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41.
German Urbina-Villalba Estrella Rogel Maria Lupe Márquez Isaac Reif 《Journal of computer-aided molecular design》1994,8(3):273-282
Summary The semiempirical MNDO method has been used in order to examine the variation of the molecular properties of hydrocarbons CnH2n+2 (with 1n19) and ethylene oxide chains CH3(CH2CH2O)mCH3 (with 1m19) as a function of their molecular length. Least-square fits of those properties have been calculated, along with two mathematical relations between the hydrophile-lipophile balance of alkyl-phenol ethoxylated surfactants and (1) the ratio of molecular lengths between their lipophilic and hydrophilic branches; (2) the intermolecular energies between the molecules of surfactant, water and hexane. 相似文献
42.
Roque Bru Jose M. López-Nicolás Estrella Núñez-Delicado Dolores Nortes-Ruipérez Alvaro Sánchez-Ferrer Francisco Garciá-Carmona 《Applied biochemistry and biotechnology》1996,61(1-2):189-198
The capability of cyclodextrins to enhance greatly the solubility in water of poorly water-soluble substances makes them an
ideal alter native for investigating the expression of enzyme activity with such substrates in aqueous solution. This capability
is demonstrated by using soybean lipoxygenase with linoleic acid/β-cyclodextrin and di ethylstilbestrol/γ-cyclodextrin, and
cholesterol oxidase with choles terol/methyl-β-cyclodextrin. 相似文献
43.
Summary The use of capillary electrophoresis for the analysis of selected flavonols present in fruit juices and wines (kaempferol-3-rutinoside,
rutin, avicularin, quercitrin, isoquercitrin, isorhamnetin, kaempferol and quercetin) was explored, and the effect of pH and
temperature on the separation studied. The method had good reproducibility and analyses were carried out in less than 10 minutes. 相似文献
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Ferran Sanz Francesc Manaut Jesús Rodríguez Estrella Lozoya Elena López-de-Briñas 《Journal of computer-aided molecular design》1993,7(3):337-347
Summary MEPSIM is a computational system which allows an integrated computation, analysis, and comparison of molecular electrostatic potential (MEP) distributions. It includes several modules. Module MEPPLA supplies MEP values for the points of a grid defined on a plane which is specified by a set of three points. The results of this program can easily be converted into MEP maps using third-parties graphical software. Module MEPMIN allows to find automatically the MEP minima of a molecular system. It supplies the cartesian coordinates of these minima, their values, and all the geometrical relationships between them (distances, angles, and dihedral angles). Module MEPCOMP computes a similarity coefficient between the MEP distributions of two molecules and finds their relative position that maximizes the similarity. Module MEPCONF performs the same process as MEPCOMP, considering not only the relative position of both molecules but also a conformational degree of freedom of one of them. The most recently developed module, MEPPAR, is another modification of MEPCOMP in order to compute the MEP similarity between two molecules, but only taking into account a particular plane. The latter module is particularly useful to compare MEP distributions generated by systems of aromatic rings. MEPSIM can use several wavefunction computation approaches to obtain MEP distributions. MEPSIM has a menu type interface to simplify the following tasks: creation of input files from output files of external programs (GAUSSIAN and AMPAC/MOPAC), setting the parameters for the current computation, and submitting jobs to the batch queues of the computer. MEPSIM has been coded in FORTRAN and its current version runs on VMS/VAX computers. 相似文献
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Estefanía del Horno Dr. Jesús Jover Dr. Miguel Mena Dr. Adrián Pérez-Redondo Dr. Carlos Yélamos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7096-7100
Titanium(III) complexes containing unprecedented (NH2BH2NHBH3)2− and {N(BH3)3}3− ligands have been isolated, and their structures elucidated by a combination of experimental and theoretical methods. The treatment of the trimethyl derivative [TiCp*Me3] (Cp*=η5-C5Me5) with NH3BH3 (3 equiv) at room temperature gives the paramagnetic dinuclear complex [{TiCp*(NH2BH3)}2(μ-NH2BH2NHBH3)], which at 80 °C leads to the trinuclear hydride derivative [{TiCp*(μ-H)}3{μ3-N(BH3)3}]. The bonding modes of the anionic BN fragments in those complexes, as well as the dimethylaminoborane group trapped on the analogous trinuclear [{TiCp*(μ-H)}3(μ3-H)(μ3-NMe2BH2)], have been studied by X-ray crystallography and density functional theory (DFT) calculations. 相似文献
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Structural and thermal properties of all-trans lycopene are described in the present paper. Different crystalline lycopene samples obtained from fermentation process and recrystallized lycopene were analyzed. Structural properties (NMR, mass spectrometry and powder X-ray diffraction) of lycopene were clarified with recent techniques. High purity sample analysis by differential scanning calorimetry was used to study thermal behavior of pure lycopene and with traces of isomers. But also this was correlated with HPLC method for determine lycopene purity and isomers in low proportion. 相似文献