2-(2,4-Dimethylphenyl)-2H-benzotriazole (1) has been synthesized in a three step procedure starting from 2,4-dimethyl-N-(2-nitrophenyl)benzamide via a 5-(2,4- dimethylphenyl)-1-(2-nitrophenyl)-1H-tetrazole intermediate. Its structure and those of Tinuvin P and 2-phenyl-2H-benzotriazole (5) have been studied by multinuclear NMR (1H-, 13C- and 15N-) in solution and in the solid state. X-ray diffr...

Several modifications that have been made to the NDDO core-core interaction term and to the method of parameter optimization are described. These changes have resulted in a more complete parameter optimization, called PM6, which has, in turn, allowed 70 elements to be parameterized. The average unsigned error (AUE) between calculated and reference heats of formation for 4,492 species was 8.0 kc...

We have improved a modified charge equilibration (MQEq) method for calculating the geometry-dependent distribution of atomic charges. In this paper, Ohno-Klopman, Ohno and DasGupta-Huzinaga equations are adopted to express the shielding effect, and the calculated atomic charges with these MQEq methods are in good agreement with those by the HF/6-31G(d,p) calculations for several organic molecul...

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...

A number of significant structures NH3 (H2O) n (n= 1- 6) clusters have been identified by the quantum chemical methods ( RHF/3-21G, RHF/6-31G**, В3LYP/6-31G**, MP2/6-31G**). The cluster’s geometry configurations and intermolecular energy calculated

in the present study, theoretical chemical reactivates photo isomerization in cis-retinal as a natural photo switch in vision. dft hybrid functional, b3lyp and, post-hf method, were the theoretical methods applied utilizing g09 software. 6-31g+ (d,p) basis set employed for structural optimizations, and single point computations performed using b3lyp/6-31g+(d,p). the isomers cis molecule retinal...

hf level of ab initio calculations with basis-set 6-31g including full counterpoise correction hasbeen applied to compute the asphis potential with the ser and hisser potential with the asp inasphisser trimer. the potential energy surface has a minimum of -16.765 kcal/mol in r1=1.912nm and r2=2.719 nm. the optimum computed curves for two interactions were fitted withintermolecular pair potentia...

human immunodeficiency virus (hiv) infection is the major problem in the world. nowadays, new anti-retroviral drugs are extracted from medicinal plants, make an important role to supersede synthetic drugs with different side effects. in this study, we studied the salix aegyptiaca l extract, iranian herb, as an anti-hiv drug with anti-retroviral effects. we used a single cycle replicable (scr) h...

The reference electrophilicity and nucleophilicity scales established at the B3LYP/6-31G(d) level are herein extended by least squares regressions to most common DFT computational methods used in theoretical organic chemistry studies, including B3LYP, MPWB1K, M062-X, ωB97x-D, combination with basis sets of type 6-31G 6-311G different degrees polarization diffuse functions. Excellent linear corr...

The density functional theory (DFT) calculations at the level of B3LYP/6-31G was carried out on the structure 4(5)-Imidazole-carbaldehyde-N(5)-phenylthiosemicarbazone (ImTPh) in gas phase using Gaussian 03. Dipole moment (Debye), energy of structure formation (HF; kcal/mol) and point group, NMR parameters such as isotropic shielding (σiso) and anisotropic shielding (σaniso), σ11, σ22 and σ33 ob...