摘要:

This paper deals with the conformational analysis of some I,2-0-isopropylidene-α-D-glucofuranose derivatives2, viz. 3-0-toluene-psulphonyl-5,6-di-0-acetyl-(I), 3-0-toluene-psulphonyl-5-0-acetyl-6chloro-6-deoxy-(2), 3,5,6-tri-0-acetyl-(3), 3,5-di-0-acetyl-6-deoxy-(4), 3-0(N-phenyl) carbamoyl-5,6-di-0-acetyl-(5), 3-0-(N-phenyl) carbamoyl-5-0-acetyl-6-chloro-6-deoxy-(6), 3-0-(N-phenyl) carbamoyl-6-0-acetyl-(7) and 6-0)-acetyl, 3,5-0-phenyl boronate (8), that are of considerable interest from the point of view of their synthetic utilizations as well as the possibility of estabilshing relationship between PMR paramenters, conformation and reactivity of the mentioned class of compounds. Table I shows PMR parameters for compoundsI-8which we have studied, for protons at C-6 adn C-5, which were obtained by means of NMR spectrum computation program (the program was developed by one of us A.S.Fridman), and the values of corresponding dihedral and projected angles. Table 2 furnishes PMR data on compoundsI-8for the protons at C-I, C-3 and C-4 found from among appropriate soctra of the first order3.

ISSN:0038-7010    

DOI:10.1080/00387017408067212

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A number of rare earth chelates show bright line emissions. These emissions usually result from the absorption of energy in the broad absorption band of the chelating agent followed by transfer of this energy to an excited state of the central rare earth metal ion. This transfer is followed by emission from one or more of these excited states. The emission spectrum is characteristic of the rare earth ion -discrete, narrow lines - showing no band characteristic of the chelating agent. To understand the absorption, transfer, and emission of light energy in these materials, the efficiency of energy transfer and the quenching processes involved must be determined. A knowledge of the fluorescence quantum efficiency is essential.

ISSN:0038-7010    

DOI:10.1080/00387017408067213

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

One of us had previously reported an instrument that produces plused laser beams with multiple colors.1A pulsed nitrogen laser was focused on a 1 cm fluorometer cell mounted on a circular rotating table. As the table was rotated by a motor, the nitrogen laser was triggered synchronously as another cell moved into the focal point, and the dye laser output was obtained as a spacially superimposed beam. By filling the cells with various laser dye solutions, it was possible to tune to a number of wavelengths.

ISSN:0038-7010    

DOI:10.1080/00387017408067214

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

In this first paper in a series aimed at studies of chemistry in lasers, the molecular states in a dye laser are compared to those in the same solution under ordinary fluorescence conditions. Significant differences are found to exist which are readily apparent in case of molecules whose normal fluorescence is characterized by a sizeable Stokes O-O loss. Such differences are traced to the invalidity of the Born-Oppenheimer separation approximation for these molecules when the excited state lifetimes are greatly altered as in dyes lasers at high photon density. Representation of this particular type of Stokes shift requires an extension of the usual model based on only two hypersurfaces, namely, a time-ordered sequence of quantum states.

ISSN:0038-7010    

DOI:10.1080/00387017408067215

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The relative importance of the time-ordered sequence of precursor states is examined; their contribution to the ensemble is negligible for spontaneous emission, but under stimulated emission conditions at high photon density the dominant terms in the sequence, determining the ensemble properties, are different from the Franck-Condon relaxed state. The ‘chirp’ of a traveling wave laser is shown to be related to time-resolved spectroscopic measurements.

ISSN:0038-7010    

DOI:10.1080/00387017408067216

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Self scanning linear arrays of silicon photodiodes have been utilized as multichannel detectors in a variety of spectrochemical measurements (1,2,3,4). These arrays have densities of 1000 photodiodes per inch and can be thought of as completely solid state single line image sensors. In some earlier work (3) a spectrometer based on this detector was utilized for qualitative dc arc spectrochemical analysis. In this note we report on the utilization of an improved computer coupled photodiode array spectrometer system for simultaneous multielement quantitative analysis with a dc arc source.

ISSN:0038-7010    

DOI:10.1080/00387017408067217

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:10.1080/00387017408067211

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor