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Potential Energy Surface (PES) scan of gas-phase L-proline

El Guerdaoui A., El Kahoui Y., Bourjila M., Tijar R., El Gridani A.

International Letters of Chemistry, Physics and Astronomy

2014

Vol. 19, iss. 1

26--34

We performed here a systematic ab initio calculations on neutral gas-phase L-proline. A total of 8 local minima were located by geometry optimization of the trial structures using density functional theory (DFT) with B3LYP three parameter hybrid potential coupled with the 6-31G)d( basis set. The absolute minimum obtained will be subject to a rigid potential energy surface (PES) scan by rotating its carboxylic group using the same method with more accurate basis set B3LYP/6-311++G(d,p), to get a deeper idea about its conformational stability. The main aim of the present work was the study of the rigidity of the L-proline structure and the puckering of its pyrrolidine ring.

Neutron Spectroscopy, IR, Raman and Ab Initio Study of L-Proline

Pawlukojc A., Leciejewicz J., Natkaniec I., Nowicka-Scheibe J.

Polish Journal of Chemistry

2003

Vol. 77 / nr 1

75-85

Inelastic incoherent neutron scattering spectra (IINS) were obtained for normal and deuterated L-proline. Raman and infrared spectra were also recorded. Geometries were optimized for the zwitterion form using ab initio Hartree-Fock (HF) level with 6-31G*, 6-311G** and 6-311++G** basis sets. Force fields and normal modes were calculated and used as basis for an assignment of the spectral features. The theoretical frequencies of normal and d2 - L-proline were compared with IINS spectra.

Kinetics and Mechanism of Oxidative Degradation of L-Proline by Alkaline Diperiodatonickelate(IV)- A Free Radical Intervention and Decarboxylation

Mulla R., Gurubasavaraj H., Nandibewoor S.

Polish Journal of Chemistry

2003

Vol. 77 / nr 12

1833-1840

The kinetics of oxidation of L-proline by diperiodatonickelate(IV) (DPN) in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm-3 was studied spectrophotometrically. The reaction is of first order in [DPN], zero order in [alkali] and less than unit order in [L-proline]. Addition of periodate has no effect on the rate of reaction. Effect of added products, ionic strength and dielectric constant of the reaction medium have been investigated. The main products were identified by spot test and IR spectra.Amechanism involving the diperiodatonickelate(IV) (DPN) as the reactive species of the oxidant has been proposed. The reaction constants involved in the different steps of mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated. The isokinetic temperature was determined and discussed.