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Tellurium Atom (tellurium + atom)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

A Combined Gas-Phase Electron Diffraction/Mass Spectrometric Study of the Sublimation Processes of TeBr4 and TeI4: The Molecular Structure of Tellurium Dibromide and Tellurium Diiodide

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 33 2008
Sergey A. Shlykov
Abstract The sublimation processes of TeBr4 at 471(5) K and TeI4 at 373(5) K were studied with a combined gas-phase electron diffraction and mass spectrometric technique (GED/MS). The mass spectra and the analysis of the GED intensities showed that a contribution of 40(3) mol-% TeBr2, 59(3) mol-% Br2, and 1 mol-% TeBr4 was formed in the vapor over TeBr4(s). Solid tellurium tetraiodide decomposes to form I2(g) and Te(s). A very small contribution of 3.3,±,2.1 mol-% of gaseous TeI2 was also determined by both GED and MS. The "metallic" Te accumulated in the solid phase vaporizes at above ca. 670 K as the predominately Te2 molcular species. Refinement of the GED intensities resulted in rg(Te,Br) = 2.480(5) Å and ,gBr,Te,Br = 99.0(6)° for TeBr2 and rg(Te,I) = 2.693(9) Å and ,g(I,Te,I) = 103.1(22)° for TeI2. The small contribution of TeBr4 observed in the mass spectra of the vapor over TeBr4 could not be observed in the GED data. Geometric parameters and vibrational frequencies for the tellurium dihalides TeX2 with X = F, Cl, Br, and I were calculated with B3LYP, MP2, CCSD, and CCSD(T) methods by using aug-cc-pVTZ basis sets and various core potentials for the tellurium atom. Bonding properties in tellurium dihalides are discussed on the basis of natural bond orbital analyses. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Extraction of shape-consistent spin-orbit pseudo-potential from an effective spin-orbit parameter and application to the tellurium atom

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2006
Emmanuel Fromager
Abstract A hybrid procedure to extract spin-orbit pseudo-potentials is proposed, taking information from both the orbital shape in the valence region and the atomic spin-orbit splitting. An effective atomic spin-orbit parameter is derived from a Dirac,Coulomb,Fock reference atomic calculation and is then used to extract the spin-orbit pseudo-potential. This method is tested for the ground-state configuration (5s25p4) of the tellurium atom. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source]

1-D-Tin(II) Phenylchalcogenolato Complexes ,1[Sn(EPh)2] (E = S, Se, Te) , Synthesis, Structures, Quantum Chemical Studies and Thermal Behaviour

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2010
Andreas Eichhöfer
Abstract A series of three 1-D-tin(II) phenylchalcogenolato complexes ,1[Sn(EPh)2] (E = S, Se, Te) were synthesized in yields > 80,% by reaction of SnCl2 with two equivalents of PhESiMe3 in organic solvents. In the crystal the molecules form two different types of one-dimensional chains. In ,1[Sn(SPh)2] the tin atoms are distorted trigonal pyramidal coordinated by sulfur atoms (two bonds within a monomer and one longer bond between neighbored monomers), while in ,1[Sn(EPh)2] (E = Se, Te) the tin atoms show contacts to two neighbored monomers leading to a fourfold coordination of the tin atoms by either selenium or tellurium atoms. The bond situation is discussed on the basis of density functional calculations. Thermal treatment mostly leads to the formation of the corresponding phase pure tin(II) chalcogenides however sublimation plays an increasing role ongoing from the tellurolato to the thiolato complex especially for the use of vacuum conditions. The investigation of the volatile cleavage products reveals the occurence of more complex reactions in the gas phase than the formal stoichiometric cleavage of EPh2 (E = S, Se, Te) with formation of SnE. [source]

Octa- O -bis-(R,R)-Tartarate Ditellurane (SAS),a Novel Bioactive Organotellurium(IV) Compound: Synthesis, Characterization, and Protease Inhibitory Activity,

CHEMMEDCHEM, Issue 11 2007
Sigal Yosef Dr.
Abstract Octa-O-bis-(R,R)-Tartarate Ditellurane (SAS) is a new TeIV compound, comprised of two tellurium atoms, each liganded by four oxygen atoms from two carboxylates and two alkoxides of two tartaric acids. Unlike many other TeIV compounds, SAS was highly stable in aqueous solution. It interacted with thiols to form an unstable Te(SR)4 product. The product of the interaction of SAS with cysteine was isolated and characterized by mass spectroscopy and elemental analysis. SAS selectively inactivated cysteine proteases, but it did not inactivate other families of proteolytic enzymes. It displayed selectivity towards the cysteine protease cathepsin,B, a human enzyme of pharmaceutical interest, with a second order rate constant ki/Ki=5900,M,1,s,1. [source]