摘要:

Secondary deuterium isotope effects have been observed for nitrogen- and oxygen- containing donors in the presence of lanthanide NMR shift reagents1–3. In each case the shifts observed in the NMR spectrum of the partially deuterated compound were larger than those for the non-deuterated analog. It is generally postulated that the greater inductive effect of deuterium compared to hydrogen causes the deuterated analog to compete more effectively for coordination sites on the lanthanide chelate4; however, steric effects cannot be eliminated as a possible explanation for this behavior. Secondary deuterium isotope effects have also been shown to effect the stability of complexes between silver(I) and olefins5. Once again the complex stability imcreases as the degree of deuterium substitution imcrease. Gas chromatographic stationary phases containing Ag(I) have been used to separate deuterated compounds from their less deuterated analogs6–9. In all cases the deuterated compound exhibited a longer retention time. In this paper the first obvservation of a secondary deuterium isotope effect in the presence of binuclear lanthanide (III) silver(I) NMR shift reagents10is reported.

ISSN:0038-7010    

DOI:10.1080/00387018408068047

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Infrared and Raman spectra were measured and analyzed for α-VSO5, α-VPO5and α-VMoO5. Band assignments were made for these phases using normal coordinate analysis. Trends in related force constants from their modified valence force fields were interpreted on the basis of differences in their chemical parameters. Empirical band assignments were made for β-VSO5on the basis of those for α-VSO5.

ISSN:0038-7010    

DOI:10.1080/00387018408068048

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Detailed studies on the infrared spectra of organic molecules are particularly useful since they often contribute significantly to a better knowledge of the molecular parameters. Owing to our particular interest in this field, a systematic investigation concerning the vibrational behaviour of different classes of organic compounds has been carried out in the last years (1–3).

ISSN:0038-7010    

DOI:10.1080/00387018408068049

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Complete sets of symmetry coordinates of molecular vibrations are developed for the distorted icosahedral models of (i)D5dand (ii)Thsymmetries, and (iii) the regular icosahedron; symmetryIh. The G matrix is given in the latter case (iii). Model calculations of vibrational frequencies are reported.

ISSN:0038-7010    

DOI:10.1080/00387018408068050

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The variation method applied to linear combinations is formulated in terms of matrix notation. Analogies with the matrices G and F of molecular vibrations are pointed out. The analogy is used to derive variational properties of the vibrational frequencies. The two-dimensional case is treated in particular and illustrated numerically by the totally symmetrical vibrations of PC13.

ISSN:0038-7010    

DOI:10.1080/00387018408068051

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In recent years there has been considerable interest in the spectroscopic properties of chlorophyll molecules. Among the techniques employed is resonance Raman spectroscopy which can provide vibrational spectra with high selectivity, from chlorophyllapresent in intact chloroplasts or cells.1However, detecting resonance Raman scattering from chlorophyllais hindered when excitation in the red region is used, owing to the strong fluorescence of the molecule near 670 nm. Copper pheophytinate, on the other hand, is largely non-fluorescent and thus lends itself to resonance Raman study in the red region. (The mechanism for fluorescence quenching in copper pheophytinate is believed to involve charge transfer from the porpnyrin ring to the Cu2+ion upon excitation, although direct experimental evidence is still lacking.) we felt that it would be of interest to carry out a resonance Raman study to copper pheophytinate in the red region and compare the results with what is already known about the resonance raman sperctrum of chlorophy 11a. An advantage of exciting in the red region is that athe QXand Qybamus in the red region are better resolved than the BXand Bybands in the blue region,2thus making it easier to observe different vibronic coupling in the red.

ISSN:0038-7010    

DOI:10.1080/00387018408068052

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A pneumatic crossflow nebulizer, modification of the Valente-Schrenk design, is used. The aerosol dehydration system consist of a specially designed spray chamber, in which a stationary temperature gradient is maintained, and a conventional helix condenser. The dependences of the uptake rate on the gas pressure and the gas flow are investigated, as well as the axial temperature distribution in the chamber. The nebulizer remains at 80°C and operates normally even with low dilutions of blood serum, whereas in the upper chamber part the temperature is 175°C.

ISSN:0038-7010    

DOI:10.1080/00387018408068053

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0038-7010    

DOI:10.1080/00387018408068046

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor