Lin Xu

Zhejiang University, Hang-hsien, Zhejiang Sheng, China

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Publications (7)11.41 Total impact

  • Peng Sang · Peng Zhou · Lin Xu · Jian-Wei Zou

    No preview · Article · Jun 2013 · Chemosphere
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    ABSTRACT: In the crystal structure of the title compound, [ZnCl(2)(C(5)H(4)ClN)(2)], discrete complex mol-ecules are found in which the Zn(II) cations are coordinated by two chloride anions and the N atoms of the two 3-chloro-pyridine ligands within a slightly distorted tetra-hedron. Moreover, inter-molecular C-Cl⋯Cl-C halogen inter-actions (Cl⋯Cl = 3.442 Å) are found between the building blocks.
    Preview · Article · Jul 2011 · Acta Crystallographica Section E Structure Reports Online
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    ABSTRACT: Halogen bonding can direct the local stereochemical properties of nucleic acids by unique geometric preferences but has been inaccessible to most theoretical studies. Using a two-layer ONIOM method, halogen bonds buried in nucleic acid environments were studied by modeling the nucleotide C–Br⋯O–P contacts in 1P54 and 1RLG (PDB code). Several unconventional methods, associated with the electron density distributions of the interacting atoms, showed the formation of halogen bonds through visualization of such non-covalent interactions in real space. The contributions of halogen bonds to the local conformation of the backbones were also demonstrated through comparison with parallel binding of non-brominated nucleotides.Graphical abstractUsing a two-layer ONIOM method, halogen bonds buried in nucleic acid environments were exploited through modeling the nucleotide C–Br⋯O–P contact. Unconventional reduced density gradient (RDG) and electron localization function (ELF) analyses have been performed on halogen bonds within halogenated nucleic acid systems.View high quality image (131K)Highlights► Halogen bonds buried in nucleic acids were explored by the ONIOM method. ► Analysis of reduced density gradient was carried out on halogen bonds. ► Halogen bonds were visualized by the ELF approach. ► Flexibility of nucleic acid chains is sensitive to the presence of halogen bonds.
    No preview · Article · Jun 2011 · Chemical Physics Letters
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    ABSTRACT: The M–C–X⋯X′ halogen bond may be considered as a novel supramolecular synthon for prediction and design of polymeric metal frameworks. In this work, a set of theoretical models, consisting of two series of complexes PyCl⋯X (PyCl = NC5H4Cl-4; X = F−, Cl−, or Br−) and MPyCl⋯X (M = Cu+, Zn2+), was utilized to reveal features of M–C–X⋯X′. To explore the influence of metal centers, a detailed comparison of the properties in PyCl⋯X and MPyCl⋯X complexes was carried out. The results showed that, while coordinating to metals, interaction energies and charge transfers exhibit a remarkable increase, which have been rationalized by analyses of electrostatic potential and density difference function. Furthermore, the individual energy contributions were examined through the symmetry-adapted perturbation theory, and the results indicated that the dominant energy contribution emerges from the electrostatic and induction energy, and the electrostatic term presents a higher increment than other energy components.Graphical abstractCompared with the conventional halogen bond, C–X⋯Y, the metal coordination of organic halide can enforce the anisotropic distribution of electron density of end-x, and leads to the more directional M–C–X⋯X′ interaction.Research highlights► The metal coordination promotes an interaction of chloropyridine to halide anions. ► The increase of halogen bonding focuses mainly on the electrostatic component. ► The metal coordination to heterocycles can lead to a novel M–C–X⋯X′ synthon.
    No preview · Article · Jan 2011 · Chemical Physics
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    ABSTRACT: A set of theoretical model systems, investigated by the DFT method with hybrid basis sets, was utilized to mimic and exploit the halogen bond found in the neutral metal–organic coordination, CuCl2(NC5H4Br-3)2. The optimized calculations indicate that, while coordinating to metal ions, the end-bromine of organic halide subunit exhibits better directionality and affinity to electron density donors. Halogen bonding energies are substantial and range from −2.5 to −37.5 kcal/mol. These results reveal the importance of metal-influenced halogen bonding in directing supramolecular arrangements. To further study the nature of the halogen bond, the analyses of NBO and AIM were carried out. The conclusions show a considerable extent of charge transfer, complicated orbital interactions, and distinct bond critical points between interacting atoms upon halogen bonding.
    No preview · Article · Aug 2010 · Journal of Molecular Structure THEOCHEM
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    ABSTRACT: Ab initio calculations on the complexes formed between unsaturated hydrocarbon(R) and dihalogen molecules(XY), R⋯(XY)n (n = 1–2), have been performed at MP2/aug-cc-PVDZ level of theory. Geometrical structures, interaction energies and topological parameters derived from the theory of atoms in molecules (AIM) developed by Bader have been studied systematically to characterize the halogen⋯π interactions. The present theoretical investigation indicates that such interactions in all trimolecular complexes R⋯(XY)2 are significantly stronger than those in the corresponding bimolecular series R⋯(XY), demonstrating the existence of cooperativity effect. This may provide a theoretical basis for our understanding the reaction mechanism of the electrophilic addition of halogen to the unsaturated hydrocarbons.
    No preview · Article · Mar 2009 · Journal of Molecular Structure THEOCHEM
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    ABSTRACT: In this work, computations of density functional theory (DFT) have been carried out to investigate the interactions between the PCl unit of hexachlorocyclotriphosphazene and several common electron donors. Such small systems are selected to explore the potential P-bound halogen bonding interactions within polymeric structure and supramolecules. In all cases, the intermolecular distances are shown to be equal to or below sums of van der Waals radii of the atoms involved. Halogen bonding energies, calculated at B971/6-311+G(d,p), span over a relatively lager range, from −0.95 to −95.30 kcal/mol, which intimate that the interactions are comparable to, or even partly prevail over, the conventional hydrogen bonding. For the charge-assisted systems, calculations show that these systems can result in much stronger halogen bonding than the corresponding neutral ones. The results agree well with those of natural population analysis (NPA). Finally, the theory of atoms in molecules (AIM) was applied to provide more insight into the nature of these interactions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
    No preview · Article · Jan 2009 · International Journal of Quantum Chemistry