摘要:

FT-IR spectroscopy studies on the adsorption of pyridine on silica-supported heteropolyanions have shown the presence of surface acid sites, both Lewis and Bronsted ones, when starting from commercial phosphomolybdic acid, but only Lewis acid sites when starting from nhexylammonium phosphododecamolybdate. A preferential formation of propene instead of acetone (i.e., a larger selectivity towards dehydration) has been observed during isopropanol decomposition, due to the strong surface acidity of the samples.

ISSN:0038-7010    

DOI:10.1080/00387019708006700

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A vibrational study of the local anesthetic procaine hydrochloride in the solid state and in aqueous solution was carried but. Assignment of the amino groups was performed using deuterated and non-deuterated samples. All the bands in the spectra were identified and assigned. The structure of the procaine cation was determined using the AM 1 semi-empirical method. A comparison with crystallographic data was made. The frequencies and intensities of the vibrations were also computed using AM1. Vibrational scale factors were employed in the AM1 calculations.

ISSN:0038-7010    

DOI:10.1080/00387019708006701

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The IR spectra have been recorded in the solid state for the parent molecule, 6-(N-pyrrolyl)purine (1) and itsN-9-andN-7-substituted derivatives: 9-and 7-(2-hydroxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (2and3), 9-and 7-(2-acetoxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (4and5), 9-and 7-(2,3-dihydroxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (6and7) as well as 9-and 7-(2,3-diacetoxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (8and9). Analysis of the characteristic bands has proved to be useful in differentiating betweenN-9 andN-7 regioisomers.

ISSN:0038-7010    

DOI:10.1080/00387019708006702

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The photoacouslic spcctra(PAS) of ternary complexes EuPhen2Sal3and TbPhen2Sal3are reported. Compared with the PA spectra of binary complexes, the change of PA relative intensities of salicylic acid(Sal) in ternary complexes indicates the different probabilities of nonradiative transitions and different relaxation processes. Combined with emission spectra the relaxation and energy transfer processes especially the interaction between two ligands are discussed.

ISSN:0038-7010    

DOI:10.1080/00387019708006703

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Steady state as well as time-resolved decay analysis techniques have been adopted to study the excited state proton transfer (ESPT) reaction of carbazole (CAZL) in three aqueous micellar solutions, namely, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and triton X-100 (TX) in the absence as well as in the presence of urea. For all the micellar systems studied, multiple critical micellar concentrations (CMCs) have been observed. Urea is found to inhibit the micellisation process. Light has been thrown on the mode of action of urea. It has also been shown that urea expels the fluorophore molecule from the micellar periphery to the bulk aqueous phase.

ISSN:0038-7010    

DOI:10.1080/00387019708006704

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The protonation of N-(4-X-phenylaminomethyl)-phthalimide derivatives and phthalimide in aqueous acidic (H2SO4) media was investigated, using the spectrophotometric method. These phthalimide derivatives have three protonation processes. The first protonation process occurs in pH range and belongs to the protonation of amino-group. The second and the third protonation process (occur in concentrated sulfuric acid solutions) are overlapping processes. They were separated by the modified method of separation (Garcia et al.). The protonation constants were calculated by Hammett and Cox-Yates method. The effect of chemical structure on ionisation constants is discussed.

ISSN:0038-7010    

DOI:10.1080/00387019708006705

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0038-7010    

DOI:10.1080/00387019708006706

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Absorption electronic spectra of MoO and WO molecules have been investigated by a intracavity laser technique in the region 550–800 run. New features have been discovered.

ISSN:0038-7010    

DOI:10.1080/00387019708006707

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Several methods for protein determination have been described. In almost all cases, a detection reagent is involved (Coomassie Blue reagent, bicinchoninic acid, Folin reagent). Proteins quantification determination by measurements in the U.V. region1have been abandonned because of the weak sensitivity of the apparatus (concentrations of the order of 100 μg/ml) and because of the lack of precision at low wavelengths (far U.V.).

ISSN:0038-7010    

DOI:10.1080/00387019708006708

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The semiempirical method AM1 was used to optimize the geometric parameters: bond lengths, bond angles and torsional angles in the local anesthetic benzocaine hydrochloride. The frequencies and intensities of the normal modes were computed. These results were compared with the infrared and Raman spectroscopic data. A theoretical spectrum using several scale coefficients was plotted. Electron density maps in two and three dimensions were drawn. Several calculated thermodynamic parameters are discussed.

ISSN:0038-7010    

DOI:10.1080/00387019708006709

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor