New titanium(IV) coordination compounds with 2-hydroxybenzyl alcohol derivatives used in the preparation of ultra-high molecular weight polyethylene

Russian Chemical Bulletin - A reaction of 2,4-bis(α,α-dimethylbenzyl)phenol with TiCl2(ОPri)2 and Ti(ОPri)4 was used to obtain the coordination compounds...     

Quantum yield spectra of vanadium in tetrahedral [VO4]3− complexes

Conclusions Studies of VL_2,3 quantum yield spectra and analysis of theoretical and experimental data were used to give information on the processes proceeding during the emission and absorption of the X-ray VL-radiation. It is very probable that the X-ray L₃-absorption processes in compounds where the 3d-metal has the highest valence proceed in the presence of an additional electron on one of the vacant orbitals (for tetrahedral complexes on the 2e-MO). This assumption can confirm the hypothesis on the reemissional transitions and explain the energy divergence between the VL-emission and absorption spectra.Institute of Physics of Metals, Ural Branch Academy Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 1, pp. 81–86, January–February, 1988.     

Electronic structure and chemical binding in high-temperature semiconductors. Theoretical and experimental investigations

Chemical Institute and Institute for the Physics of Metals, Urals Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 5, pp. 134–147, September–October, 1988.     

Plasma Radiation Source on the Basis of the Gas Puff with Outer Plasma Shell in the Circuit of a Mega-Ampere Load Current Doubler

Russian Physics Journal - Characteristics of Z-pinch plasma radiation in the form of a double shell neon gas puff with outer plasma shell are investigated in the microsecond implosion mode....     

Olefin polymerization behavior of titanium(IV) alkoxo complexes with fluorinated diolate ligands: The impact of the chelate ring size and the nature of organoaluminum compounds

Titanium(IV) coordination compounds are effectively used as precatalysts for ethylene polymerization and copolymerization with other olefins. New titanium(IV) complexes 3b – d with ligands containing two diphenylcarbinol fragments linked by the perfluorinated hydrocarbon units –CF₂– or –C₂F₄– were synthesized. The structures of complexes 3b and 3d were determined by X-ray diffraction. Titanium atoms in 3b have a distorted trigonal-bipyramidal coordination environment while spiro-complex 3d is characterized by tetrahedral molecular geometry. The catalytic behavior of complexes activated by mixtures of Bu₂Mg and alkylaluminium chlorides from among Me₂AlCl, Et₂AlCl, EtAlCl₂, and Et₃Al₂Cl₃ were studied. The resulting catalytic systems catalyze ethylene polymerization to afford ultra-high molecular weight polyethylene, suitable for modern processing methods, and the solvent-free solid state formation of super high-strength (1.37–2.75 GPa) and high-modulus (up to 138 GPa) oriented film tapes. The same catalytic systems catalyze ethylene copolymerization with 1-hexene to afford high molecular weight semicrystalline elastomeric polymers containing up to 20% of comonomer units.     

Experiments with wire arrays at a submicrosecond current risetime

Experiments with wire arrays of the z-pinch geometry consisting of copper and tungsten wires of length up to 8 cm have been performed on the GIT-12 generator at a current pulse risetime of ∼300 ns and ∼1 μs. These modes were compared as to the efficiency of the wire array implosion. For the 300-ns pulse a ∼5-nH/cm change in inductance has been achieved. It has been demonstrated that the lifetime of the plasma precursor is proportional to the current risetime. Institute of High Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 81–90, December, 1999.     

Interpretation of ESCA spectra for non-stoichiometric titanium carbides on the basis of MO—LCAO calculations

The results of electron structure calculations for the single clusters TiC₆^20?, TiC₅□^16?, TiC₄□₂^12?, TiC3□3^8?, TiC₅□^16.64?, TiC₄□₂^13.32?; and double clusters Ti₂C₁₀^32?, Ti₂C₈□₂^24?, Ti₂C₁₀□^32.72? and Ti₂C₈□₂^24.80? by the semi-empirical Mulliken—Wolfsberg—Helmholtz method with self-consistency of charges and configurations are given. The data obtained are compared with measurements of the Ti 2p-level binding energies and X-ray photoelectron valence band spectra for TiC_x(x = 0.86–0.97). The variation of the metal atom charge in the limits of the homogeneity region for TiC and the appearance of this effect as a chemical shift of the Ti 2p-level are discussed. A special set of cluster calculations was performed to check the possibility of Ti valency variation in the homogeneity region of TiC_x.     

X-ray emission spectra and electronic structure of VO,VN, VC

The experimental K_β5 and L_α emission spectra for vanadium and K_α spectra for nonmetal are studied for vanadium monoxide, nitride and carbide. Using the spectra unfolding the experimental molecular orbital diagrams have been obtained. By the semiempirical Mulliken-Wolfsberg-Helmholz method with the self-consistency on charges and configurations the calculations of electronic structure of clusters [VO₆]^10?, [VN₆]^15? and [VC₆]^20? have been carried out. The results of calculations are compared with the X-ray data. The effects of chemical bonding and charge densities on metal atoms in VO, VN, VC are discussed.