Molecular surfaces at atomic and subatomic scales are inherently ill-defined. In many computational chemistry problems, interfaces are better represented as volumetric regions than as discrete surfaces. The geometry of this interface is largely defined by electron density and electrostatic potential fields. While experimental measurements such as chemical bond and Van der Waals radii do not dir...

2014 The orbital chemical shift of N.M.R., which measures the weight of non-s states in the chemical bond, can be related directly to the ionicity for tellurium compounds. In a molecular picture of the solid neglecting d states, the shift is a parabolic function of the number of p-electrons in the valence band. This number depends simply on the ionicity for tellurium bonds and can be modified b...

The concept of using single molecules as key building blocks for logic gates, diodes and transistors to perform basic functions of digital electronic devices at the molecular scale has been explored over the past decades. However, in addition to mimicking the basic functions of current silicon devices, molecules often possess unique properties that have no parallel in conventional materials and...

The structure of the ortho-, meta- and para- hybrid diindolylmethane-phenylboronic acids and their interactions were optimized with by a quantum chemical method, using density functional theory at the (DFT) level. Thus, infrared bands were assigned based on the scaled theoretical wavenumbers by correlating the respective experimental data of the molecules. In addition, the corresponding ¹H-/13C...

The nature of the intramolecular hydrogen bond in the enol tautomer of 2,4-pentanedione has been investigated by high resolution proton and deuteron magnetic resonance spectroscopy. An unusually large deuterium isotope effect on the chemical shift of the bridge hydrogen has been observed. This unexpected result, together with the observation of a pronounced temperature dependence for both the p...

We discussed the bonding of O2 to hemoglobin using results of ab initio calculations of idealized portions of the Hb molecule. The bond between Fe and O2 is formed by coupling a triplet state (intermediate spin state) of Fe to the triplet ground state of O2 (analogous to the bonding of O to O2 in ozone). The coordination sphere of the Fe reduces the energy separation between the quintet, triple...

The title compound, C(29)H(19)F(6)NOS(2), is a new unsymmetrical photochromic diarylethene derivative with different meta-phenyl substituents. The distance between the two reactive (i.e. can be irradiated to form a new chemical bond) C atoms is 3.501 (4) Å; the dihedral angles between the mean plane of the main central cyclo-pentene ring and the thio-phene rings are 47.7 (5) and 45.1 (2)°, and ...

We have studied the effect of different chemical bonding structures of boron atoms on the second-order nonlinear optical behavior of borate crystals from the chemical bond viewpoint. Several typical borate crystals, including LiB3O5, b-BaB2O4, BiB3O6, NdAl3(BO3)4, Ca4LnO(BO3)3, K[B5O6(OH)4]·2H2O, Eu2B5O9Cl and Ca2B5O9Br, with different chemical bonding structures of boron atoms are investigated...

Weisberg’s 2007 recent paper on the chemical bond makes the claim that the chemical notion of the covalent bond is in trouble. This note casts doubts on that claim.

Graphene nanostructures, where quantum confinement opens an energy gap in the band structure, hold promise for future electronic devices. To realize the full potential of these materials, atomic-scale control over the contacts to graphene and the graphene nanostructure forming the active part of the device is required. The contacts should have a high transmission and yet not modify the electron...