A σ-hole bond is a noncovalent interaction between covalently-bonded atom of Groups IV-VII and negative site, e.g. lone pair Lewis base or an anion. It involves region positive electrostatic potential, labeled σ-hole, on the extension one covalent bonds to atom. The due anisotropy atom's charge distribution. Halogen bonding subset interactions. Their features properties can be fully explained in terms electrostatics polarization plus dispersion. strengths interactions generally correlate...

A halogen bond is a highly directional, electrostatically-driven noncovalent interaction between region of positive electrostatic potential on the outer side X in molecule R–X and negative site B, such as lone pair Lewis base or π-electrons an unsaturated system. The corresponds to electronically-depleted lobe half-filled p-type orbital that involved forming covalent R. This depletion labeled σ-hole. resulting along extension bond, which accounts for directionality bonding. Positive σ-holes...

Abstract The electrostatic potential V ( r ) that is created by a system of nuclei and electrons formulated directly from Coulomb's law physical observable, which can be determined both experimentally computationally. When evaluated in the outer regions molecule, it shows how latter ‘seen’ an approaching reactant, thus useful guide to molecule's reactive behavior, especially noncovalent interactions. However, fundamental property system, significance goes beyond its role reactivity. For...

Abstract Halogen bonding is a noncovalent interaction that receiving rapidly increasing attention because of its significance in biological systems and importance the design new materials variety areas, for example, electronics, nonlinear optical activity, pharmaceuticals. The interactions can be understood terms electrostatics/polarization dispersion; they involve region positive electrostatic potential on covalently bonded halogen negative site, such as lone pair Lewis base. potential,...

Abstract Recent work by others has shown that the densities of C,H,N,O molecular crystals are, in many instances, given quite well formula M/Vm, which M is mass and Vm volume isolated gas phase molecule enclosed 0.001 au contour its electronic density. About 41% predictions were error less than 0.030 g/cm3, 63% 0.050 g/cm3. However, this leaves more one-third compounds with errors greater or some 0.100 This may indicate intermolecular interactions within crystal are not being adequately...

The average ionization energy, [Formula: see text], is introduced and demonstrated to be useful as a guide chemical reactivity in aromatic systems. text] rigorously defined within the framework of self-consistent-field molecular orbital (SCF-MO) theory can interpreted energy needed ionize an electron at any point space molecule. An abinitio SCF-MO approach has been used calculate 6-31G* level, using STO-3G optimized geometries. computed on surfaces by contour constant electronic density...

Using an ab initio self-consistent-field molecular orbital approach, we have computed 6-31G*//STO-3G* electrostatic potentials for CH3F, CF4, CH3Cl, CCl4, CH3Br, and CBr4. It is demonstrated that the along carbon–halogen bonds of these systems can explain observed directional preferences halogens' intermolecular interactions. Our surface chlorinated brominated molecules favor “side-on” “head-on” interactions with electrophiles nucleophiles, respectively, CCl CBr in crystals, whereas CH3F...

A covalently-bonded atom typically has a region of lower electronic density, “σ-hole,” on the side opposite to bond, approximately along its extension. There is often positive electrostatic potential (strongest shown in red) associated with σ-hole, although it may deviate from extension bond.

Abstract The electrostatic potentials computed on the surfaces of a series molecules R 3 X, where X is Group V atom, show that some these atoms have regions positive potential their outer surfaces, approximately extensions RX bonds. This suggests likelihood weak, directional noncovalent interactions between such and nucleophiles, paralleling what has already been established for Groups VI VII. origins relative strengths are explained in terms σ‐hole concept, supported by natural bond...

σ‐Holes and π‐holes are two types of regions lower electronic density that frequently found in molecules. There often positive electrostatic potentials associated with them, through which the molecule can interact attractively negative sites to form noncovalent bonds. The Hellmann–Feynman theorem shows these interactions Coulombic, where this must be understood include polarization as well electrostatics. Computed molecular have played major roles elucidating natures σ‐hole π‐hole bonding,...

Abstract In certain molecular environments, a covalently‐bonded atom from Groups V–VII may have region of significantly‐positive electrostatic potential on its outer side, along the extension covalent bond. This is due to electron‐deficient lobe half‐filled p bonding orbital, which called “σ‐hole.” σ‐Hole resulting highly directional noncovalent interaction that occur with nucleophile, e.g., lone pair Lewis base. this article, we compare computed energies and vibrational frequency shifts...

Halogen bonding is a unique type of noncovalent binding phenomenon in which halogen atom interacts attractively with an electronegative such as oxygen or nitrogen. These types interactions have been the subject many recent investigations because their potential development new materials and pharmaceutical compounds. Recently, it was observed that most biological contexts involve close contacts between bound to aromatic ring carbonyl on protein's backbone structure. In this work we...

Earlier work has shown a link—not necessarily causal relationship—between the impact sensitivities of energetic compounds and electrostatic potentials on their molecular surfaces. The latter are anomalous in that positive regions strikingly dominant, contrary to what is typical organic molecules. In this work, we show presence several electron-withdrawing NO2 groups and/or aza nitrogens (common features systems), which reason for anomalously surface potentials, also weakens C–NO2 N–NO2...