Nine isomers of Ge6, Ge6 , Ge6 , and Ge6 6have been searched for by the MP2/6-31+G(d), B3LYP/6-311+G(d), and B3LYP/ LANL2DZ electronic structure calculations. Totally 16 isomers are found: six Ge6, three Ge6 , five Ge6 , and two Ge6 . We discovered that the predicted stable shapes of Ge6 , Ge6 , and Ge6 6are octahedral, pentagonal pyramidal, and hexagonal, respectively, which agrees well with t...

N,N-dioctyl-azepanium, -piperidinium and -pyrrolidinium bromides 1-3, have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by B3LYP/6-31G(d,p) approach have been presented. Both FTIR and Raman spectra of 1-3 are consistent with the calculated structures in the gas pha...

Density functional theory calculations (DFT), as well as hybrid methods (B3LYP) for Bi8N18-[CoF6]3- complexhave been carried out to study the non-bonded interaction. The geometry of the 1313N18 has been optimized atB3LYP method with EPR-II basis set and geometry of the [CoF6]3 have been optimized at B3LYP method withDe12-TZVP basis set and Stuttgart RSC 1997 Effective Core Potential. The electr...

We have performed periodic density functional and periodic local MP2 calculations for the adsorption of hydrogen fluoride and water on the four low index surfaces (001), (100), (101) and (110) of magnesium fluoride. While the adsorption of HF is described well using B3LYP, MP2 is required for a good description of the adsorption of H2O. Post-optimization dispersion corrections of B3LYP are foun...

The catalytic asymmetric thiazolium- and triazolium-catalyzed benzoin condensations of aldehydes and ketones were studied with computational methods. Transition-state geometries were optimized by using Morokuma's IMOMO [integrated MO (molecular orbital) + MO method] variation of ONIOM (n-layered integrated molecular orbital method) with a combination of B3LYP/6-31G(d) and AM1 levels of theory, ...

Geometry optimizations of all cluster models were carried out in solution with Integral Equation Formalism Polarizable Continuum Model (IEFPCM) as implemented in Gaussian09. The B3LYP functional in conjunction with the 6-31+g(d) basis set was employed to optimize the geometries. Frequency calculations at the same level of theory were carried out to verify the nature of the stationary points enc...

Electrophilic triethylsilylation of diphenylketene leads to exclusive C-silylation giving the diphenyl(triethylsilyl)acetyl cation in the solution phase even though density functional theory calculations at the B3LYP/6-311+G* level indicate that the O-silylation of diphenylketene is preferred over C-silylation by 5.4 kcal/mol in the gas phase. On the other hand, in the case of the parent ketene...

Ab initio molecular orbital calculations on the interaction between Copper(I) and 5-nitrotetrazolate anion were done using different basis sets, at the HF, B3LYP and MP2 levels of theory. Three minima were found to 1A, 1B and IC structures of Cu(I)-5-NTz complex. At the B3LYP/LanL2DZ level, the energy difference between 1A and 1B was computed to be 8.18 kcal/mol, while that between 1A and 1C is...

Tripeptide Tyr-Aaa-Gly (1a, 2b) is methionine-enkephalin analogues [Aaa = (R,S)-(1adamantyl)glycine]. The unique structure of adamantane is reflected in its highly unusual physical and chemical properties, which can have many applications including drug design and drug delivery. In this research, Quantum-mechanical calculations were performed at the HF/6-31G, HF/6-31G*, B3LYP/6-31G, B3LYP/6-31+...

In this paper, we evaluate semiempirical methods (AM1, PM3, and ZINDO), HF and DFT (B3LYP) in different basis sets to determine which method best describes the sign and magnitude of the geometrical parameters of artemisinin in the region of the endoperoxide ring compared to crystallographic data. We also classify these methods using statistical analysis. The results of PCA were based on three m...