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

Author(s): Tao-Nhân V Nguyen

The structural and thermodynamic properties of Na+(CH3CN)n, I-(CH3CN)n, and NaI(CH3CN)n clusters have been investigated by means of room-temperature Monte Carlo simulations with model potentials developed to reproduce the properties of small clusters predicted by quantum chemistry. Ions are found to adopt an interior solvation shell structure, with a firs ...

Article GUID: 18183958

Author(s): Denise M Koch

Sodium iodide has long been a paradigm for ionic and covalent curve crossing and ultrafast nonadiabatic dynamics, and our interest lies in the influence of solvation on this process. The NaI(H2O)n photodissociation dynamics are simulated with the molecular dynamics with quantum transitions method. A quantum mechanics/molecular mechanics (QM/MM) descriptio ...

Article GUID: 18183959

Author(s): Qadir K Timerghazin

High-level ab initio calculations employing the CCSD and CCSD(T) coupled cluster methods with a series of systematically convergent correlation-consistent basis sets have been performed to obtain accurate molecular geometry and energetic properties of the simplest S-nitrosothiol (RSNO), HSNO. The properties of the S-N bond, which are central to the physio ...

Article GUID: 18327309

Author(s): Heidi M Muchall

We are presenting a computational study on the isotropic shielding, charge, and orbital contributions to the shielding of oxygen in benzaldehydes (Ar-CHO), nitrobenzenes (Ar-NO2), phenyl isocyanates (Ar-NCO), anilides (Ar-NHCOCH3), and N-sulfinylamines (Ar-NSO). In particular, changes upon ortho substitution of the aromatic ring and upon torsion of the un ...

Article GUID: 18754608

Author(s): Kamya PR; Muchall HM;

We have evaluated the performance of three (TD-)DFT functionals with the 6-31+G(d,p) basis set for the reproduction of experimental geometries, vertical ionization potentials, and low excitation energies of a selection of [2.2] and [3.3]paracyclophanes. Overall, (TD-)BH& H outperforms both (TD-)B3LYP and (TD-)PBE0. Some shortcomings are shown by B3LYP ...

Article GUID: 19055395