摘要:

A simple spectrophotometric method for the determination of niclosamide in pure and dosage forms has been developed. The proposed method is based on the reduction of the nitro group in niclosamide to the amino group by heating in a water bath a mixture of niclosamide solution in 95% ethanol, zinc powder and dilute hydrochloric acid for 15 minutes. The cold and clear filtrate reacts with p-benzoguinone, where a compound of pink colour is obtained which absorbs maximally at 506 nm.

ISSN:0038-7010    

DOI:10.1080/00387019708001628

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

In this work a general method for analysis of the d-d transition energies is used to derive the angular overlap model (AOM) parameters of chromium(III) complexes with C2vsymmetry. It allows investigation of various complexes in solutions with low symmetries (cis-[MX2(LL)2], LL = bidentate ligand) and different π-bonding abilities of ligands. Successful application of method to the interpretation of the spectrum ofcis-[CrF2(en)2]+chromophore (en = ethylenediamine) in aqueous solution demonstrates the utility of this approach.

ISSN:0038-7010    

DOI:10.1080/00387019708001629

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The photoluminescence spectra of Tb3+doped lanthanide oxysulfides (Y2O2S, La2O2S and Gd2O2S) powder phosphors are reported. These phosphors display bright fluorescent green under a UV source. The colour emission richness has been understood by computing the colour co-ordinates ([Xbar],[Ybar]). From their recorded photoluminescence spectra, the relative fluorescence intensity ratios have also been determined to examine the host material effects.

ISSN:0038-7010    

DOI:10.1080/00387019708001630

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Variation of the partition coefficient of cyclohexylacetate (CA) was studied by a differential absorption spectroscopic method as a function of ethanol and (CTAB) cetyltrimethylammoniumbromide concentrations. Approach used was based upon the pseudo-two phase model, including effect of ethanol concentrations on the critical micelle concentration (CMC) of CTAB. Ethanol enhanced micelle formation of CTAB at concentrations below 1% by volume, had a slight inhibitory effect at higher concentrations and totally inhibited at a concentration above 15% by volume.

ISSN:0038-7010    

DOI:10.1080/00387019708001631

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining ranitidine hydrochloride in tablets. 2-Choloroacetophenon was used as the internal standard and DMSO-d6served as the PMR solvent. The concentration of drug per unit dose was calculated from the integration values for the resonance signals of ranitidine hydrochloride at 4.32 δ ppm and int. st. at 5.19 δ ppm. The method using commercial products gave comparable results to those obtained by the methods of UV spectroscopy and USP XXIII.

ISSN:0038-7010    

DOI:10.1080/00387019708001632

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An optogalvanic method based on the shift of the continuous spectrum frequency distribution is proposed. The accuracy of the shift indication depends on the frequency distribution of the absorbing transitions in the optogalvanic detector spectrum. The absorption in Ne/Cu hollow cathode discharge lamp is analysed in order to investigate the behaviour of the spectrum emitted by a red AC EL panel.

ISSN:0038-7010    

DOI:10.1080/00387019708001633

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The selectively acylated trehalose type disaccharide2was prepared from the corresponding ditriflate derivative1viathe inversion of configuration at C-4,4′ positions. Cleavage of the transient protecting group (O-acetyl) from2furnished partially blocked disaccharides (3and4) capable of chain extension at position 4 or positions 4 and 4′, respectively. Acetal and ketal formation of the synthetic galacto-galacto trehalose (5) yielded compounds6and7, respectively. The regioseiective benzoylation of7gave8which has a free hydroxyl groups at positions2and 2′.

ISSN:0038-7010    

DOI:10.1080/00387019708001634

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Preliminary studies concerning the structural characterization of inclusional complexation have been carried out between barbiturate and β-cyclodextrin on silver surface by using infrared reflection absorption spectroscopy (IRRAS). The results not only provide convincing evidence for the complex formation but also reveal special structural features of the supramolecules oriented on Ag surface.

ISSN:0038-7010    

DOI:10.1080/00387019708001635

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Fluorescence excitation and dispersed fluorescence spectra of jet-cooled naphthalene and 2,6-, 2,7-dimethylnaphthalenes have been measured. The frequencies of optical active vibrations in the ground and first excited singlet states have been determined. The new technique for calculation of planar vibration frequencies of polycyclic benzenoid hydrocarbons in the excited electronic states has been developed. The vibration frequencies in the ground and first excited singlet states of these molecules were calculated using the developed technique and the Ohno's model. The interpretation of vibronic spectral lines based on the comparison of the calculated and experimental data was made. The calculation rms errors for the vibration frequencies in the ground electronic states of the investigated molecules do not exceed 20 cm−1and are approximately 1.5 times higher for excited states without additional adjustment of parameters for individual molecules.

ISSN:0038-7010    

DOI:10.1080/00387019708001636

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The literature data on the change of vHXfrequencies in hydrogen-bonded complexes of different structure are analysed. It is shown that the earlier found frequency dependencies can have a simple physical explanation. It consists in the fact that the XH-bond of any molecule, apart from its proton-donor and proton-acceptor properties, also has certain transmission abilities. It means that when hydrogen bonds are conjugated, to the proton-donor ability of any XH-group is always added a certain part (specific for this XH-group) of the proton-donor ability of the molecule, in relation to which this XH-group acts as a proton-acceptor. Similarly, the proton-acceptor property of XH-group is increased by a certain part (specific for this XH-group) of the proton-acceptor ability of the molecule, in relation to which this XH-group acts as the proton-donor. The dependence of the proton-donor (proton-acceptor) ability on the bend of the angle adjacent to the hydrogen bond is found.

ISSN:0038-7010    

DOI:10.1080/00387019708001637

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor