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991.
Two neutral group 15-pentaazides dmap-As(N(3))(5) (1) and dmap-Sb(N(3))(5) (2) were synthesized and structurally characterized for the first time (dmap = 4-dimethylaminopyridine). Base-stabilization was confirmed to be very suitable for the kinetic stabilization of highly explosive covalent main group polyazides. 相似文献
992.
Information on the electronic structure of a molecule and its chemical bonds is encoded in the molecular normal vibrational modes. However, normal vibrational modes result from a coupling of local vibrational modes, which means that only the latter can provide detailed insight into bonding and other structural features. In this work, it is proven that the adiabatic internal coordinate vibrational modes of Konkoli and Cremer [Int. J. Quantum Chem. 67, 29 (1998)] represent a unique set of local modes that is directly related to the normal vibrational modes. The missing link between these two sets of modes are the compliance constants of Decius, which turn out to be the reciprocals of the local mode force constants of Konkoli and Cremer. Using the compliance constants matrix, the local mode frequencies of any molecule can be converted into its normal mode frequencies with the help of an adiabatic connection scheme that defines the coupling of the local modes in terms of coupling frequencies and reveals how avoided crossings between the local modes lead to changes in the character of the normal modes. 相似文献
993.
Herbert Meier Michael Schmidt Axel Mayer Dieter Schollmeyer Bernhard Beile 《Journal of heterocyclic chemistry》2012,49(3):516-520
The reaction of benzothiete ( 1 ) and the bicyclic alkenes 5 , 7 , 9 , or 12 shows a very high π side selectivity (de > 95%) in the formation of the polycyclic thiopyrans 6 , 8 , 10 , 11 , 13 , and 14 . 相似文献
994.
Prof. Dr. Stephan Schulz Sarah Schmidt Dieter Bläser Christoph Wölper 《无机化学与普通化学杂志》2012,638(11):1705-1710
Zincocene Cp*2Zn reacts with carbodiimides C(NR)2 with insertion into the Zn–Cp* bond and formation of [(Cp*C(NR)2]2Zn [R = Et ( 1 ), iPr ( 2 ), Cy ( 3 )]. In addition, the reaction of Cp*2Zn with CS2 under dry conditions gives (Cp*CS2)2Zn ( 4 ), whereas in the presence of a small amount of water [Zn4(μ4‐O)(S2CCp*)6] ( 5 ) is obtained. Compounds 1 – 4 were characterized by NMR (1H, 13C) and IR spectroscopy as well as elemental analysis and single‐crystal X‐ray diffraction ( 2 – 4 , 5 of poor quality). The solid‐state structure of 5 is comparable to the carboxylate complex previously obtained from the reaction of Cp*2Zn with CO2. 相似文献
995.
Based on the new binuclear gold(I) complex [(AuCl)2(L1)] (1) (L1?=?2,3-bis(diphenylphosphino)maleic anhydride) four new polynuclear compounds were synthesized by reactions of 1 with E(SiMe3)2 (E?=?S, Se). During the formation of these new compounds the initial ligand L1 undergoes various transformations (e.g. substitution, hydration or hydrogenation) leading to the new ligands: trans-2,3-bis(diphenylphosphino)succinic anhydride (L2), 2-diphenylphosphino-3-mercapto-maleic anhydride anion (L3), 2-diphenylphosphino-3-selenolato-maleic anhydride anion (L4) and 2,3-bis(diphenylphosphino)succinic acid (L5). In case of using the sulfur species S(SiMe3)2 a pentanuclear cluster, [Au5(PPh2)3(L3)2] (2), and a 24-nuclear cluster, [Au24S6(PPh2)4(L3)8] (3), could be obtained. With Se(SiMe3)2 the binuclear complex, [(AuCl)2(L2)] (4), and the dodecanuclear cluster, [Au12Se4(L4)4(L5)2] (5), were yielded. 相似文献
996.
Weiss VU Subirats X Pickl-Herk A Bilek G Winkler W Kumar M Allmaier G Blaas D Kenndler E 《Electrophoresis》2012,33(12):1833-1841
During infection, enteroviruses, such as human rhinoviruses (HRVs), convert from the native, infective form with a sedimentation coefficient of 150S to empty subviral particles sedimenting at 80S (B particles). B particles lack viral capsid protein 4 (VP4) and the single-stranded RNA genome. On the way to this end stage, a metastable intermediate particle is observed in the cell early after infection. This subviral A particle still contains the RNA but lacks VP4 and sediments at 135S. Native (150S) HRV serotype 2 (HRV2) as well as its empty (80S) capsid have been well characterized by capillary electrophoresis. In the present paper, we demonstrate separation of at least two forms of subviral A particles on the midway between native virions and empty 80S capsids by CE. For one of these intermediates, we established a reproducible way for its preparation and characterized this particle in terms of its electrophoretic mobility and its appearance in transmission electron microscopy (TEM). Furthermore, the conversion of this intermediate to 80S particles was investigated. Gas-phase electrophoretic mobility molecular analysis (GEMMA) yielded additional insights into sample composition. More data on particle characterization including its protein composition and RNA content (for unambiguous identification of the detected intermediate as subviral A particle) will be presented in the second part of the publication. 相似文献
997.
Based on the normalized elimination of the small component relativistic formalism, a new approach to the calculation of hyperfine structure parameters of paramagnetic molecules is developed and implemented. The new method is tested in the calculation of the isotropic hyperfine structure constant for a series of open-shell molecules containing mercury. The results of calculations carried out in connection with ab initio methods of increasing complexity demonstrate the high accuracy of the formalism developed. In view of its computational simplicity, the new approach provides the basis for an efficient and accurate calculation of the HFS parameters of large molecules. 相似文献
998.
The existing combinatorial methods for iso-surface computation are efficient for pure visualization purposes, but it is known that the resulting iso-surfaces can have holes, and topological problems like missing or wrong connectivity can appear. To avoid such problems, we introduce a graph-theoretical method for the computation of iso-surfaces on cuboid meshes in ℝ3. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
999.
The reactions of CuCl and tBuTeSiMe3 in the presence of phosphine ligands result in the formation of four new Cu/Te cluster complexes, [Cu18Te6(TetBu)6(PPh2Et)7], [Cu19Te6(TetBu)7(PEt3)8], [Cu27Te15(PiPr2Me)12] and [Cu58Te32(PtBu2
nBu)14], which have been structurally characterized by single crystal structural analysis. The former two clusters show a layer-type tellurium frameworks in which the copper atoms are asymmetrically spread. The latter two clusters possess a tellurium framework in a body-centered Te14-Frank-Kasper polyhedron or a Te28 polyhedron with four interstitial tellurium atoms and belong to mixed-valence Cu/Te compounds. 相似文献
1000.
Alexander V. Virovets Irina V. Kalinina Vladimir P. Fedin Dieter Fenske 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e589-e590
During an investigation of the W/Te/Br2 system, we prepared crystals of the title compound, C20H40N4S8Te, from acetonitrile solution by slow addition of diethyl ether. It appeared to be a new tetragonal modification. The calculated density of the tetragonal modification (1.513 Mg m?3) is slightly greater than found for the known orthorhombic modification (1.46 Mg m?3). The bond distances and angles are practically the same. 相似文献