摘要:

Most of the previous relations1–3for the calculation of vibrational constant of diatomic molecules are electronegativity dependent. Electronegativity (X) is a complex quantity containing an atomic term depending on the charge and hybridization of the atom, and a molecular term depending on the length and the nature of the bonds in the molecule and as such it is not as precise as the bond length reor the reduced mass μ of the molecule. Thus the formule dependent on the electronegativity are expected to yield divergent results. Though there is a relation given by Varshni and Guggenheimer4which is free from electronegativity but the drawback is that it depends on too many quantities and also contains two empirical constants. Therefore it was thought to propose a new relation free from electronegativity, containing a single constant A, depending only on reand μ.

ISSN:0038-7010    

DOI:10.1080/00387017408067235

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The band frequencies and integrated intensities of the carbonyl stretching absorptions in a series of substituted benzophenones were examined as a function of the inductive and mesomeric effects of the substituents.

ISSN:0038-7010    

DOI:10.1080/00387017408067236

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The amide groups of poly(N-methyl laurolactam), poly(N-ethyl laurolactam) and poly(N-benzyl laurolactam) were shown by PMR and CMR to acquire both theantiandsynconformations in CDCl3at 30°C. At 80°C, the PMR signals of the two conformations collapsed to one signal, at an intermediate chemical shift. Theanti - synPMR and/or CMR signals were displayed by carbon nuclei and protons of all the groups which are directly bonded to the amide moieties in the three polymers. The magnetic non-equivalence of the carbon nuclei and protons of a number of other groups which are not directly linked to the amide functions was also demonstrated.

ISSN:0038-7010    

DOI:10.1080/00387017408067237

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

It is recognized that in α-diazoketones free rotation about the central C-C bond might be hindered through positive overlap of the carbonyl π-system with the p orbital on the α-carbon part of the CNN fragment.1,2

ISSN:0038-7010    

DOI:10.1080/00387017408067238

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Mean amplitudes of vibration were calculated from spectroscopic data for all the types of interatomic distances in AleCleand Fe2Cl6.

ISSN:0038-7010    

DOI:10.1080/00387017408067239

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Gas chromatographic - mass spectrometric techniques are gaining acceptance as a tool for drug identification. Standard techniques for the analysis of street drugs are still based upon infrared and ultraviolet spetra in conjunction with specific chemical test. These standard methods are adequate for the identification of a majority of confiscated drugs; but due to the increasing diversification of street drugs, these methods are becoming less conclusive.

ISSN:0038-7010    

DOI:10.1080/00387017408067240

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Recently the synthesis of 4,6,7-trichloro-δ5-3-keto steroids has been described and the conformation of ring A (“skew” boat) and the stereochemistry of hte three chloro substituents (4α-and 7α-chlorines axial) was established by the single crystal X-ray analysis of 4α,6,7α-trichloro-17α, 21-dihydroxypregn-5-ene-3, 11,20-trione 21-acetate III.1In order to correlate the solid state conformation with that in solution and also to demonstrate that the same conformation of ring A (and that of the 4-chloro substituents) is present when ring D is substituted differently, the ORD and CD spectra of II and 4α,6,7α-trichloro-5-androsten3-one acetate I,4α,6,7-α-trichloro-17α-hydroxypregn-5-ene-3, 20-dione acetate II and 4α,6,7α-trichloro-21-hydroxy-16-methylpregn-5, 16-diene-3, 11,20-trione acetate IV2have been recorded in dioxane. The experimental results of the four compounds are in agreement with the boat conformation of ring A and the axial position of the 4-Cl substituent. The pertinent data is summarized in Table 1 and demonstrated in Figures 1 and 2.

ISSN:0038-7010    

DOI:10.1080/00387017408067241

出版商:Taylor & Francis Group    

年代:1974

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:10.1080/00387017408067234

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor