Distortionless enhancement of polarization

Major advances m NMR have been made by using a second rf transmitter to irra diate the sample at some point during the sequence There are several such techniques of which we 11 describe just one called distortionless enhancement of polarization transfer, abbreviated as DEPT... 

DEPT (Section 13.18) Abbreviation for distortionless enhancement of polarization transfer. DEPT is an NMR technique that reveals the number of hydrogens directly attached to a carbon responsible for a particular signal. 

Figure 13.6 is the proton-decoupled carbon-13 NMR distortionless enhancement of polarization transfer (DEPT) spectra of poly(methyl-l-pentene) [29]. This experiment, after data manipulation, separates the methine, methylene, and... 

The complete PMR and C assignments for a series of differently substituted thiadiazin-2//-thiones 30-32, having different groups on the two heterocyclic nitrogen atoms, have been presented <2001MRC222>. To assign all of the NMR signals unequivocally, 1-D and 2-D techniques such as distortionless enhancement of polarization transfer (DEPT 135), heteronuclear multiple quantum correlation (HMQC), and heteronuclear multiple bond... 

Nuclear Magnetic Resonance Spectroscopy. Like IR spectroscopy, NMR spectroscopy requires little sample preparation, and provides extremely detailed information on the composition of many resins. The only limitation is that the sample must be soluble in a deuterated solvent (e.g., deuterated chloroform, tetrahydro-furan, dimethylformamide). Commercial pulse Fourier transform NMR spectrometers with superconducting magnets (field strength 4-14 Tesla) allow routine measurement of high-resolution H- and C-NMR spectra. Two-dimensional NMR techniques and other multipulse techniques (e.g., distortionless enhancement of polarization transfer, DEPT) can also be used [10.16]. These methods are employed to analyze complicated structures. C-NMR spectroscopy is particularly suitable for the qualitative analysis of individual resins in binders, quantiative evaluations are more readily obtained by H-NMR spectroscopy. Comprehensive information on NMR measurements and the assignment of the resonance lines are given in the literature, e.g., for branched polyesters [10.17], alkyd resins [10.18], polyacrylates [10.19], polyurethane elastomers [10.20], fatty acids [10.21], cycloaliphatic diisocyanates [10.22], and epoxy resins [10.23]. 

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