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Journal ArticleDOI

Interplay between halogen bond and lithium bond in MCN-LiCN-XCCH (M = H, Li, and Na; X = Cl, Br, and I) complex: the enhancement of halogen bond by a lithium bond.

Qingzhong Li1, Ran Li1, Zhenbo Liu1, Wenzuo Li1, Jianbo Cheng1 
30 Nov 2011-Journal of Computational Chemistry (Wiley Subscription Services, Inc., A Wiley Company)-Vol. 32, Iss: 15, pp 3296-3303
TL;DR: The results show that the electrostatic interaction plays an important role in the enhancement of halogen bond.
Abstract: Quantum chemical calculations have been performed to study the complex of MCN-LiCN-XCCH (M = H, Li, and Na; X = Cl, Br, and I). The aim is to study the cooperative effect between halogen bond and lithium bond. The alkali metal has an enhancing effect on the lithium bond, making it increased by 77 and 94% for the Li and Na, respectively. There is the cooperativity between the lithium bond and halogen bond. The former has a larger enhancing effect on the latter, being in a range of 11.7–29.4%. The effect of cooperativity on the halogen bond is dependent on the type of metal and halogen atoms. The enhancing mechanism has been analyzed in views with the orbital interaction, charge transfer, dipole moment, polarizability, atom charges, and electrostatic potentials. The results show that the electrostatic interaction plays an important role in the enhancement of halogen bond. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Citations
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TL;DR: The σ-hole and π-hole are the regions with positive surface electrostatic potential on the molecule entity; the former specifically refers to the positive region of a molecular entity along extension of the Y-Ge/P/Se/X covalent ρ-bond.
Abstract: The σ-hole and π-hole are the regions with positive surface electrostatic potential on the molecule entity; the former specifically refers to the positive region of a molecular entity along extension of the Y–Ge/P/Se/X covalent σ-bond (Y = electron-rich group; Ge/P/Se/X = Groups IV–VII), while the latter refers to the positive region in the direction perpendicular to the σ-framework of the molecular entity. The directional noncovalent interactions between the σ-hole or π-hole and the negative or electron-rich sites are named σ-hole bond or π-hole bond, respectively. The contributions from electrostatic, charge transfer, and other terms or Coulombic interaction to the σ-hole bond and π-hole bond were reviewed first followed by a brief discussion on the interplay between the σ-hole bond and the π-hole bond as well as application of the two types of noncovalent interactions in the field of anion recognition. It is expected that this review could stimulate further development of the σ-hole bond and π-hole bon...

437 citations

Journal ArticleDOI
Qingzhong Li1, Ran Li1, Xiao-Feng Liu1, Wenzuo Li1, Jianbo Cheng1 
TL;DR: The present study examines how pnicogen-bonding and halogen bonds mutually influence each other in the XCl-FH(2)P-NH(3) complex at the MP2/aug-cc-pVTZ level.
Abstract: We analyze the interplay between pnicogen-bonding and halogen-bonding interactions in the XCl-FH(2)P-NH(3) (X=F, OH, CN, NC, and FCC) complex at the MP2/aug-cc-pVTZ level. Synergetic effects are observed when pnicogen and halogen bonds coexist in the same complex. These effects are studied in terms of geometric and energetic features of the complexes. Natural bond orbital theory and Bader's theory of "atoms in molecules" are used to characterize the interactions and analyze their enhancement with varying electron density at critical points and orbital interactions. The physical nature of the interactions and the mechanism of the synergetic effects are studied using symmetry-adapted perturbation theory. By taking advantage of all the aforementioned computational methods, the present study examines how both interactions mutually influence each other.

120 citations

Journal ArticleDOI
TL;DR: 1,4-diiodo-perfluorobenzene, a very effective building block for crystal engineering based on halogen bonding, is selected in this work both as electron-deficient π aromatic ring and as halogen bond donor.
Abstract: Energetic effects between halogen bonds and anion-π or lone pair-π interactions have been investigated by means of ab initio MP2 calculations. 1,4-diiodo-perfluorobenzene, a very effective building block for crystal engineering based on halogen bonding, is selected in this work both as electron-deficient π aromatic ring and as halogen bond donor. Additive and diminutive effects are observed when halogen bonds and anion-π/lone pair-π interactions coexist in the same complex, which can be ascribed to the same direction of charge transfer for the two interactions. These effects have been analyzed in detail by the structural, energetic, and AIM properties of the complexes. Finally, experimental evidence of the combination of the interactions has been obtained from the Cambridge Structural Database.

76 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a direct difference method for the computation of molecular interactions has been based on a bivariational transcorrelated treatment, together with special methods for the balancing of other errors.
Abstract: A new direct difference method for the computation of molecular interactions has been based on a bivariational transcorrelated treatment, together with special methods for the balancing of other errors. It appears that these new features can give a strong reduction in the error of the interaction energy, and they seem to be particularly suitable for computations in the important region near the minimum energy. It has been generally accepted that this problem is dominated by unresolved difficulties and the relation of the new methods to these apparent difficulties is analysed here.

19,483 citations

Journal ArticleDOI
TL;DR: In this paper, the authors carried out a natural bond order B3LYP analysis of the molecules CF(3)X, with X = F, Cl, Br and I. The results showed that the Cl and Br atoms in these molecules closely approximate the [Formula: see text] configuration, where the z-axis is along the R-X bond.
Abstract: Halogen bonding refers to the non-covalent interactions of halogen atoms X in some molecules, RX, with negative sites on others. It can be explained by the presence of a region of positive electrostatic potential, the sigma-hole, on the outermost portion of the halogen's surface, centered on the R-X axis. We have carried out a natural bond order B3LYP analysis of the molecules CF(3)X, with X = F, Cl, Br and I. It shows that the Cl, Br and I atoms in these molecules closely approximate the [Formula: see text] configuration, where the z-axis is along the R-X bond. The three unshared pairs of electrons produce a belt of negative electrostatic potential around the central part of X, leaving the outermost region positive, the sigma-hole. This is not found in the case of fluorine, for which the combination of its high electronegativity plus significant sp-hybridization causes an influx of electronic charge that neutralizes the sigma-hole. These factors become progressively less important in proceeding to Cl, Br and I, and their effects are also counteracted by the presence of electron-withdrawing substituents in the remainder of the molecule. Thus a sigma-hole is observed for the Cl in CF(3)Cl, but not in CH(3)Cl.

1,893 citations

Journal ArticleDOI
TL;DR: In this article, a series of correlation consistent basis sets have been developed for the post-d group 16-18 elements in conjunction with small-core relativistic pseudopotentials of the energy-consistent variety.
Abstract: A series of correlation consistent basis sets have been developed for the post-d group 16–18 elements in conjunction with small-core relativistic pseudopotentials of the energy-consistent variety. The latter were adjusted to multiconfiguration Dirac–Hartree–Fock data based on the Dirac–Coulomb–Breit Hamiltonian. The outer-core (n−1)spd shells are explicitly treated together with the nsp valence shell with these PPs. The accompanying cc-pVnZ-PP and aug-cc-pVnZ-PP basis sets range in size from DZ to 5Z quality and yield systematic convergence of both Hartree–Fock and correlated total energies. In addition to the calculation of atomic electron affinities and dipole polarizabilities of the rare gas atoms, numerous molecular benchmark calculations (HBr, HI, HAt, Br2, I2, At2, SiSe, SiTe, SiPo, KrH+, XeH+, and RnH+) are also reported at the coupled cluster level of theory. For the purposes of comparison, all-electron calculations using the Douglas–Kroll–Hess Hamiltonian have also been carried out for the haloge...

1,778 citations

Journal ArticleDOI
TL;DR: The present survey of protein and nucleic acid structures reveals similar halogen bonds as potentially stabilizing inter- and intramolecular interactions that can affect ligand binding and molecular folding that offer new and versatile tools for the design of ligands as drugs and materials in nanotechnology.
Abstract: Short oxygen-halogen interactions have been known in organic chemistry since the 1950s and recently have been exploited in the design of supramolecular assemblies. The present survey of protein and nucleic acid structures reveals similar halogen bonds as potentially stabilizing inter- and intramolecular interactions that can affect ligand binding and molecular folding. A halogen bond in biomolecules can be defined as a short C-X...O-Y interaction (C-X is a carbon-bonded chlorine, bromine, or iodine, and O-Y is a carbonyl, hydroxyl, charged carboxylate, or phosphate group), where the X...O distance is less than or equal to the sums of the respective van der Waals radii (3.27 A for Cl...O, 3.37 A for Br...O, and 3.50 A for I...O) and can conform to the geometry seen in small molecules, with the C-X...O angle approximately 165 degrees (consistent with a strong directional polarization of the halogen) and the X...O-Y angle approximately 120 degrees . Alternative geometries can be imposed by the more complex environment found in biomolecules, depending on which of the two types of donor systems are involved in the interaction: (i) the lone pair electrons of oxygen (and, to a lesser extent, nitrogen and sulfur) atoms or (ii) the delocalized pi -electrons of peptide bonds or carboxylate or amide groups. Thus, the specific geometry and diversity of the interacting partners of halogen bonds offer new and versatile tools for the design of ligands as drugs and materials in nanotechnology.

1,421 citations