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...

The specific optical rotation of (S)-fluoro-oxirane in gas phase and solution is predicted using time-dependent density functional theory (B3LYP functional) and coupled cluster linear response theory. Upon vibrational averaging, the coupled cluster singles and doubles model predicts the gas phase specific optical rotation to be 8.1 degrees (dm g/cm(3))(-1) at 355 nm at room temperature. This 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+...

Employing introductory (3-21G RHF) and medium-size (6-311++G∗∗ B3LYP) ab initio calculations, complete conformational libraries, containing as many as 27 conformers, have been determined for diamide model systems incorporating the amino acids valine (Val) and phenylalanine (Phe). Conformational and energetic properties of these libraries were analyzed. For example, significant correlation was f...

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...

Molecular interaction between perthiolated [beta]-cyclodextrin (CD) and the guests molecules adamantaneacetic acid (AD) and ferroceneacetic acid (FC); and the effect of the interaction on the electron transition of CD anchored particles Ning, Ming, "Molecular interaction between perthiolated [beta]-cyclodextrin (CD) and the guests molecules adamantaneacetic acid (AD) and ferroceneacetic acid (F...

Basicity constants for a series of 3,7-diazabicyclo[3.3.1]nonane derivatives in acetonitrile with a variation over 13 orders of magnitude have been determined using a spectrophotometric titration technique. An excellent correlation between basicity and calculated proton affinities obtained at PCM-B3LYP/6-31+G(d)//B3LYP/6-31G(d) level was found. The results are discussed in terms of substituent ...

A series of monocyclic planar inorganic compounds have been optimized at the B3LYP/6-311+G* level. GIAO-B3LYP nucleus-independent chemical shifts (NICS) profiles calculated in the perpendicular direction of each ring show that the series of analyzed compounds can be classified in three groups according to their aromatic, non-aromatic or antiaromatic character. Our results suggest exercising cau...

FT-IR and FT-Raman spectra of 2-phenyl-4H-3,1-benzoxazin-4-one were recorded and analyzed. The vibrational wavenumbers of the title compound have been computed using the HartreeFock and B3LYP levels of theory using 6-31G* basis set and compared with the experimental data. The results indicate that B3LYP calculations approximate the observed fundamental wavenumbers much better than the HF result...

The electronic and geometric structures of endo,endo-tetracyclo[4.2.1.1.0] dodeca-4,9-diene(TTDD) molecule have been investigated by ab initio and DFT/B3LYP methods with the 6-31G* and 6-311G* basis sets. The double bonds of TTDD molecule have been endo-pyramidalized. The structure of π-orbitals and their mutual interactions for TTDD molecule have been investigated. The cationic intermediates a...