摘要:

A new method, involving the application of PMR spectroscopy for the assay of piperazine anhydrous, hydrate and its salts is described. The PMR spectrum of piperazine in D2o has a well-defined singlet system for the piperazine ring protons which is chosen for the quantitative measurement. The principal of the method involves comparing the integral of this signal to that of the sharp singlet (positioned at 0.00 ppm) of trimethyl silyl propane sulfonate sodium salt which is used as PMR reference and internal standard.

ISSN:0038-7010    

DOI:10.1080/00387018608069290

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An evaluation is made and some experiments are carried out which prove the possibility of optogalvanic effect appearing in experiments using hollow cathode discharge not only when one hollow cathode discharge is irradiated by another but also in the simplest possibly experimental scheme where only one hollow cathode discharge plays simultaneously the role of an emitter and an irradiator.

ISSN:0038-7010    

DOI:10.1080/00387018608069291

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

15N-Tribromoacetamide has been synthesized with an isotopic content of 99, 4%, its Raman spectra have been recorded in the range 4.000–50 cm−1. The isotopic shifts arising from15N have been determined and interpreted. We have assigned the vibrational spectra of Br3CCONH2and some overtones, combinations and difference bands. The molecular structure of tribromoacetamide has been studied employing the Ab Initio teoretical calculations and the Teller - Redlich isotopic product rule has been applied by assuming these geometrical parameters:

ISSN:0038-7010    

DOI:10.1080/00387018608069292

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The space-time distribution of the atoms of the elements A1, (T1), Mg, Ag, (Sn), (Si), Sb and Be in d.c. arc plasma during anode evaporation of samples containing a readily ionized additive, Li (as Li2CO3), was studied by spectral monochromatic equidensitometry. It was established that the distribution of the atoms in the interelectrode gap depends on the concentration of the readily ionized additive, the moment of burning of the arc and the physicochemical properties and ionization potential of the microadditive. The results obtained may be used to determine the optimum conditions for analysis of microelements in powdery samples.

ISSN:0038-7010    

DOI:10.1080/00387018608069293

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The photolysis of chloroform solutions containing 2-methyl-3-acetylquinoxalin N, N-dioxide (MAQO) and dialkyl amines leads to the observation of ESR spectra of the corresponding dialkyl nitroxides. Oxygen-transfer exciplex5which derived from the triplet state of MAQO is suggested as intermediate to give nitroxide through N-H bond cleavage in the secondary amine within5.

ISSN:0038-7010    

DOI:10.1080/00387018608069294

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Infrared and Raman spectra were obtained for 3,3,4-trimethylhexane and 2,2,5-trimethylhexane and were interpreted with the aid of normal coordinate calculations. It was shown that each compound exists as a mixture of two molecular conformations.

ISSN:0038-7010    

DOI:10.1080/00387018608069295

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Normal coordinate analyses have been carried out for D4hmodels of tetraphenylporphin molecule and its deuterated analogs. The assignment of resonance Raman active modes of tetraphenylporphin metal complexes and their deuterated derivatives is given.

ISSN:0038-7010    

DOI:10.1080/00387018608069296

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The molecular and electronic structure of the CuCl2-complexes with monoethanolamine (MEA) and triethanolamine (TEA), and their dynamical properties in solid and in DMF solutions were discussed on the basis of EPR measurements. Measurements indicate a dimeric structure of CuCl2-MEA complexes with very weak Cu-Cu coupling. Intradimer superexchange interaction is temperature dependent and decreases with temperature. In CuCl2-TEA monomeric complexes exist with a significant vibronic effect which is due to a change of dZ2 admixture to the d x2-y2ground state when temperature is changed.

ISSN:0038-7010    

DOI:10.1080/00387018608069297

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A sensitive method for the determination of trace amounts of mercury by complexation with 3-(2-Thiazolylazo)-2, 6-diaminopyridine (2, 6-TADAP) is described. Hg(II) forms a 1:2 complex with the reagent. Beer's law is obeyed over the range 5–40 μg in the total volume of 10 ml. The molar absorptivity was found to be 1.4 × 104L mol−1cm−1.This method is simple, rapid and involves no extraction steps whereby the use of gelatine as a solubilizing agent is described.

ISSN:0038-7010    

DOI:10.1080/00387018608069298

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The 60 MHz1H NMR spectra of racemic metaxalone,1, have been studied in CDC13solution at 28° with the achiral shift reagent tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato)europium(III),2, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)-d-cam-phorato]europium(III),3, and tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato]europium(III),4. Reagent3produced modest observable enantiomeric shift differences, ΔΔδ, for the CH20, aryl methyl, aryl H2,6 and the NH siqnals. Although reaquent 4 produced small or no observable ΔΔδ for the CH20, aryl methyls or aryl protons. strikingly qreater valuesof lanthanide induced shift, Δδ, as well as ΔΔδ, were found for the NH signal using 4 relative to 3. Analytical feasibility for direct optical purity determinations of 1 with 0 using this NH siqnal sclould allow detection of 74% of the minor enantiomer or less. Results are discussed ir terms of potential bidentate or tridentate chelation of 3 by 1 makinrl a greater contribution than for 4.

ISSN:0038-7010    

DOI:10.1080/00387018608069299

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor