摘要:

Methyl groups in positions 2 and 6 of pyridine ring shift the long-wavelength band in the spectra of 3-substituted 1-(4′-dimethylaminobenzylideneamino) pyridinium salts towards shorter waves. The intensity of that band depends on nature of the substituent for 2-methyl derivatives, whereas a little hyperchromic effect was observed for the compounds carrying 6-methyl group. Linear dependencies were found between the band parameters and [sgrave] Hammett constants. Substituent effects on the band position in the spectra of 2-methyl-3-substituted compounds were weakened by the methyl groups present. It does not interact sterically with the substituent in position 3 of the pyridine ring.

ISSN:0038-7010    

DOI:10.1080/00387019208018202

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

IR spectroscopic method for determination of zeolite deposited on textiles after washing with zeolite containing detergents has been developed. The total inorganic deposits on the textiles were determined as percentual contents of textile ashes according to DIN 44983. Zeolite contents in the ash were determined by IR method, using as a standard additive zeolite thermally treated at 1073K for 2h. Calibration diagram was obtained by measuring band intensity atv=680 cm−1of the standard in ash samples with known standard contents. Comparative analysis has shown good agreement between the results obtained by the proposed method and chemical analysis of ashes. Repeated determination of zeolite contents in the same sample has shown good reproducibility and reliability of the method.

ISSN:0038-7010    

DOI:10.1080/00387019208018203

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Previous works on the molecular vibrations of C60buckminsterfullerene are reviewed briefly. Here both the theoretical and experimental works are taken into account. New calculations of mean amplitudes of vibration and related quantities for12C60are reported. These results are of great interest in the gas electron diffraction investigation of this molecule. The corresponding data are also given for13C60isotopic buckminsterfullerene.

ISSN:0038-7010    

DOI:10.1080/00387019208018204

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The infrared spectra of protiated and deuterated lead(II) saccharinate monohydrate, Pb(C7H4NO3S)2·H2O were studied in the OH, OD, CO and SO2stretching regions. The spectral characteristics of the HOH and HOD stretching fundamentals were correlated with the structural data on the geometry of the water molecules. Also correlated were the appearance of the spectrum in the CO stretching region, on the one hand, and the number of non-equivalent carbonyl groups in the structure, on the other. An attempt was made to assign the bands which are mainly due to the antisymmetric and the symmetric SO2stretching vibrations.

ISSN:0038-7010    

DOI:10.1080/00387019208018205

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Optimization of lead hydride generation has been performed and a regression model of the efficiency (chemical yield, E %) of plumbane generation has been derived from experimental data. The effect of various chemical and instrumental parameters on hydride generation and trapping in an absorbing solution of Ce(IV)-KI, with subsequent determination of lead by graphite-furnace atomic absorption spectrometry (GF-AAS) has been studied, in an effort to optimize conditions for preconcentration and determination of nanogram amount of lead. Characteristic concentrations are 1 μg/1 in absorbing solution and 0.2 μg/1 in a 50-ml aliquot of sample solution and the corresponding limits of detection are ca. 4 and 1 μg/1, respectively.

ISSN:0038-7010    

DOI:10.1080/00387019208018206

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This is a report on31P nmr spectra of phosphoric acid monodecylester, PDE, and2H quadrupolar splitting of D2O in a lyomesophase developed from n-decylammonium chloride, PDE/H3PO4and D2O.Polarizing microcopic and2H nmr studies showed that the mesophase was of lamellar-like structure but alignes as the temperature is increased. As the mesophase contained a minute amount of free H3PO4, the31P nmr spectra gave a sharp peak and a hump. The latter was interpreted to arise from a slow tumbling process of PDE between different agglomerates in this system.

ISSN:0038-7010    

DOI:10.1080/00387019208018207

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Adsorption of the drug N-methyl 8-hydroxy quinoline methyl sulphate, used to prevent sunburning and to avoid the dangerous effect of erythematogenic radiations, on untreated and HCl-treated sepiolite has been studied. The adsorption complex formed extends the absorption properties of the drug in the visible and ultraviolet range. The behaviour shown by these samples is fairly similar in all cases with respect to light absorption. However, adsorption complexes prepared via a dry method, by mechanically mixing the drug and sepiolite, lead to samples with different light absorbent properties, due to the modification of the surface acid/base properties of the sepiolite and hence of the way the drug is adsorbed.

ISSN:0038-7010    

DOI:10.1080/00387019208018208

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A complete vibrationalassignment of the title compounds is performed from their IR and Raman Spectra. A normal coordinate treatment of these molecules based on a simplified model allow us to confirm most of the experimental assignments.

ISSN:0038-7010    

DOI:10.1080/00387019208018209

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We have recorded part of the UV-visible region of the electronic spectrum of EuOCl at both 292 and 77 K by diffuse reflectance spectroscopy. Illumination of the sample and collection of the reflected light was accomplished through the use of an all-quartz fiberoptic probe. Several absorption maxima were observed which result from transitions from the7F0ground state and7F1excited state to the5D45G2,4,65L6, and5D3excited states of the Eu3+ion.

ISSN:0038-7010    

DOI:10.1080/00387019208018210

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A spectrophotometric stability—indicating method is presented for the determination of famotidine in the presence of its degradation products. The method is based on measuring the peak height of the second—derivative maximum at 304 nm. The proposed method is used for the analysis of famotidine in its pharmaceutical dosage forms. The results obtained were precise and accurate.

ISSN:0038-7010    

DOI:10.1080/00387019208018211

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor