Author(s): Paul G Loncke

Substituent effects and the role of negative hyperconjugation in 1,2-silyl migration and decarbonylation of methoxy(substituted-siloxy)carbenes have been investigated using quantum chemical calculations and natural bond orbital analysis. It has been found that sigma-electron-withdrawing substituents generally lower the barriers for 1,2-silyl migration and ...

Article GUID: 15917909

Author(s): Lei Zhang

Vertical excitation energies for electronic transitions from the ground state to the first two excited states of phenol, mono- and disubstituted methoxyphenols and methyl-substituted phenols have been characterized with the Time-Dependent Density Functional Theory (TD-DFT), the Complete Active Space Self-Consistent Field method (CASSCF) and the Coupled Cl ...

Article GUID: 16313201

Author(s): Denise M Koch

We have investigated the photodissociation dynamics of NaI(H(2)O)(n) [n = 1-4] clusters using the molecular dynamics with quantum transitions method and a quantum mechanics/molecular mechanics description of NaI(H(2)O)(n), which involves a semiempirical valence-bond approach to describe the NaI electronic structure and classical solvent-solvent and solute ...

Article GUID: 16435804

Author(s): Pascal Larrégaray

The unimolecular dissociation dynamics of aluminum clusters following collision with either a rare gas atom or a surface is investigated by classical trajectory simulations with model potentials. Two conformers of Al(6) with very distinct shapes, i.e., the spherical O(h) and planar C(2)(h) clusters, are considered in this work. The initial vibrational ene ...

Article GUID: 16435829

Author(s): Qadir K Timerghazin

High-level ab initio calculations employing the multireference configuration interaction and coupled clusters methods with a correlation-consistent sequence of basis sets have been used to obtain accurate potential energy curves for the complex of the sodium cation with the iodine atom. Potential curves for the first two electronic Lambda-S states have ve ...

Article GUID: 16438589

Author(s): Grygoriy Dolgonos

The potential stabilization of normally unstable C20, the smallest fullerene, via its encapsulation inside a tetraureacalix[4]arene dimer has been analyzed using molecular mechanics calculations with different force fields, the self-consistent-charge density-functional tight-binding with dispersion correction (SCC-DFTB-D) model, and standard density-funct ...

Article GUID: 16869690

Author(s): Grygoriy A Dolgonos

The C2 fragmentation energies of the most stable isolated-pentagon-rule (IPR) isomers of the C80 and C82 fullerenes were evaluated with second-order Møller-Plesset (MP2) theory, density-functional theory (DFT) and the semiempirical self-consistent charge density-functional tight-binding (SCC-DFTB) method. Zero-point energy, ionization energy and empirical ...

Article GUID: 17588181

Author(s): Qadir K Timerghazin

A resonance representation of the electronic structure of S-nitrosothiols as a combination of the conventional R-S-N=O structure, a zwitterionic structure R-S+=N-O-, and a RS-/NO+ ion pair is proposed. The resonance forms are employed to predict and rationalize the structural and conformational properties of RSNOs, their interaction with Lewis acids, and ...

Article GUID: 17616141

Author(s): Qadir K Timerghazin

Two or more polar molecules can trap an excess electron either in a dipole-bound fashion where it is located outside of the cluster (dipole-bound electron) or inside the cluster (solvated electron). The topology of the electron density in dipole-bound and solvated-electron clusters has been examined for the paradigm (HF)3- cluster. As spatial confinement ...

Article GUID: 17705589

Author(s): Elena V Ivanova

A comparative study of the concerted hydrolysis of H-, CF3-, CH3-, and Ph-substituted N-sulfinylamines (R-NSO) and isocyanates (R-NCO) was performed using B3LYP/6-31+G(2d,2p). The "two-water-molecule" model was found to be sufficient for a proper description of the hydrolysis reaction for both classes of compounds. Despite their overall similar reactivity ...

Article GUID: 17915846

Author(s): Robert C Mawhinney

The 13C chemical shifts in selected nitrilimines, nitriles, acetylenes, allenes, and singlet carbenes have been calculated using density-functional theory [PBE0/6-311++G(2df,pd)] and the gauge including atomic orbital (GIAO) method. The effects of substitution on the 13C chemical shifts in nitrilimines, R1-CNN-R2, have been examined. The carbon nucleus is ...

Article GUID: 18062684

Author(s): Qadir K Timerghazin

Acetonitrile molecules are known for their intriguing ability to accommodate an excess electron in either a diffuse dipole-bound orbital, away from the valence electrons, or in its valence orbitals, depending on the environment. In this work, we report a computational investigation of the monomer and dimer acetonitrile anions, with the main goal of gainin ...

Article GUID: 18154288