functional method. Four isomers with different positions of ligand L relative to the phenyl ring (conformers a and b) and the substituent Ph relative to the С=С bond (conformers E and Z) are considered for each form and their relative stability is determined. It is shown that all isomers of 2 have approximately the same energy (within 4 kcal/mol) whereas the energies of isomers of 3 differ within 21 kcal/mol. Isomer 3Ea in which the PPh3 ligand contacts with the phenyl substituent of the vinylidene group is most energetically favorable. It is found that with an increase in the L ligand size in the order PH3 < PH2Ph < PHPh2 < PPh3 the Mn–P bond length increases to 2.37 Å in the most stable isomer of form 3 and to 2.43 Å in the isomers of 2 and three conformers of 3. A more substantial increase in the Mn–P bond length in complexes 2 and 3 correlates with their lower stability as compared to isomer Ea of 3, which is consistent with experimental data on the presence of only one conformer 3Ea in solution.
The influence of tritium aerosol transport on radioactive contamination on the territory of the Krasnoyarsk region influenced by the mining–chemical combine of the Rosatom State Corporation was studied. Snow cover, foliage, and needles collected at various distances from the mining–chemical combine were selected as the object of this study. A new methodology of liquid extraction from plant material (leaves and needles) was worked out. As a result, the maximal concentrations of tritium (15 kBk/m3 in snow, 11 and 15 Bk/m2 for leaves and pine-tree needles, respectively) were determined. However, the results obtained are not anomalous. Consequently, contamination with tritium may not be accounted for entirely due to the low concentrations.