摘要:

Two Spanish palygorskites, one from Cáceres (Serradilla) and the other from Segovia (Sacramenia) are studied by means of infrared spectroscopy techniques, both in their natural state and after systematic treatment with hydrochloric acid. The first one is identified as aluminic and the second as magnesic. It is found that the magnesic palygorskite is more easily attacked by the acid.

ISSN:0038-7010    

DOI:10.1080/00387018908053926

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Several 2-bromo-4′-substituted acetophenomes were investigated by vibrational and electronic spectroscopies. The solvent effect on the bands assigned to μCOand μC-Brtogether with the comparison between the fundamental and overtone μCOfrequencies indicate acis/gaucherotational isomerism. The progressive.

ISSN:0038-7010    

DOI:10.1080/00387018908053927

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The uv spectra of three new highly active against anaerobic bacteria 5-nitroimidazoles are reported. These experimental results are interpreted using CNDO/S method (Complete Neglect of Differential Overlap for Spectroscopy). Calculations show that the observed transitions, except one, are π→π* type transitions.

ISSN:0038-7010    

DOI:10.1080/00387018908053928

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Vibrational spectra of di-2-pyridyl ketone and di-2-pyridyl ketone-18O have been recorded in the solid and molten state in the infrared (4000–100 cm−1) and the Raman (4000–50 cm−1). Polarized Raman spectra of the molten state have also been measured. The assignment of vibrational bands is performed using the group vibrational concept, isotipic shifts data and polarization features of the normal modes. The presence of symmetric and antisymmetric vibrations arising from the coupling of both pyridyl rings is found and discussed.

ISSN:0038-7010    

DOI:10.1080/00387018908053929

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Europium may be determined by electrothermal atomic absorption spectrometry with good sensitivity when using procoated furnaces. The maximum allowable ashing temperature is 1600 °C and the optimal atomization temperature is 2600 °C. Similar results were obtained using two different atomizers and detection systems. At the wavelength used for the determination of europium, the background continuum emitted by the furnace is very strong. Care should be taken to eliminate scattering species from the windows of the furnace housing.

ISSN:0038-7010    

DOI:10.1080/00387018908053930

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

N-(O-hydroxy benzylidene)-P-Z-phenylamine (Salicylidene anilines), their N-oxides and P-Y-(N-benzylidene)-P-Z-phenyl amine-N-oxides coordinate with lanthanide shift reagents. Salicylideneanilines coordinate both with the hydroxy oxygen and the nitrogen of the C=N, but the position of coordination is found to be closer to the oxygen. Salicyclidene-N-oxides coordinate via the oxygens of the N- O and the hydroxy group. Larger molar shift values were obtained for salicylidene-N-oxides compared to salicylidene anilines.

ISSN:0038-7010    

DOI:10.1080/00387018908053931

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The cyclopentylmethyl free radical has been generated in argon matrices by UV irradiation of the corresponding diacyl peroxide at T = 20K. The infrared spectrum of the radical reveals an out-of-plane deformation of the radical center at 563 cm−1characteristic of primary alkyl radicals.

ISSN:0038-7010    

DOI:10.1080/00387018908053932

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Two- and three-photon resonant ionization spectroscopy is used to explore the high-lying electronic states of octafluorocyclooctatetraene (OFCOT). CNDO/S calculations are reported as an aid in the assignment of the observed valence transitions. The spectra agree quite well with the predictions of the semi-empirical method, which has not been previously tested at such high energies. The ionization potential for this molecule is estimated and the effects of “through-space” and “through-bond” coupling on the energy levels are discussed. Comparison is made to the already reported spectroscopy of the hydrocarbon analog.

ISSN:0038-7010    

DOI:10.1080/00387018908053933

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A circular flame atomizer system using a quartz T flame adapator has been developed for the direct determination of mercury. A thermospray nebulizer was used as a sample introduction device to the atomizer. This design gave a sensitivity (1% absorption) of 0.20 ppm and detection limits of 10 ppb at 1.0 mL/min solvent flow at 253.7 nm. The absolute sensitivity was 25 ng and absolute detection limits was 1.5 ng.

ISSN:0038-7010    

DOI:10.1080/00387018908053934

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Thermospray nebulizer interfaced HPLC-Flame AAS was used to study the effect of heavy metals (Al, Cd, Cu, Hg and Zn) on the chlorophylls of duckweed. Flame AAS was used as a metal specific detector of HPLC. Study indicated that heavy metals promote the degradation of chlorophylls. No evidence of direct replacement of central magnesium with heavy metals was found.

ISSN:0038-7010    

DOI:10.1080/00387018908053935

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor