Novel organosilicon betaines

The structure of organosilicon betaines R₃P⁺CMe₂SiMe₂S^– (R = Ph and Me₂N) was determined by X-ray diffraction analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 339–340, February, 1994.     

Shielding constants of tin 119Sn nuclei

A number of organotin compounds have been studied using the heteronuclear double resonance H¹-{Sn¹¹⁹}. The tin chemical shifts have been tabulated and discussed on the basis of the concept of electronegativity. The highfield displacement is found attributable to the filling of the 5d-orbitals of the tin atom.     

Fine tuning the anion binding properties of 2,6-diamidopyridine dipyrromethane hybrid macrocycles

The synthesis, characterization, and anion-binding properties of a series of 2,6-diamidopyridine dipyrromethane hybrid macrocycles is presented. As part of this work, a new method for effecting the oxidation of dipyrromethane-based macrocycles in organic solvents has been developed. The macrocyclic frameworks presented here stand out because of their ease of synthesis and tunable anion-binding properties. Evidence for anion binding was obtained from UV-vis spectroscopic titrations carried out in acetonitrile. The results clearly indicate that by changing the flexibility, cavity size, and directionality of anion-binding moieties in the macrocyclic framework the anion selectivity may be changed dramatically. These results are in accord with density functional theory molecular modeling calculations performed on one member of the series.     

Indenyl and fluorenyl transition metal complexes: XV.Reactions of 1,1-dimethylindene,spirocyclopropane-1,1-indene,and spirocyclopropane-9,9-fluorene with L3M(CO)3 (L = NH3, Py; M = Cr,Mo, W)

Reaction of indene, 1,1-dimethylindene, spirocyclopropane-1,1-indene, and spirocyclopropane-9,9-fluorene with Py₃M(CO)₃/BF₃ · OEt₂ (M = Cr, Mo, W) involves two competing processes: (i) the formation of the ₆-arene complexes (A) and (ii) the oxidative addition at the C(1)R and C(9)R bonds (R = alkyl) with the formation of chelated σ,π-complex (B). The reaction pathway (A or B) is determined both by the metal and the ligand.     

Extraction of actinides with heterocyclic dicarboxamides

Extraction of actinides from aqueous nitric acid by three different heterocyclic dicarboxamides (2,6-pyridinedicarboxamide, 2,2′-bipyridine-6,6′-dicarboxamide and 1,10-phenanthroline-2,9-dicarboxamides) was studied. It was shown that all studied ligands extract actinides at different oxidation states (U(VI), Np(V), Pu(IV), Am(III), Cm(III)) from acidic solutions. All studied diamides extract Am(III) better than Cm(III). Et(pHexPh)ClPhen contains electron-withdrawing chlorine atoms at the positions 4 and 7 of the phenanthroline moiety (SF_Am/Cm = 4–6) and possesses the highest separation factor Am(III)/Cm(III). The studied ligands possess high extraction ability to all actinides present in HLW and therefore they could be used for simultaneous extraction of actinides in the GANEX-type process.     

Ion pairs formed in metallocene-based systems by the “double activation” mechanism and their catalytic activity

The DFT method is used to study the interaction between metallocene catalyst precursors used in ethylene and propylene polymerization and two molecules of the Al-containing cocatalyst Al(C₆F₅)₃. The participation of two Al centers in metallocene activation accounts for the catalytic activity and other properties of the catalytic systems. Two energy parameters characterizing the number of active sites and the polymerization rate per site are calculated. Published in Russian in Kinetika i Kataliz, 2006, Vol. 47, No. 2, pp. 215–222. The article was translated by the authors.