Heteronuclear correlation spectroscopy HETCOR

Heteronuclear correlation spectroscopy (HETCOR) Shift-correlation spectroscopy in which the chemical shifts of different types of nuclei (e.g., H and C) are correlated through their mutual spin-coupling effects. These correlations may be over one bond or over several bonds. 

In order to remove unwanted organic peaks in the proton spectra, one has to resort to 2D H- P heteronuclear correlation spectroscopy (HETCOR). When performed via CP, HETCOR sees only protons capable of pro-... 

Heteronuclear correlation spectroscopy (HETCOR or C-H HETCOR) (Section 9.12) A two-dimensional NMR method used to display the coupling between hydrogens and the carbons to which they are attached. 

Connectivity is disclosed even more powerfully by heteronuclear correlation spectroscopy (HETCOR). Here, an H NMR spectrum is juxtaposed with a C spectrum. This allows the mapping of a molecule along its entire C-H framework by revealing the identity of C-H bonded fragments. The principle is illustrated again with l-bromopropane in the spectrum shown below. 

The hydroformylation of an unsaturated steroid proceeded in high chemo-, diastereo-, and regioselectivity (Scheme 14.9) with diastereoselectivity assigned by correlation spectroscopy (COSY), and heteronuclear correlation spectroscopy (HETCOR) spectra." This reaction of this trisubstituted alkene used a [Rh(nbd)Cl]2 precursor (nbd) and P( -Bu)3 as a ligand, at 120°C and pressures of 100-120 bar. 

For compounds that contain a limited number of fluorine atoms, heteronuclear correlation spectroscopy experiments such as F H HETCOR and 2H-19F heteronuclear Overhauser enhancement spectroscopy (HOESY) can provide considerable assistance distinguishing structural isomers and diastereomers as well as for conformational analysis. HOESY experiments have been frequently used for conformational analysis of biomolecules containing fluorine labels.18... 

The number of sugar residues and constituent monosaccharides are determined by a combination of COSY (two-dimensional homonuclear correlation spectroscopy), HOHAHA (2D homonuclear Hartman-Hann spectroscopy) and HETCOR (direct heteronuclear correlation spectroscopy)... 

We present a solid-state nuclear magnetic resonance (NMR) experiment that allows the observation of a high-resolution two-dimensional heteronuclear correlation (2D HETCOR) spectrum between aluminum and phosphorous in aluminophosphate molecular sieve VPI-5. The experiment uses multiple quantum magic angle spinning (MQMAS) spectroscopy to remove the second order quadrupolar broadening in Al nuclei. The magnetization is then transferred to spin-1/2 nuclei of P via cross polarization (CP) to produce for the first time isotropic resolution in both dimensions. 

Of the many types of two-dimensional experiments, two find the most frequent application. One of these is H—H Correlation Spectroscopy, better known by its acronym, COSY. In a COSY experiment, the chemical shift range of the proton spectrum is plotted on both axes. The second important technique is Heteronuclear Correlation Spectroscopy, better known as the HETCOR technique. In a HETCOR experiment, the chemical shift range of the proton spectrum is plotted on one axis, while the chemical shift range of the C spectrum for the same sample is plotted on the second axis. 

It is also possible through selective heteronuclear singlefrequency decoupling to correlate bonded carbons and protons (HETCOR, Heteronuclear Correlated Spectroscopy) as an alternative to identify all directly bonded and longdistance carbon-proton pairs in a molecule. 

HETeronuclear CORrelation spectroscopy), can definitively prove molecular association between the different components in a salt or co-crystal. The ability of CP-HETCOR NMR spectroscopy to confirm co-crystal formation was recently demonstrated for a palmitic acid nicotinamide 1 1 co-crystal." ... 

Heteronuclear chemical shift-correlated spectroscopy, commonly called H-X COSY or HETCOR has, as the name implies, different and F frequencies. The experiment uses polarization transfer from the nuclei to the C or X nuclei which increases the SNR. Additionally, the repetition rate can be set to 1—3 of the rather than the longer C. Using the standard C COSY, the ampHtude of the C signals are modulated by the... 

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