摘要:

The use of “characteristic” N-O group frequencies, in characterising metal complexes with aromaticN-oxides is widespread. The most popular assignments of the N-O in-plane and out-of-plane bends ofN-oxides are shown to be in error, while the validity of transferring the N-O assignments of pyridineN-oxide to larger aromaticN-oxide systems is cautioned.

ISSN:0038-7010    

DOI:10.1080/00387019208018212

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

It is shown that processes of enrichment of low quality bauxite can be as effectively monitored by IR spectroscopy next to other generally applied analytical methods, such as chemicals analysis, X-ray diffraction and atomic absorption spectrophotometry. Changes were followed of characteristic vibration bands of main bauxite constituents, boehmite, haematite and kaolinite, as the carries of aluminum (gamma-AlOOH), iron (Fe2O3) and silicon [Al2SiO5(OH)4], respectively.

ISSN:0038-7010    

DOI:10.1080/00387019208018213

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Sensitive methods for the determination of trace amounts of cobalt and copper by complexation with 3-(2′-Thiazolylazo)-2,6- diaminopyridine (2,6-TADAP) are described. Copper forms a 1:2 violet complex with the reagent having a molar absorptivity of 1.00 × 104L mol−1cm−1, Baer's law is obeyed over the range 0 −50.84 μg in the total volume of 10ml. Cobalt also forms a 1:1 green complex with a molar absorptivity of 1.07 × 104L mol−1cm−1and obeying Beer's law over the range 0 –23.57 μg in the total volume of 10 ml. The procedure is simple and rapid without any tedious extraction steps for copper and without oxidation of cobalt (II) to cobalt (III).

ISSN:0038-7010    

DOI:10.1080/00387019208018214

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Spectral analyses of vinylneoxantho- and vinylisoneoxanthobilirubic acid methyl esters, withendoandexo-vinyl groups respectively, show that theexo-vinyl group causes (1) a greater bathochromic and hyperchromic shift of the long wavelength UV-vis absorption and (2) a smaller dimer association constant in CDCl3than does theendo-vinyl in these pyrromethenones.

ISSN:0038-7010    

DOI:10.1080/00387019208018215

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

o−, m−and p−aminobenzoic acid hydrazide (ABAH) complexes with (NH4)2Fe (So4)2and Fe Cl3were prepared with the type [ML2.2H2O] X. where X = Cl3or SO4. The prepared complexes were investigated using IR, electronic and Mossbauer spectroscopes. The obtained results indicated that the iron ions are present in octahedrally coordinated Fe2+, and Fe3+states.

ISSN:0038-7010    

DOI:10.1080/00387019208018216

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The mass spectra of 3,4-disubstituted-1,2,4-oxadiazole-5(4H)-thione and 3,4-disubstituted-1,2,4-thiadiazole-5(4H)-ones have been studied. The rearrangement of molecular ion of 1,2,4-oxadiazole-5-thiones to 1,2,4-thiadiazole-5-ones was proposed. Some major fragments observed in the spectra were interpreted and the fragmentation patterns involving McLafferty rearrangements were reported.

ISSN:0038-7010    

DOI:10.1080/00387019208018217

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

By the application of the spectrophotometric methods the composition of the complex and by the pH-metric method the reaction of complex formation in 70% ethanol, were determined. It was found that a complex WO3(C15H9O3)22-whose concentration stability constant β2ranged from 16.45 at pH 4.0 to 11.47 at pH 7.0, was formed. Conditions were investigated for the spectrophotometric determination of 3-hydroxyflavone by means of the reaction of complex formation. It was established that in 50% ethanol 3-hydroxyflavone can be determined with great accuracy in quantities from 0.05 to 0.30 mg/ml. All investigations were carried out at room temperature (20°C) and constant values of pH and ionic strength.

ISSN:0038-7010    

DOI:10.1080/00387019208018218

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A technique for determination of enantiomeric excess of cathinone, 2-amino-1-phenyl-1-propanone, by use of the chiral lanthanide shift reagent (LSR), tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato]europium (III), Eu (HFC)3, is described. The hydrochloride salt of the cathinone sample is first converted directly to theN-acetyl derivative without need for isolation of the potentially unstable cathinone free base. Addition of Eu (HFC)3to the crude acetylated cathinone resulted in near-baseline resolution of theCH3CO resonances of the enantiomers. Analytical utility and the sense of magnetic nonequivalence of this signal were demonstrated using “spiked” non-racemic samples.

ISSN:0038-7010    

DOI:10.1080/00387019208018219

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Fourier Transform Infrared Spectroscopy and Thermal Analysis have been used to study the thermal and termooxidative degradation of polysiloxane coatings obtained by treating E-glass fiber with aqueous solutions of 3-chloropropyltriethoxysilane. Initial weight losses were due to polymerization of the coatings. Severe oxidative degradations were observed at temperatures above 180°C. At 550°C the residue of the coating was found to be silica with free silanol groups.

ISSN:0038-7010    

DOI:10.1080/00387019208018220

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The infrared spectra of palladium(II) acetate crystals obtained from a benzene-acetic acid solution show that hexa-μ-acetato-triangulo-tripalladium(II)-water (2/1) i.e. the hemihydrate of hexa-μ-acetato-triangulo-tripalladium(II) was obtained. An empirical assignment of the observed bands is proposed.

ISSN:0038-7010    

DOI:10.1080/00387019208018221

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor