Complementary Features of Inorganic (M–X) and Organic (C–X′) Halogens in C–X′···X–M Halogen Bonds: A Study Based on Structure, Energy, and Topological Electron Density

Analysis of the valence angles of the Si and carbon atoms of the C-S bond in the obtained complexes of CiVg2 c (5Z, 5'Z)-2,2’-(ethane-1,2-diyldisulfanyldiyl)bis(5-(2-pyridylmethylene)-3-allyl-3,5-dihydro-4Нimidazole-4-one) unambiguously indicates the determinant effect of the non-valent interactions of the electron density centroids of the NEP of bromine atoms and sulfur atoms, leading to a change in the plane structure of Cu(II) towards tetrahedral with a likely change in the magnetochemical properties of the copper atom, and the angle of rotation of the planes is almost 900. This interaction is the opposite of what is commonly called a halogen bond. In this case, it is an "anti-halogen" bond.

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Relationships between Interaction Energy and Electron Density Properties for Homo Halogen Bonds of the [(A)nY–X···X–Z(B)m] Type (X = Cl, Br, I)

Molecules ◽

10.3390/molecules24152733 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2733 ◽

Cited By ~ 6

Author(s):

Maxim L. Kuznetsov

Keyword(s):

Kinetic Energy ◽

Interaction Energy ◽

Electron Density ◽

Bond Critical Point ◽

Kinetic Energy Density ◽

Large Set ◽

Halogen Bonds ◽

Absolute Deviation ◽

The Individual ◽

Best Estimator

Relationships between interaction energy (Eint) and electron density properties at the X···X bond critical point or the d(X···X) distance were established for the large set of structures [(A)nY–X···X–Z(B)m] bearing the halogen bonds Cl···Cl, Br···Br, and I···I (640 structures in total). The best estimator of Eint is the kinetic energy density (Gb), which reasonably approximates the whole set of the structures as −Eint = 0.128Gb2 − 0.82Gb + 1.66 (R2 = 0.91, mean absolute deviation 0.39 kcal/mol) and demonstrates low dispersion. The potential and kinetic energy densities, electron density, and the d(X···X) distance behave similarly as estimators of Eint for the individual series Cl···Cl, Br···Br, and I···I. A number of the Eint(property) correlations are recommended for the practical application in the express estimates of the strength of the homo-halogen bonds.

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Noncovalent Bonds, Spectral and Thermal Properties of Substituted Thiazolo[2,3-b][1,3]thiazinium Triiodides

Crystals ◽

10.3390/cryst9100506 ◽

2019 ◽

Vol 9 (10) ◽

pp. 506 ◽

Cited By ~ 6

Author(s):

Irina Yushina ◽

Natalya Tarasova ◽

Dmitry Kim ◽

Vladimir Sharutin ◽

Ekaterina Bartashevich

Keyword(s):

Electron Density ◽

Noncovalent Interactions ◽

Material Design ◽

Spectroscopic Properties ◽

Structural Features ◽

Halogen Bonds ◽

X Ray Diffraction ◽

Raman Spectroscopic ◽

Pairwise Interactions ◽

Noncovalent Bonds

The interrelation between noncovalent bonds and physicochemical properties is in the spotlight due to the practical aspects in the field of crystalline material design. Such study requires a number of similar substances in order to reveal the effect of structural features on observed properties. For this reason, we analyzed a series of three substituted thiazolo[2,3-b][1,3]thiazinium triiodides synthesized by an iodocyclization reaction. They have been characterized with the use of X-ray diffraction, Raman spectroscopy, and thermal analysis. Various types of noncovalent interactions have been considered, and an S…I chalcogen bond type has been confirmed using the electronic criterion based on the calculated electron density and electrostatic potential. The involvement of triiodide anions in the I…I halogen and S…I chalcogen bonding is reflected in the Raman spectroscopic properties of the I–I bonds: identical bond lengths demonstrate different wave numbers of symmetric triiodide vibration and different values of electron density at bond critical points. Chalcogen and halogen bonds formed by the terminal iodine atom of triiodide anion and numerous cation…cation pairwise interactions can serve as one of the reasons for increased thermal stability and retention of iodine in the melt under heating.

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Charge-Assisted Halogen Bonds in Halogen-Substituted Pyridinium Salts: Experimental Electron Density

Crystal Growth & Design ◽

10.1021/acs.cgd.6b01562 ◽

2017 ◽

Vol 17 (5) ◽

pp. 2357-2364 ◽

Cited By ~ 11

Author(s):

Ai Wang ◽

Ruimin Wang ◽

Irmgard Kalf ◽

Angelika Dreier ◽

Christian W. Lehmann ◽

...

Keyword(s):

Electron Density ◽

Pyridinium Salts ◽

Halogen Bonds ◽

Experimental Electron Density

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Testing the limits of halogen bonding in coordination chemistry

CrystEngComm ◽

10.1039/c7ce01989k ◽

2018 ◽

Vol 20 (5) ◽

pp. 539-549 ◽

Cited By ~ 15

Author(s):

Mladen Borovina ◽

Ivan Kodrin ◽

Marijana Đaković

Keyword(s):

Coordination Chemistry ◽

Electron Density ◽

Metal Cations ◽

Halogen Bonding ◽

Fine Tuning ◽

Halogen Bonds

To test the limit of halogen bonds fine-tuning of electron density was performedviaintroduction of heteroatoms and metal cations.

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Supramolecular organization of complexes of aryl hydrazones with SnCl3and SnCl4

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314093425 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C657-C657

Author(s):

Alexander Korlyukov ◽

Anna Vologzhanina ◽

Evgenia Voronova ◽

Natalia Shmatkova ◽

Inna Seifullina

Keyword(s):

Crystal Structures ◽

Electron Density ◽

Intermolecular Interactions ◽

Active Species ◽

Biologically Active ◽

Supramolecular Organization ◽

Halogen Bonds ◽

Covalent Interaction ◽

Theoretical Approaches ◽

Density Analysis

Chelate complexes of main group metals with N,O-chelating Schiff Base ligands have been reported as perspective models for biologically active species. The derivatives of aryl hydrazones are among the most widely used ligands of such type. In our study, crystal structures of aryl hydrazones with SnCl3and SnCl4are discussed: the presence of aromatic fragments, amine groups and chlorine atoms therein are responsible for the coexistence of strong hydrogen and halogen bonds as well as stacking and Cl...π interactions. Interplay between these types of interactions and their role in stabilization of crystal structures is the subject of particular interest. We studied all these aspects in complexes of aryl hydrazones using different theoretical approaches: those based on Stockholder partitioning, molecular electrostatic potential, non-covalent interaction index, AIM theory – together with Espinosa-Mollins-Lecomte correlation to estimate the energy of all intermolecular interactions in crystals by means of electron density analysis from periodic quantum chemical calculations (VASP code). Our results showed that the presence of intermolecular interactions led to a noticeable redistribution of electron density in crystal as compared to an isolated molecule. Although Cl...π, stacking interactions and halogen bonds are numerous in the crystals of these complexes, their contribution to the energy of their crystal lattice does not exceed 30%. The work was supported by Council of the President of the Russian Federation (grant MD-3589.2014.3).

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Halogen Bonding: A Halogen-Centered Noncovalent Interaction Yet to Be Understood

Inorganics ◽

10.3390/inorganics7030040 ◽

2019 ◽

Vol 7 (3) ◽

pp. 40 ◽

Cited By ~ 37

Author(s):

Pradeep Varadwaj ◽

Arpita Varadwaj ◽

Helder Marques

Keyword(s):

Electron Density ◽

Weak Interactions ◽

Early Recognition ◽

Noncovalent Interactions ◽

Covalent Bond ◽

Halogen Bonding ◽

Noncovalent Interaction ◽

Type I ◽

Type Ii ◽

Halogen Bonds

In addition to the underlying basic concepts and early recognition of halogen bonding, this paper reviews the conflicting views that consistently appear in the area of noncovalent interactions and the ability of covalently bonded halogen atoms in molecules to participate in noncovalent interactions that contribute to packing in the solid-state. It may be relatively straightforward to identify Type-II halogen bonding between atoms using the conceptual framework of σ-hole theory, especially when the interaction is linear and is formed between the axial positive region (σ-hole) on the halogen in one monomer and a negative site on a second interacting monomer. A σ-hole is an electron density deficient region on the halogen atom X opposite to the R–X covalent bond, where R is the remainder part of the molecule. However, it is not trivial to do so when secondary interactions are involved as the directionality of the interaction is significantly affected. We show, by providing some specific examples, that halogen bonds do not always follow the strict Type-II topology, and the occurrence of Type-I and -III halogen-centered contacts in crystals is very difficult to predict. In many instances, Type-I halogen-centered contacts appear simultaneously with Type-II halogen bonds. We employed the Independent Gradient Model, a recently proposed electron density approach for probing strong and weak interactions in molecular domains, to show that this is a very useful tool in unraveling the chemistry of halogen-assisted noncovalent interactions, especially in the weak bonding regime. Wherever possible, we have attempted to connect some of these results with those reported previously. Though useful for studying interactions of reasonable strength, IUPAC’s proposed “less than the sum of the van der Waals radii” criterion should not always be assumed as a necessary and sufficient feature to reveal weakly bound interactions, since in many crystals the attractive interaction happens to occur between the midpoint of a bond, or the junction region, and a positive or negative site.

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Methyl groups as widespread Lewis bases in noncovalent interactions

Nature Communications ◽

10.1038/s41467-021-25314-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Oliver Loveday ◽

Jorge Echeverría

Keyword(s):

Electron Density ◽

Lewis Acids ◽

Alkaline Earth ◽

Noncovalent Interactions ◽

Theoretical Calculations ◽

Methyl Groups ◽

Halogen Bonds ◽

Common Pattern ◽

Lewis Bases ◽

Significant Strength

AbstractIt is well known that, under certain conditions, C(sp3) atoms behave, via their σ-hole, as Lewis acids in tetrel bonding. Here, we show that methyl groups, when bound to atoms less electronegative than carbon, can counterintuitively participate in noncovalent interactions as electron density donors. Thousands of experimental structures are found in which methyl groups behave as Lewis bases to establish alkaline, alkaline earth, triel, tetrel, pnictogen, chalcogen and halogen bonds. Theoretical calculations confirm the high directionality and significant strength of the interactions that arise from a common pattern based on the electron density holes model. Moreover, despite the absence of lone pairs, methyl groups are able to transfer charge from σ bonding orbitals into empty orbitals of the electrophile to reinforce the attractive interaction.

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Electron-density studies of short intermolecular halogen bonds

Acta Crystallographica Section A Foundations of Crystallography ◽

10.1107/s0108767310093566 ◽

2010 ◽

Vol 66 (a1) ◽

pp. s282-s282

Author(s):

Ulli Englert ◽

Ruimin Wang ◽

Thomas Dols ◽

Christian W. Lehmann

Keyword(s):

Electron Density ◽

Halogen Bonds

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The many flavours of halogen bonds – message from experimental electron density and Raman spectroscopy

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s205322961901132x ◽

2019 ◽

Vol 75 (9) ◽

pp. 1190-1201 ◽

Cited By ~ 1

Author(s):

Ruimin Wang ◽

Janine George ◽

Shannon Kimberly Potts ◽

Marius Kremer ◽

Richard Dronskowski ◽

...

Keyword(s):

Critical Point ◽

Electron Density ◽

Halogen Bond ◽

Bond Distance ◽

Bond Critical Point ◽

Halogen Bonds ◽

Derived Properties ◽

The Many ◽

A Minor ◽

Experimental Electron Density

Experimental electron-density studies based on high-resolution diffraction experiments allow halogen bonds between heavy halogens to be classified. The topological properties of the electron density in Cl...Cl contacts vary smoothly as a function of the interaction distance. The situation is less straightforward for halogen bonds between iodine and small electronegative nucleophiles, such as nitrogen or oxygen, where the electron density in the bond critical point does not simply increase for shorter distances. The number of successful charge–density studies involving iodine is small, but at least individual examples for three cases have been observed. (a) Very short halogen bonds between electron-rich nucleophiles and heavy halogen atoms resemble three-centre–four-electron bonds, with a rather symmetric heavy halogen and without an appreciable σ hole. (b) For a narrow intermediate range of halogen bonds, the asymmetric electronic situation for the heavy halogen with a pronounced σ hole leads to rather low electron density in the (3,−1) critical point of the halogen bond; the properties of this bond critical point cannot fully describe the nature of the associated interaction. (c) For longer and presumably weaker contacts, the electron density in the halogen bond critical point is only to a minor extent reduced by the presence of the σ hole and hence may be higher than in the aforementioned case. In addition to the electron density and its derived properties, the halogen–carbon bond distance opposite to the σ hole and the Raman frequency for the associated vibration emerge as alternative criteria to gauge the halogen-bond strength. We find exceptionally long C—I distances for tetrafluorodiiodobenzene molecules in cocrystals with short halogen bonds and a significant red shift for their Raman vibrations.

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