Density functional theory, in particular, with the Becke-3-parameter-Lee-Yang-Parr (B3LYP) hybrid functional, has been shown to be a promising method for the calculation of indirect nuclear spin-spin coupling constants. However, no systematic investigation has so far been undertaken to evaluate the capability of B3LYP to calculate these coupling constants accurately, taking properly into accoun...

having conducted fundamental projects, scientists have expressed their hope to develop the use of carbon nanotubes to release drugs. it is important to release drugs in cell without damaging healthy cells of tissues under study. researchers have shown the fact that nanotubes can perform this function perfectly. to this objective, in the present study the interactions between four anti-cancer dr...

we present detailed theoretical studies of the h-bonded complexes formed from interaction between 5-fluorouracil and various six-membered cyclic nitrosamine compounds. in this study, an investigation on intermolecular interactions in x-nu (x = ch2, sih2,bh, alh, nh, ph, o and s) complexes is carried out using density functional theory. the calculations are conducted on b3lyp/6-311++‏‏g** level ...

Force field parameters specifically optimized for residues important in the study of RNA catalysis are derived from density-functional calculations, in a fashion consistent with the CHARMM27 all-atom empirical force field. Parameters are presented for residues that model reactive RNA intermediates and transition state analogs, thio-substituted phosphates and phosphoranes, and bound Mg(2+) and d...

The vibrational spectroscopy of SO4 2− · H2O n is studied by theoretical calculations for n=1–5, and the results are compared with experiments for n=3–5. The calculations use both ab initio MP2 and DFT/B3LYP potential energy surfaces. Both harmonic and anharmonic calculations are reported, the latter with the CC-VSCF method. The main findings are the following: 1 With one exception H2O bending ...

Metal-free hydrogenation of imines by phosphonium borate zwitterion R2PH(CQF4)BH(C6F5)2 (1, R = CH3, tBu), has been studied by density functional theory (DFT) calculations. The study elucidates a two-step mechanism in which protonation of an imine by the phosphonium part of 1 is followed by hydride transfer to the C center from the borohydride part of 1. According to our calculations, the hydri...

Pathways for homogeneous thermal decomposition of (C2H5)3Ga (TEGa) were followed using in situ Raman spectroscopy measurements in an up-flow, cold-wall CVD reactor. The results of Density Functional Theory (DFT) calculations were used to assign measured Raman bands to the decomposition products (Et)3Ga, (DEGa)2, (Et)GaH–Ga(Et)2 and (Et)GaH–GaH2. The results of this study are consistent with bot...

Molecular docking and quantum chemistry calculations were used to establish the molecular model of β-cyclodextrin inclusion complex with five major compounds found in Thai sweet basil (Ocimum basilicum) essential oils, which includes linalool, eugenol, methyl eugenol, estragole, and eucalyptol. The electronic structures and the binding energies of 1:1 inclusion complexes of host:guest ratio for...

A new series of 2-amino-5-arylazothiazole derivatives has been designed and synthesized in 61-78% yields and screened as potential antibacterial drug candidates against the Gram negative bacterium Escherichia coli. The geometry of the title compounds were being studied using the Material Studio package and semi-core pseudopods calculations (dspp) were performed with the double numerica basis se...

The molecular vibrations of 1-Naphtol were investigated in polycrystalline sample, at room temperature, by FTIR and FT-Raman spectroscopy. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of 1-Naphtol . On the basis of B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations, a normal...