Journal of Computational Chemistry

Cover image for Vol. 36 Issue 11

April 30, 2015

Volume 36, Issue 11

Pages i–vi, 785–869

  1. Cover Image

    1. Top of page
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      Cover Image, Volume 36, Issue 11 (pages i–ii)

      Article first published online: 26 MAR 2015 | DOI: 10.1002/jcc.23907

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      On page 861 (DOI: 10.1002/jcc.23871), Alex Domingo, Celestino Angeli, Coen de Graaf, and Vincent Robert report the intervalence charge transfer (IVCT) between the metal centers of a bi-iron complex induces a response of the whole electronic structure of the compound. The response effects consist of an electronic reorganization that affects each molecular orbital of the complex differently. The π- and n-type orbitals localized on coordinating atoms undergo the largest polarization, being even larger than that of the Fe 3d-like orbitals involved in the transfer. The electronic reorganization follows the induced dipole moment by the IVCT, but having a weaker effect on the orbitals close to the Fe center accepting the transferring electron.

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      Cover Image, Volume 36, Issue 11 (pages iii–iv)

      Article first published online: 26 MAR 2015 | DOI: 10.1002/jcc.23908

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      Can allenes and their derivatives perform as efficient leaving groups in catalysis processes? This is the question addressed on page 795 (DOI: 10.1002/jcc.23855) by Nishamol Kuriakose and Kumar Vanka. Specifically, the possibility of these interesting compounds acting as leaving groups in the case of olefin metathesis with the Grubbs catalyst is explored. The investigation is performed with high level quantum chemical calculations using density functional theory (DFT). The results for a range of different allene and substituted allene cases indicate that these compounds would be better by several orders of magnitude in comparison to currently employed leaving groups. This interesting result showcases the potential of this important new class of compounds.

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      Cover Image, Volume 36, Issue 11 (pages v–vi)

      Article first published online: 26 MAR 2015 | DOI: 10.1002/jcc.23909

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      According to high accuracy quantum chemical computations up to the CCSDTQ level, both 1A1 and 3A2 states of silicon trimer are degenerate. An intersystem crossing between both states appears at a point of α = 68 ± 2° lying only 16 ± 4 kJ/mol above the ground state. On page 805 (DOI: 10.1002/jcc.23856), Nguyen Minh Tam, Tran Dieu Hang, Hung Tan Pham, Huyen Thi Nguyen, My Phuong Pham-Ho, Pablo A. Denis, and Minh Tho Nguyen probe the chemical bonding of Si3 using Walsh diagrams, electron localization function, and ring current analyses. The singlet three-membered Si3 exhibits paratropic ring current, which arises exclusively from σ electrons. Attachment of H+ and Li+ cations renders the ring more anti-aromatic.

  2. Full Papers

    1. Top of page
    2. Cover Image
    3. Full Papers
    1. Dividing a complex reaction involving a hypervalent iodine reagent into three limiting mechanisms by ab initio molecular dynamics (pages 785–794)

      Oliver Sala, Hans Peter Lüthi, Antonio Togni, Marcella Iannuzzi and Jürg Hutter

      Article first published online: 12 MAR 2015 | DOI: 10.1002/jcc.23857

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      Hypervalent iodine reagents such as λ3-iodanes are frequently used for electrophilic atom/group-transfers. However, little is known about the mechanistic details of these reactions. Based on ab initio molecular dynamic simulations of the trifluoromethylation of two different nucleophiles with a λ3-iodane in acetonitrile solution, it is shown that the reaction may occur via three concomitant mechanisms (reductive elimination, nucleophilic substitution, radical mechanism), thus each one defining the limits in which the reaction may occur.

    2. Can substituted allenes be highly efficient leaving groups in catalytic processes? A computational investigation (pages 795–804)

      Nishamol Kuriakose and Kumar Vanka

      Article first published online: 12 MAR 2015 | DOI: 10.1002/jcc.23855

      Thumbnail image of graphical abstract

      Can allenes and their derivatives perform as efficient leaving groups in catalysis processes? This is the question that is addressed in this study. The results for a range of different allene and substituted allene cases indicate that these compounds would be better by several orders of magnitude in comparison to currently employed leaving groups. This interesting result showcases the potential of this important new class of compounds.

    3. Bonding and singlet–triplet gap of silicon trimer: Effects of protonation and attachment of alkali metal cations (pages 805–815)

      Nguyen Minh Tam, Tran Dieu Hang, Hung Tan Pham, Huyen Thi Nguyen, My Phuong Pham-Ho, Pablo A. Denis and Minh Tho Nguyen

      Article first published online: 19 FEB 2015 | DOI: 10.1002/jcc.23856

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      Both 1A1 and 3A2 states of Si3 are degenerate. The H+, Li+, and Na+ cations favor the singlet state, whereas K+ favors the triplet. Some thermochemical parameters are predicted: PA(Si3) = 830 ± 4, LiCA(Si3) =108 ± 8, NaCA(Si3) = 79 ± 8, and KCA(Si3) = 44 ± 8 kJ/mol. The ring current shows that the singlet three-membered Si3 ring is, at most, nonaromatic. Attachment of H+ and Li+ renders it anti-aromatic.

    4. An ab initio study of nuclear volume effects for isotope fractionations using two-component relativistic methods (pages 816–820)

      Keisuke Nemoto, Minori Abe, Junji Seino and Masahiko Hada

      Article first published online: 25 FEB 2015 | DOI: 10.1002/jcc.23858

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      Nuclear volume term is a main term in the chemical equilibrium constants of isotope fractionations with heavy-element isotopes. The nuclear volume term can be calculated by the four-component Dirac-Hartree-Fock method. In this work, various types of two-component quasi-relativistic methods are performed in an attempt to find alternatives to the time-consuming four-component method. One of the infinite-order Douglass-Kroll-Hess methods is found to be accurate, but 30 times faster than the four-component method.

    5. Theoretical investigation of the halogen bonded complexes between carbonyl bases and molecular chlorine (pages 821–832)

      Wiktor Zierkiewicz, Dariusz C. Bieńko, Danuta Michalska and Thérèse Zeegers-Huyskens

      Article first published online: 27 FEB 2015 | DOI: 10.1002/jcc.23860

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      The halogen-bonded complexes between six carbonyl bases and molecular chlorine are investigated theoretically. The study includes the optimized geometries and the interaction energies along with an extended natural bond orbital analysis. The interaction energies calculated at the CCSD(T)/aug-cc-pVTZ level range between −1.61 and −3.50 kcal mol−1. These energies are related to the ionization potential and the proton affinity of the carbonyl bases.

    6. One-electron images in real space: Natural adaptive orbitals (pages 833–843)

      Marcos Menéndez, Roberto Álvarez Boto, Evelio Francisco and Ángel Martín Pendás

      Article first published online: 18 FEB 2015 | DOI: 10.1002/jcc.23861

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      A hierarchical set of one-electron functions called natural adaptive orbitals (NAdOs) is introduced. n-Center NAdOs decompose real space n-center bonding indices into one-electron contributions. NAdOs maintain their meaning both for correlated and noncorrelated descriptions.

    7. Probing the reactivity of microhydrated α-nucleophile in the anionic gas-phase SN2 reaction (pages 844–852)

      Wen-Yang Zhao, Jie Yu, Si-Jia Ren, Xi-Guang Wei, Fang-Zhou Qiu, Peng-Hui Li, He Li, Yi-Peng Zhou, Chang-Zhen Yin, An-Pu Chen, Hao Li, Lei Zhang, Jun Zhu, Yi Ren and Kai-Chung Lau

      Article first published online: 11 MAR 2015 | DOI: 10.1002/jcc.23862

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      The α-effect (ΔΔGα; normal for n = 0, bold for n = 1, and italic for n = 2) exhibited by α-oxy-Nus becomes weaker with microsolvation of nucleophiles, whereas the reactivity of ROO(H2O)n = 1,2 are enhanced compared with RO(H2O)n = 1,2 (R = H, CH3), which may be induced by the significant reduction of basicity difference between them from n = 0 to n = 1 to n = 2.

    8. Solvatochromic shifts of Br2 and I2 in water cages of type 512, 51262, 51263, and 51264 (pages 853–860)

      Nils Middendorf, Katharina Krause and Sebastian Höfener

      Article first published online: 18 FEB 2015 | DOI: 10.1002/jcc.23863

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      Solvatochromic shifts are estimated for molecular bromine and iodine trapped in selected clathrate hydrate cages using frozen-density embedding, allowing for the combination of scalar-relativistic and nonrelativistic methods for heavy halogens and light water molecules, respectively.

    9. Electronic reorganization triggered by electron transfer: The intervalence charge transfer of a Fe3+/Fe2+ bimetallic complex (pages 861–869)

      Alex Domingo, Celestino Angeli, Coen de Graaf and Vincent Robert

      Article first published online: 5 MAR 2015 | DOI: 10.1002/jcc.23871

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      The electronic reorganization induced by the intervalence charge transfer of a synthetic nonheme binuclear mixed-valence Fe3+/Fe2+ complex determines the energy cost of the electron transfer. The largest electronic reorganization occurs in the pyrimidinic N atoms and the bridge O of the first coordination shell, being weaker in the metal centres. The adaptation of the molecular orbitals to the electron transfer is sufficient to inverse the spectroscopy and generate a metastable electron transfer state.

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