Molecular structures, spectroscopic (FT-IR, NMR, UV) studies, NBO analysis and NLO properties for tautomeric forms of 1,3-dimethyl-5-(phenylazo)-6-aminouracil by density functional method.

The equilibrium geometry, nuclear magnetic resonance (NMR) and UV-Vis analysis, and vibrational frequencies for the azo and hydrazone isomers of 1,3-dimethyl-5-(phenylazo)-6-aminouracil have been performed using density functional theory (DFT/B3LYP) method with 6-311G(d,p) basis set. A detailed interpretation of the vibrational spectra has been made on the basis of the calculated potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA4) program. The H NMR chemical shifts with respect to TMS were calculated by the gauge independent atomic orbital (GIAO) method and compared with the experimental data.

Infrared Spectrum and UV-Induced Photochemistry of Matrix-Isolated 5-Hydroxyquinoline.

The structure, infrared spectrum, and photochemistry of 5-hydroxyquinoline (5HQ) were studied by matrix isolation infrared spectroscopy, complemented by theoretical calculations performed at the DFT(B3LYP)/6-311++G(d,p) level of approximation. According to the calculations, the trans conformer of 5HQ (with the OH group pointing to the opposite direction of the pyridine ring of the molecule) is more stable than the cis form (by ∼8.8 kJ mol(-1)).

FT-IR and FT-Raman spectra, molecular structure and first-order molecular hyperpolarizabilities of a potential antihistaminic drug, cyproheptadine HCl.

Cyproheptadine hydrochloride (CYP HCl) {4-(5H-dibenzo[a,d]-cyclohepten-5-ylidene)-1-methylpiperidine hydrochloride} is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local-anesthetic properties. The geometry optimization, Mulliken atomic charges and wavenumber and intensity of the vibrational bands of all of the possible modes of CYP HCl have been calculated using ab initio Hartree-Fock (HF) and density functional theory (DFT) employing the B3LYP functional with the 6-311G(d,p) basis set. We have compared the calculated IR and Raman wavenumbers with experimental data.

Experimental and theoretical investigations of 4-chloro-N-(2-methoxyphenyl)benzamidoxime.

4-Chloro-N-(2-methoxyphenyl) benzamidoxime (CMB) has been synthesized and characterized by X-ray diffraction, (1)H NMR, (13)C NMR, FT-IR and FT-Raman spectra. The X-ray study showed that CMB has a Z configuration, due to the strong intramolecular N-H···O hydrogen bond and centrosymmetric dimer form due to intermolecular O-H···N' and O-H···O' hydrogen bonds. The 2-methoxyphenyl and 4-chlorophenyl rings are twisted from the mean plane of the hydroxyamidine group by 33.

Molecular structure, FT-IR, FT-Raman, NMR studies and first order molecular hyperpolarizabilities by the DFT method of mirtazapine and its comparison with mianserin.

Mirtazapine (±)-1,2,3,4,10,14b-hexahydro-2-methylpyrazino(2,1-a)pyrido(2,3-c)(2)benzazepine is a compound with antidepressant therapeutic effects. It is the 6-aza derivative of the tetracyclic antidepressant mianserin (±)-2-methyl-1,2,3,4,10,14b-hexahydrodibenzo[c,f]pyrazino[1,2-a]azepine. The FT-IR and FT-Raman spectra of mirtazapine have been recorded in 4000-400 cm(-1) and 3500-10 cm(-1), respectively.

Study of the solvent effects on the molecular structure and CO stretching vibrations of flurbiprofen.

The effects of 15 solvents on the C=O stretching vibrational frequency of flurbiprofen (FBF) were determined to investigate solvent-solute interactions. Solvent effects on the geometry and C=O stretching vibrational frequency, ν(C=O), of FBF were studied theoretically at the DFT/B3LYP and HF level in combination with the polarizable continuum model and experimentally using attenuated total reflection infrared spectroscopy (ATR-IR). The calculated C=O stretching frequencies in the liquid phase are in agreement with experimental values.

Theoretical and vibrational studies of 4,5-diphenyl-2-2 oxazole propionic acid (oxaprozin).

The molecular structure, linear and nonlinear optical properties, and electronic properties of 4,5-diphenyl-2-2 oxazole propionic acid (oxaprozin) as a monomer were investigated by using Hartree-Fock (HF) and density functional theory (DFT) calculations that used 6-31G(d,p) basis set. The first-order hyperpolarizability of oxaprozin (OXA) was found to be 1.117 x 10(-30) esu.

Spectroscopic and DFT studies of flurbiprofen as dimer and its Cu(II) and Hg(II) complexes.

The vibrational study in the solid state of flurbiprofen and its Cu(II) and Hg(II) complexes was performed by IR and Raman spectroscopy. The changes observed between the IR and Raman spectra of the ligand and of the complexes allowed us to establish the coordination mode of the metal in both complexes. The comparative vibrational analysis of the free ligand and its complexes gave evidence that flurbiprofen binds metal (II) through the carboxylate oxygen.

Ab initio and density functional computations of the vibrational spectrum, molecular geometry and some molecular properties of the antidepressant drug sertraline (Zoloft) hydrochloride.

Sertraline hydrochloride is a highly potent and selective inhibitor of serotonin (5HT). It is a basic compound of pharmaceutical application for antidepressant treatment (brand name: Zoloft). Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, the atomic charges and polarizabilities were carried out.