Quantum chemistry calculations have been performed to compute optimized geometry, Mulliken charges, harmonic vibrational frequency along with intensities in IR at HF/6-311++G(d,p) and B3LYP/6-311++G(d,p) level for N-(1,3,4-thiadiazol-2-yl)-1-[1-(6-chloropyridin-3-yl)methy]-5-methyl-1-H-[1,2,3]triazol-4-carboxamide (C12H10ClN7OS) in the ground state. Theoretical vibrational spectra of the title ...

Ab initio quantum chemical calculations, G3B3, second-order Møller– Plesset (MP2), and the hybrid density functional method B3LYP were employed to compute the proton affinities of 24 heterocyclic amines. A range of basis sets are employed, starting from doublepolarization quality to triplequality basis set with augmented diffuse and polarization function. Experimental values were used to calibr...

In this study the molecular geometries, experimental vibrational and electronic absorption spectra and quantum chemical calculations of free dimethyl phenylphosphonite, (C8H11PO2), (with synonym, dimethoxyphenylphosphine or phenyldimethoxyphosphine) (Abbreviated as DMPP) and its [Cd(DMPP)].Cl2.H2O metal halide complex have been investigated by using elemental analysis, FT-IR, micro-Raman and UV...

A rosane type diterpenoid has been isolated from the ethyl acetate soluble fraction of Stachys parviflora. The structure elucidation was based primarily on 1Dand 2D-NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY). Density functional theory...

Linear response and variational treatment are formulated for Hartree-Fock (HF) and Kohn-Sham density functional theory (DFT) methods and combined discrete-continuum solvation models that incorporate self-consistently induced dipoles and charges. Due to the variational treatment, analytic nuclear gradients can be evaluated efficiently for these discrete and continuum solvation models. The forces...

The performance of the Hartree-Fock method and the three density functionals B3LYP, PBE0, and CAM-B3LYP is compared to results based on the coupled cluster singles and doubles model in predictions of the solvatochromic effects on the vertical n-->pi* and pi-->pi* electronic excitation energies of acrolein. All electronic structure methods employed the same solvent model, which is based on the c...

Adiabatic ionization energy (AIE) calculations were performed at the AM1, PM3, PM6, PDDG, HF/QZVP, and B3LYP/QZVP levels of theory on 722 atmospherically relevant organic compounds with available experimental kOH . From the starting set of molecules, a final suite of 114 monoand polyfunctionalized compounds provided converged neutral and cationic geometries without imaginary frequencies for all...

Full geometric optimization of tricyclo[4.2.2.02,5]deca-3,7-diene (TDD) has been done by DFT/B3LYP methods and the structure of the molecule was investigated. Cyclobuten double bond (I) of molecule is syn pyramidalized, and bicyclookten double bond (II) is also exo pyramidalized. The double bond (I) is more pyramidalized than the double bond (II) and it has higher reactivity. The TDD-Br2 system...

Accurate (1)H chemical shifts of the -OH groups of polyphenol compounds can be calculated, compared to experimental values, using a combination of DFT, polarizable continuum model (PCM) and discrete solute-solvent hydrogen bond interactions. The study focuses on three molecular solutes: phenol, 4-methylcatechol and the natural product genkwanin in DMSO, acetone, acetonitrile, and chloroform. Ex...

Ab initio geometry optimization was carried out on 10 selected conformations of maltose and two 2-methoxytetrahydropyran conformations using the density functional denoted B3LYP combined with two basis sets. The 6-31G∗ and 6-311++G∗∗ basis sets make up the B3LYP/6-31G∗ and B3LYP/6-311++G∗∗ procedures. Internal coordinates were fully relaxed, and structures were gradient optimized at both levels...