scholarly journals Halogen…π Interactions in the Complexes of Fluorenonophane With Haloforms

Author(s):  
Svitlana V. Shishkina ◽  
Viktoriya V. Dyakonenko ◽  
Oleg V. Shishkin ◽  
Volodimir P. Semynozhenko ◽  
Tatiana Yu. Bogashchenko ◽  
...  

Abstract The study of two complexes of fluorenonophane with CHCl3 and CHBr3 molecules has revealed that they differ mainly by the halogen bonds between host and guest molecules. The experimental and theoretical quantum chemical study has shown that the strength of a halogen bond depends on the nature of a halogen atom as well as its orientation to the π-system. The more positive electrostatic potential was revealed at the bromine atom indicating the stronger halogen bond with its participation that was confirmed by the interaction energies calculated for corresponding dimers and the evaluation of the true energy of a halogen bond. The orientation of the chlorine atom at the carbon aromatic atom instead of the center of the benzene ring leads to the shortest Hal…C distance that points out the stronger interaction according to the geometrical characteristics. The EDA analysis of the fluorenonophane complexes with CHCl3 and CHBr3 and their analogs with one halogen atom replaced by the hydrogen atom allows us to presume that the nature of halogen bonding is rather dispersive than electrostatic.

Author(s):  
Ruben D. Parra ◽  
Álvaro Castillo

The geometries and energetics of molecular self-assembly structures that contain a sequential network of cyclic halogen-bonding interactions are investigated theoretically. The strength of the halogen-bonding interactions is assessed by examining binding energies, electron charge transfer (NBO analysis) and electron density at halogen-bond critical points (AIM theory). Specifically, structural motifs having intramolecular N—X...N (X= Cl, Br, or I) interactions and the ability to drive molecular self-assemblyviathe same type of interactions are used to construct larger self-assemblies of up to three unit motifs. N—X...N halogen-bond cooperativity as a function of the self-assembly size, and the nature of the halogen atom is also examined. The cyclic network of the halogen-bonding interactions provides a suitable cavity rich in electron density (from the halogen atom lone pairs not involved in the halogen bonds) that can potentially bind an electron-deficient species such as a metal ion. This possibility is explored by examining the ability of the N—X...N network to bind Na+. Likewise, molecular self-assembly structures driven by the weaker C—X...N halogen-bonding interactions are investigated and the results compared with those of their N—X...N counterparts.


2020 ◽  
Vol 21 (18) ◽  
pp. 6571
Author(s):  
Nicholas J. Thornton ◽  
Tanja van Mourik

Halogen bonding is studied in different structures consisting of halogenated guanine DNA bases, including the Hoogsteen guanine–guanine base pair, two different types of guanine ribbons (R-I and R-II) consisting of two or three monomers, and guanine quartets. In the halogenated base pairs (except the Cl-base pair, which has a very non-planar structure with no halogen bonds) and R-I ribbons (except the At trimer), the potential N-X•••O interaction is sacrificed to optimise the N-X•••N halogen bond. In the At trimer, the astatines originally bonded to N1 in the halogen bond donating guanines have moved to the adjacent O6 atom, enabling O-At•••N, N-At•••O, and N-At•••At halogen bonds. The brominated and chlorinated R-II trimers contain two N-X•••N and two N-X•••O halogen bonds, whereas in the iodinated and astatinated trimers, one of the N-X•••N halogen bonds is lost. The corresponding R-II dimers keep the same halogen bond patterns. The G-quartets display a rich diversity of symmetries and halogen bond patterns, including N-X•••N, N-X•••O, N-X•••X, O-X•••X, and O-X•••O halogen bonds (the latter two facilitated by the transfer of halogens from N1 to O6). In general, halogenation decreases the stability of the structures. However, the stability increases with the increasing atomic number of the halogen, and the At-doped R-I trimer and the three most stable At-doped quartets are more stable than their hydrogenated counterparts. Significant deviations from linearity are found for some of the halogen bonds (with halogen bond angles around 150°).


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Briauna Hawthorne ◽  
Haiyan Fan-Hagenstein ◽  
Elizabeth Wood ◽  
Jessica Smith ◽  
Timothy Hanks

Halogen bonding between pyridine and heptafluoro-2-iodopropane (iso-C3F7I)/heptafluoro-1-iodopropane (1-C3F7I) was studied using a combination of FTIR and 19F NMR. The ring breathing vibration of pyridine underwent a blue shift upon the formation of halogen bonds with both iso-C3F7I and 1-C3F7I. The magnitudes of the shifts and the equilibrium constants for the halogen-bonded complex formation were found to depend not only on the structure of the halocarbon, but also on the solvent. The halogen bond also affected the Cα-F (C-F bond on the center carbon) bending and stretching vibrations in iso-C3F7I. These spectroscopic effects show some solvent dependence, but more importantly, they suggest the possibility of intermolecular halogen bonding among iso-C3F7I molecules. The systems were also examined by 19F NMR in various solvents (cyclohexane, hexane, chloroform, acetone, and acetonitrile). NMR dilution experiments support the existence of the intermolecular self-halogen bonding in both iso-C3F7I and 1-C3F7I. The binding constants for the pyridine/perfluoroalkyl iodide halogen bonding complexes formed in various solvents were obtained through NMR titration experiments. Quantum chemical calculations were used to support the FTIR and 19F NMR observations.


2015 ◽  
Vol 71 (10) ◽  
pp. 900-902 ◽  
Author(s):  
Alan K. Brisdon ◽  
Abeer M. T. Muneer ◽  
Robin G. Pritchard

Halogen bonding is an intermolecular interaction capable of being used to direct extended structures. Typical halogen-bonding systems involve a noncovalent interaction between a Lewis base, such as an amine, as an acceptor and a halogen atom of a halofluorocarbon as a donor. Vapour-phase diffusion of 1,4-diazabicyclo[2.2.2]octane (DABCO) with 1,2-dibromotetrafluoroethane results in crystals of the 1:1 adduct, C2Br2F4·C6H12N2, which crystallizes as an infinite one-dimensional polymeric structure linked by intermolecular N...Br halogen bonds [2.829 (3) Å], which are 0.57 Å shorter than the sum of the van der Waals radii.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1589 ◽  
Author(s):  
Yunwen Tao ◽  
Yue Qiu ◽  
Wenli Zou ◽  
Sadisha Nanayakkara ◽  
Seth Yannacone ◽  
...  

Periodic local vibrational modes were calculated with the rev-vdW-DF2 density functional to quantify the intrinsic strength of the X-I⋯OA-type halogen bonding (X = I or Cl; OA: carbonyl, ether and N-oxide groups) in 32 model systems originating from 20 molecular crystals. We found that the halogen bonding between the donor dihalogen X-I and the wide collection of acceptor molecules OA features considerable variations of the local stretching force constants (0.1–0.8 mdyn/Å) for I⋯O halogen bonds, demonstrating its powerful tunability in bond strength. Strong correlations between bond length and local stretching force constant were observed in crystals for both the donor X-I bonds and I⋯O halogen bonds, extending for the first time the generalized Badger’s rule to crystals. It is demonstrated that the halogen atom X controlling the electrostatic attraction between the σ -hole on atom I and the acceptor atom O dominates the intrinsic strength of I⋯O halogen bonds. Different oxygen-containing acceptor molecules OA and even subtle changes induced by substituents can tweak the n → σ ∗ (X-I) charge transfer character, which is the second important factor determining the I⋯O bond strength. In addition, the presence of the second halogen bond with atom X of the donor X-I bond in crystals can substantially weaken the target I⋯O halogen bond. In summary, this study performing the in situ measurement of halogen bonding strength in crystalline structures demonstrates the vast potential of the periodic local vibrational mode theory for characterizing and understanding non-covalent interactions in materials.


Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1075
Author(s):  
Cody Loy ◽  
Matthias Zeller ◽  
Sergiy V. Rosokha

The wide-range variation of the strength of halogen bonds (XB) not only facilitates a variety of applications of this interaction, but it also allows examining the relation (and interconversion) between supramolecular and covalent bonding. Herein, the Br…Cl halogen bonding in a series of complexes of bromosubstituted electrophiles (R-Br) with chloride anions were examined via X-ray crystallographic and computational methods. Six co-crystals showing such bonding were prepared by evaporation of solutions of R-Br and tetra-n-propylammonium chloride or using Cl− anions released in the nucleophilic reaction of 1,4-diazabicyclo[2.2.2]octane with dichloromethane in the presence of R-Br. The co-crystal comprised networks formed by 3:3 or 2:2 halogen bonding between R-Br and Cl−, with the XB lengths varying from 3.0 Å to 3.25 Å. Analysis of the crystallographic database revealed examples of associations with substantially longer and shorter Br…Cl separations. DFT computations of an extended series of R–Br…Cl− complexes confirmed that the judicious choice of brominated electrophile allows varying halogen Br…Cl bond strength and length gradually from the values common for the weak intermolecular complexes to that approaching a fully developed covalent bond. This continuity of halogen bond strength in the experimental (solid-state) and calculated associations indicates a fundamental link between the covalent and supramolecular bonding.


2018 ◽  
Author(s):  
Robert A. Shaw ◽  
Grant Hill

In this article we develop a simple statistical model for the prediction of halogen bond interaction energies at equilibrium geometries. The model is based on explicitly correlated coupled cluster results and produces root-mean-squared deviations of 0.14 and 0.28 kcal mol<sup>–1</sup> over separate fitting and validation sets, respectively. We also show how the model can be used to highlight cases where induction or dispersion significantly affect the underlying nature of the interaction.<br>


2004 ◽  
Vol 108 (33) ◽  
pp. 12327-12332 ◽  
Author(s):  
Sławomir Berski ◽  
Zbigniew Ciunik ◽  
Krzysztof Drabent ◽  
Zdzisław Latajka ◽  
Jarosław Panek

2015 ◽  
Vol 87 (1) ◽  
pp. 15-41 ◽  
Author(s):  
Andreas Vargas Jentzsch

AbstractHalogen bonding is the noncovalent interaction where the halogen atom acts as an electrophile towards Lewis bases. Known for more than 200 years, only recently it has attracted interest in the context of solution-phase applications, especially during the last decade which was marked by the introduction of multitopic systems. In addition, the small yet rich collection of halogen-bond donor moieties that appeared in this period is shown to be versatile enough as to be applied in virtually any solvent system. This review covers the applications of halogen bonding in solution during the past ten years in a semi-comprehensive way. Emphasis is made on molecular recognition, catalytic applications and anion binding and transport. Medicinal applications are addressed as well with key examples. Focussing on the major differences observed for halogen bonding, as compared to the ubiquitous hydrogen bonding, it aims to contribute to the design of future solution-phase applications.


2017 ◽  
Vol 203 ◽  
pp. 333-346 ◽  
Author(s):  
Sebastiaan B. Hakkert ◽  
Jürgen Gräfenstein ◽  
Mate Erdelyi

We have studied the applicability of15N NMR spectroscopy in the characterization of the very weak halogen bonds of nonfluorinated halogen bond donors with a nitrogenous Lewis base in solution. The ability of the technique to detect the relative strength of iodine-, bromine- and chlorine-centered halogen bonds, as well as solvent and substituent effects was evaluated. Whereas computations on the DFT level indicate that15N NMR chemical shifts reflect the diamagnetic deshielding associated with the formation of a weak halogen bond, the experimentally observed chemical shift differences were on the edge of detectability due to the low molar fraction of halogen-bonded complexes in solution. The formation of the analogous yet stronger hydrogen bond of phenols have induced approximately ten times larger chemical shift changes, and could be detected and correlated to the electronic properties of substituents of the hydrogen bond donors. Overall,15N NMR is shown to be a suitable tool for the characterization of comparably strong secondary interactions in solution, but not sufficiently accurate for the detection of the formation of thermodynamically labile, weak halogen bonded complexes.


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