Proton Magnetic Resonance PMR Spectroscopy

Various workers have developed analyses for physical mixtures and block copolymers based on the ratio of the incremental methylene area to the total polymer proton 

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This chapter exclusively deals with nuclei of spin 1/2 and, therefore, the examples and applications shall be given from JH i.e., proton magnetic resonance (PMR) spectroscopy. 

The use of NH coupling in proton magnetic resonance PMR spectroscopy (Section V,G,2) and dipole moment measurements has enabled the greater stability of 275b over 275c362,363 and 276a over... 

T1he conformational studies (I) on acyclic sugar derivatives and on aldopentopyranose derivatives that have been conducted in our laboratories during the last few years are surveyed, and some of our more recent results in each of these areas are introduced. For each aspect the sugar derivatives were examined in solution by proton magnetic resonance (PMR) spectroscopy, and the data obtained were used to provide conformational information. Acyclic systems will be treated first. 

In 1971, one of us published a monograph which described the value of proton magnetic resonance (PMR) spectroscopy to medicinal chemists and to their biochemical colleagues [1]. Examples were drawn from results published over a period from the late 1950 s, when commercial NMR spectrometers first... 

Pmr. Proton magnetic resonance (pmr) spectroscopy provides a reliable analysis of pyrrolizidine alkaloids if sufficient quantities of alkaloid 1 mg) are present The amount of total alkaloid is estimated by comparison of the area of the vinyl proton (H2) signal (present in all 1,2-unsaturated and seco alkaloids) with that of an added internal standard ( dinitrobenzene)... 

Most of the hop resins contain -di- and p-tri-carbonyl functions which are enolized. It is seldom possible to isolate the individual tautomers but estimates of the relative proportions can be obtained by proton magnetic resonance (PMR) spectroscopy and other physical methods. Irrespective of the major component a tautomeric mixture can react in any form if, for example, a minor tautomer is consumed in a reaction it will be regenerated from the major tautomers, according to the equilibrium, until the reaction is complete. Thus phloroglucinol, the parent of the hop resin, exists almost entirely in the trienol form (17) but can react as cyclohexone-1,3,5 trione (18) to form a trioxime (19). 

Chemical fractionation methods used in this study were gel cFromatography, acid-base neutral solvent partitioning and chromatography on silica gel columns. Identification of compounds was done by gas chromatography/mass spectrometry (GC/MS). Proton nuclear magnetic resonance (PMR) spectroscopy was used to characterize fractions and subfractions which were not amenable to GC/MS analysis. 

Nuclear magnetic resonance (NMR) spectroscopy is based on the absorption of radiofrequency electromagnetic radiation (of the order of 100 MHz) by atomic nuclei [mainl> protons proton magnetic resonance (PMR), but also C, N, F, Na, Mg, etc.] in substances placed ir... 

ALKYL-METAL COMPOUNDS STUDIED BY PROTON MAGNETIC RESONANCE SPECTROSCOPY (PMR)... 

The hydrocarbon ("oil") fraction of a coal pyrolysis tar prepared by open column liquid chromatography (LC) was separated into 16 subfractions by a second LC procedure. Low voltage mass spectrometry (MS), infrared spectroscopy (IR), and proton (PMR) as well as carbon-13 nuclear magnetic resonance spectrometry (CMR) were performed on the first 13 subfractions. Computerized multivariate analysis procedures such as factor analysis followed by canonical correlation techniques were used to extract the overlapping information from the analytical data. Subsequent evaluation of the integrated analytical data revealed chemical information which could not have been obtained readily from the individual spectroscopic techniques. The approach described is generally applicable to multisource analytical data on pyrolysis oils and other complex mixtures. 

Pmr abbr. of Proton nmr. See Nuclear magnetic resonance spectroscopy. 

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