International Journal of Quantum Chemistry

Cover image for Vol. 114 Issue 4

15 February 2014

Volume 114, Issue 4

Pages i–iv, 241–303

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor
    1. You have free access to this content
      Cover Image, Volume 114, Issue 4 (pages i–ii)

      Article first published online: 2 JAN 2014 | DOI: 10.1002/qua.24602

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      The reaction of trifluoromethyl thioamide with trimethylphosphite is schematically shown on the cover. This reaction proceeds via a three-member intermediate, for which the decomposition yields the short-lived dimethylaminotrifluoromethylcarbene. The latter reacts with the excess of trimethylphosphite, giving the corresponding phosphorus ylide. This is only one example of the series of reactions of (perfluoro)alkyl (thio)amides with trimethylphosphine, trimethyl phosphite, or tris(dimethylamino)phosphine. Alexander B. Rozhenko et al. on page 241 use different quantum chemistry approaches to theoretically study their reaction pathways and thermodynamics.

    2. You have free access to this content
      Inside Cover, Volume 114, Issue 4 (pages iii–iv)

      Article first published online: 2 JAN 2014 | DOI: 10.1002/qua.24603

      Thumbnail image of graphical abstract

      Using the reaction-relevant twodimensional potential energy surface, an accurate reaction-pathway mapping, and ab inito molecular dynamics (AIMD), Maoping Pu and Timofei Privalov on page 289 show that CO2 capture by P(tBu)3 and B(C6F5)3 species has many nearly degenerate reaction routes. The magnitude and timescales of the conformational dynamics of this pair at room temperature and the typical CO2 binding energy in van der Waals complexes are used to probe an interaction of CO2 with P(tBu)3 and B(C6F5)3 with AIMD simulations. The cover art merges snapshots from lowtemperature simulations. Optimized geometries of random snapshots are used to obtain a group of the most stable conformations with diverse positioning and orientation of CO2.

  2. Full Papers

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor
    1. Intermediate carbene formation in the reaction of thioamides with phosphorus (III) derivatives: Quantum chemical investigation (pages 241–248)

      Alexander B. Rozhenko, Sergiy S. Mykhaylychenko, Nadiya V. Pikun, Yuriy G. Shermolovich and Jerzy Leszczynski

      Article first published online: 8 OCT 2013 | DOI: 10.1002/qua.24546

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      Theoretical methods are valuable for the study of highly reactive intermediaries in reactions. This work studies the mechanism of the recently reported reaction of (perfluoro)alkyl (thio)amides with phosphorus(III) derivatives. The formation of short-lived perfluoroalkyl carbenes is predicted as a probable intermediate in the reaction of perfluoroalkyl thioamides with trimethyl phosphites and tris(dimethylamino)phosphine. Adding the second mole of the phosphorus(III) derivative to the carbene is thermodynamically favored. The formed phosphorus ylides undergo further transformations.

    2. A density functional theory study on the catalytic mechanism of hydroxycinnamoyl-CoA hydratase-lyase (pages 249–254)

      Guangcai Ma, Yulin Li, Lixin Wei, Yongjun Liu and Chengbu Liu

      Article first published online: 23 SEP 2013 | DOI: 10.1002/qua.24551

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      Vanillin, a leading flavoring compound used in the food industry, is synthesized from the biologically abundant ferulic acid through twostep enzyme catalysis. This work examines the catalysis mechanism of the responsible enzyme in the second step. The second step is in turn found to consist of two constituent steps. This work is expected lend insight into the precise nature of reactants responsible for this commercially important reaction.

    3. Theoretical determination of the differential polarizability and anisotropy of alkaline earth oxide nanoclusters (BeO)n [n = 2–9]: The basis set and electron correlation effects (pages 255–260)

      Mojtaba Alipour

      Article first published online: 30 SEP 2013 | DOI: 10.1002/qua.24552

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      BeO is a rare oxide often used in high-performance ceramic materials, with applications in atomic energy, aviations, and the metallurgical industry. The mean dipole polarizabilities, differential polarizabilities, and anisotropies of beryllium oxide nanoclusters (BeO)n [n = 2–9] can be computed and understood using density functional theory and ab initio methods. A careful consideration of the effects of electron correlation correction and basis set selection on the dipole polarizabilities is paramount to obtaining an acceptable accuracy.

    4. Effect of molecular vibrations on the MD/QC-simulated absorption spectra (pages 261–270)

      Andrzej Eilmes

      Article first published online: 30 SEP 2013 | DOI: 10.1002/qua.24553

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      Simulated absorption spectra are calculated from time-dependent density functional theory results averaged over a series of molecular geometries retrieved from Born–Oppenheimer molecular dynamics trajectories. For constant energy simulations of small systems, bond length distributions and absorption spectra exhibit a bimodal bandshape as a result of the classical treatment of vibrations. For corresponding trajectories of larger systems or simulations in the NVT ensemble, calculated absorption bands are symmetric, while still deviating from the results of Franck–Condon analysis.

    5. Total scattering cross sections for ethylene by electron impact for incident electron energies from 1 to 2000 eV (pages 271–277)

      Rahla Naghma and Bobby Antony

      Article first published online: 7 OCT 2013 | DOI: 10.1002/qua.24556

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      Electron interactions with ethylene are significant because of the role of molecules in applications like semiconductor etching, plasma deposition, gaseous discharges, planetary atmosphere, and interstellar media. In this work, total and differential cross sections for ethylene over a wide energy range of 1–2000 eV are calculated. Theoretical results are compared against earlier experimental and theoretical work. A shape resonance is detected at 2 eV and ascribed to the symmetry of an electronic state.

    6. Ab initio chemical kinetics for the unimolecular decomposition of Si2H5 radical and related reverse bimolecular reactions (pages 278–288)

      Shang-Ying Wu, Yun-Min Lee, Jong-Shinn Wu and Ming-Chang Lin

      Article first published online: 7 OCT 2013 | DOI: 10.1002/qua.24557

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      Fundamental modeling of fluid dynamics and chemical reaction mechanisms is often required for the understanding of complex chemical processes occurring inside the chemical vapor deposition (CVD) chamber. The disilanyl radical (Si2H5) inside the CVD chamber is a potential reactive intermediate involved in several reactions of interest. Critical data on the kinetics and mechanisms for Si2H5 thermal decomposition and the related bimolecular reactions are presented.

    7. Multiple-pathways of carbon dioxide binding by a Lewis acid [B(C6F5)3] and a lewis base [P(tBu)3]: The energy landscape perspective (pages 289–294)

      Maoping Pu and Timofei Privalov

      Article first published online: 7 OCT 2013 | DOI: 10.1002/qua.24558

      Thumbnail image of graphical abstract

      Using the reaction-relevant two-dimensional potential energy surface, an accurate reaction-pathway mapping, and ab inito molecular dynamics, it is convincingly shown that CO2 capture by P(tBu)3 and B(C6F5)3 species has many reaction-routes to take. An explanation is given, and an ensemble of asynchronous reaction-routes of CO2 is detailed.

    8. Substituent effects on cooperativity between lithium bonds (pages 295–301)

      Mehdi D. Esrafili, Parvin Esmailpour, Fariba Mohammadian-Sabet and Mohammad Solimannejad

      Article first published online: 9 OCT 2013 | DOI: 10.1002/qua.24560

      Thumbnail image of graphical abstract

      Substituent effects on the cooperativity in a series of lithium-bonded trimmers are reported. Li-bonding enhances pair interactions on the trimer formation, and Li…N interactions are found to be stronger than corresponding Li…C linkages. Generally, the electron density at the Li···N and Li···C critical points can be regarded as a good descriptor of the degree of cooperative effects.

  3. Letters to the Editor

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor

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