International Journal of Quantum Chemistry

Cover image for Vol. 113 Issue 20

15 October 13

Volume 113, Issue 20

Pages i–iv, 2251–2332

  1. Cover Image

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      Cover Image, Volume 113, Issue 20 (pages i–ii)

      Article first published online: 6 SEP 2013 | DOI: 10.1002/qua.24538

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      Two macrocyclic molecules, tetrakis-(p-methoxyphenyl)porphyrin and its Zn-containing complex, are model structures for the study of the charge-transfer processes in noncovalent p-stacking systems, which is one of the most important properties in discotic liquid crystals (DLC). In this sense, density functional computations, including dispersion corrections, are used to study the electronic interactions on these aromatic cores by Ximena Zarate, Eduardo Schott, Leonor Alvarado-Soto, and Todd C. Sutherland on page 2287. The cover image shows a zoom of the packing of these molecules in DLC phases, which are modeled by their face-to-face dimeric conformations whose lowest unoccupied molecular orbitals (LUMO) overlap through the dimer, indicating the electron transfer character.

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      Inside Cover, Volume 113, Issue 20 (pages iii–iv)

      Article first published online: 6 SEP 2013 | DOI: 10.1002/qua.24539

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      Electron transport through DNA-based molecular junctions opens a door for fast and cheap DNA sequencing. The sequence of DNA can be identified according to its distinct current–voltage characteristics. This can be achieved by using titanium nitride as an electrode in the molecular junction, as presented by Xiang Chen on page 2295. Rapid DNA sequencing is able to provide abundant information on the human genome and may lead to a revolution in medical care.

  2. Full Papers

    1. Top of page
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    3. Full Papers
    1. Geometry, stability, and isomerization of BnN2 (n = 1−6) isomers (pages 2251–2260)

      Wenwen Cui, Cheng Wang, Jingling Shao and Xiaolei Zhu

      Article first published online: 30 MAY 2013 | DOI: 10.1002/qua.24443

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      The study of clusters plays a crucial role in the comprehension of the scale-up from molecule to bulk material. The prediction of kinetic stability for boron–nitrogen (BnN2) clusters is very challenging since the potential energy surface becomes very complicated as the number of atoms per cluster increases. This work finds some thermodynamically and kinetically stable BnN2 isomers that should be experimentally detectable.

    2. Ab initio study of the π–π interactions between CO2 and benzene, pyridine, and pyrrole (pages 2261–2266)

      Long Chen, Fenglei Cao and Huai Sun

      Article first published online: 24 MAY 2013 | DOI: 10.1002/qua.24444

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      The climatic effects of rising atmospheric levels of carbon have motivated extensive research into carbon sequestration using porous metal organic frameworks (MOFs). Weak intermolecular interactions between carbon dioxide (CO2) and MOFs largely determine their carbon uptake. This work studies these interactions between CO2 and aromatic species representing common building blocks of MOFs and finds an interesting correlation to molecular aromaticity. The results suggest design of efficient MOFs through use of linkers with enhanced aromaticity.

    3. Theoretical study of enantiomeric and geometric control in chiral guanidine-catalyzed asymmetric 1,4-addition of 5H-oxazol-4-ones (pages 2267–2276)

      Nan Lu and Huatian Wang

      Article first published online: 9 APR 2013 | DOI: 10.1002/qua.24447

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      Chiral guanidine catalysts are widely used in various asymmetric reactions to obtain high enantioselectivity. However, the reaction of asymmetric 1,4-addition catalyzed by bicyclic chiral guanidine is not well understood. This article presents the origin of high enantiomeric and geometric control for this type of guanidine. The results are expected to contribute to the design and modification of guanidine catalysts.

    4. Generalized relativistic effective core potential calculations of the adiabatic potential curve and spectroscopic constants for the ground electronic state of the Ca2 molecule (pages 2277–2281)

      Nikolai S. Mosyagin, Aleksander N. Petrov, Anatoly V. Titov and Andrei V. Zaitsevskii

      Article first published online: 9 APR 2013 | DOI: 10.1002/qua.24448

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      The Ca2 molecule is a difficult system for ab initio modeling due to the multiconfigurational nature of the ground state, weak interatomic interaction, and noticeable relativistic corrections. To estimate the computational accuracy of the quantum chemical methods used, the calculated results are compared with the corresponding experimental data. The potential energy curve, dissociation energy, equilibrium internuclear distance, and spectroscopic constants for this molecule are obtained.

    5. Proper quantization rule approach to three-dimensional quantum dots (pages 2282–2286)

      Fernando Adan Serrano and Shi-Hai Dong

      Article first published online: 2 APR 2013 | DOI: 10.1002/qua.24449

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      A formalism is developed to calculate the energy levels of an electron subject to a central force potential confined in a spherical quantum dot with radius rC using the proper quantization rule. Obtained numerical results are in good agreement with exact solutions. The case of a three-dimensionally confined linear harmonic oscillator subjected to a Coulomb force-field is used as an illustrative example. The rule illustrates its simplicity in calculations and beauty of symmetrical expression.

    6. A molecular study of tetrakis(p-methoxyphenyl)porphyrin and its Zn(II) complex as discotic liquid crystals (pages 2287–2294)

      Ximena Zarate, Eduardo Schott, Leonor Alvarado-Soto and Todd C. Sutherland

      Article first published online: 9 APR 2013 | DOI: 10.1002/qua.24450

      Thumbnail image of graphical abstract

      Two macrocyclic molecules, tetrakis-(p-methoxyphenyl)porphyrin and its Zn-containing complex, represent model structures for the study of the charge-transfer processes in noncovalent π-stacking systems. Density functional theory calculations, incorporating dispersion corrections, suggest that the effect of the metallic center over the electron transfer property is nearly negligible in these systems.

    7. DNA sequencing with titanium nitride electrodes (pages 2295–2305)

      Xiang Chen

      Article first published online: 9 APR 2013 | DOI: 10.1002/qua.24451

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      The extraction of human genomic information is expected to lead to a revolution in development of individualized medical therapies. Electron transport through DNA-based molecular junctions opens the door to fast and cheap DNA sequencing, on the basis of distinct current–voltage characteristics. This work studies two kinds of sequencing devices with titanium nitride and gold electrodes theoretically. The molecular conductances obtained suggest that these are viable candidate devices for fast DNA sequencing.

    8. Autocatalytic decomposition of carbonic acid (pages 2306–2311)

      Sven A. de Marothy

      Article first published online: 4 JUN 2013 | DOI: 10.1002/qua.24452

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      Although the gas-phase instability of carbonic acid has long been known, previous theoretical investigations have indicated the possibility of gaseous carbonic acid being remarkably persistent in the absence of water. Here, a novel autocatalytic decomposition pathway is investigated using the coupled-cluster method. The results indicate that the rate-limiting step here is similar in energy to that of water-catalyzed decomposition reactions and significantly lower than for the uncatalyzed decomposition.

    9. Inheritance and correlation of nucleic acid pyrimidine bases (pages 2312–2318)

      Zejin Yang, Patrick Duffy and Feng Wang

      Article first published online: 21 MAY 2013 | DOI: 10.1002/qua.24453

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      Orbital momentum distributions reveal that pyrimidine exhibits less similarity to the nucleic acid (NA) bases (cytosine, thymine, and uracil) than the NA bases do to each other. The high symmetry of pyrimidine restricts interchanges between the x- and y-components of its orbitals, whereas the NA bases are more flexible as they do not possess such symmetry restriction. This may be one reason that pyrimidine does not appear in most of the RNA and DNA polymers.

    10. Gas storage of simple molecules in boron oxide nanocapsules (pages 2319–2332)

      Mehdi Zamani, Hossein A. Dabbagh and Hossein Farrokhpour

      Article first published online: 21 MAY 2013 | DOI: 10.1002/qua.24456

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      Encapsulation of atoms and molecules by fullerenes is a subject of current research interest, usually achieved experimentally with difficulty, under high pressure. This work examines the capability of boron oxide nanocapsules to store some simple gaseous molecules both endo- and exohedrally. The study finds that boron oxide complexes of different geometries have gas storage capabilities similar to C60. The results are expected to excite further experimental work in this field.

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