The extensive computation study was done to elucidate the mechanism of formation dibromoepoxide from cyclohexanone and bromoform. In this reaction, the formation of dihaloepoxide 2 is postulated as a key step that determines the distribution and stereochemistry of products. Two mechanistic paths of reaction were investigated: the addition of dibromocarbene to carbonyl group of ketone, and the a...

Rigorously continuous and smooth potential energy surfaces, as well as exact analytic gradients, are obtained for a conductorlike screening solvation model (CPCM, a variant of the general COSMO) with Hartree-Fock (RHF, ROHF, UHF, and MCSCF) and density functional theory (R-DFT, RO-DFT, and U-DFT) methods using a new tessellation scheme, fixed points with variable areas (FIXPVA). In FIXPVA, sphe...

The protolytic dissociation process of hydrochloric acid (HCl) and hydrofluoric acid (HF) is studied using the B3LYP and MP2 methods with the 6-311+G(d,p) basis set in the gas phase and in aqueous solution. To study the phenomena in detail, discrete and discrete/continuum models were applied by placing water molecules in various positions around the acid. The dissociation process was studied us...

В данной работе представлены результаты компьютерного моделирования реакции переиминирования 1,2-дитрет-бутилэтандиимина в среде водного ацетонитрила с образованием 2,4,6,8,10,12-гексаацетил-2,4,6,8,10,12-гексаазатетрацикло-[5,5,0,03,11,05,9]додекана. На уровне теории функционала плотности использованием BP86 и базисного набора def2-SVP был смоделирован предположительный механизм континуальной ...

ONIOM calculation is carried out to estimate the acidity of five aliphatic alcohols before and after adsorbing on the tip of (8,0) single-walled carbon nanotube. The ONIOM method is performed using a combination of density functional theory and AM1 semiemperical method for alcohols and their corresponding conjugated bases. Deprotonation Gibbs free energies of alcohols are calculated and compare...

Nickel pyridine 2-thiolate (Ni(PyS)3(-)) has shown good stability and activity as a H2 generation catalyst for use in solar energy storage. The experimentally proposed catalytic pathway is explored using DFT calculations. Free energy changes along the reaction coordinate, spin states, localization of charge and geometry of the intermediates were explored. Calculations were performed using Gauss...

Density functional calculations of thio effects on the in-line mechanism of methanolysis of ethylene phosphate (a reverse reaction model for RNA phosphate transesterification) are presented. A total of 12 reaction mechanisms are examined using the B3LYP functional with large basis sets, and the effects of solvation were treated using the PCM, CPCM, and SM5 solvation models. Single thio substitu...

By using density functional theory (DFT) in B3LYP/6-311++G(d, p) level of theory and conductor-like polarizable continuum modem (CPCM) we examined solvent effects on energy levels in C 5 H 4 for both singlet and triplet states. For this purpose, different solvents, such as gaseous and aqueous solvents, Diethyl ether, Nitro methane, DMSO, Acetonitrile, Methanol, Ethanol, Acetone, Dichloroethane,...

Geothermal energy piles are a quite recent renewable energy technique where geothermal energy in the foundation of a building is used to transport and store geothermal energy. In this paper, a structural-functional integrated cement-based composite, which can be used for energy piles, was developed using expanded graphite and graphite nanoplatelet-based composite phase change materials (CPCMs)....

High-level ab initio molecular orbital theory is used to obtain benchmark values for the ferricenium/ferrocene (Fc(+)/Fc) couple, the IUPAC recommended reference electrode for nonaqueous solution. The gas-phase ionization energy of ferrocene is calculated using the high-level composite method, G3(MP2)-RAD, and two higher-level variants of this method. These latter methods incorporate correction...