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Heteronuclear correlation

Because of the sensitivity gain from the indirect detection experiments, either HMQC or HSQC is usually the method of choice for establishing correlations between protons and 13C (as well as other heteronuclei, such as, 5N or 31P). HET-COR, the heteronuclear analog of COSY, must be used when the available (somewhat older) instrument does not have good indirect detection capability, but use of HETCOR is declining. [Pg.353]


The HETCOR spectrum of a naturally occurring isoprenylcoumarin is shown in Fig. 5.41. The spectrum displays one-bond heteronuclear correlations of all protonated carbons. These correlations can easily be determined by drawing vertical and horizontal lines starting from each peak. For example, peak A represents the correlation between a proton resonating at 8 1.9 and the carbon at 8 18.0. Similarly, cross-peaks E and F show that the protons at 8 4.9 and 5.1 are coupled to the same carbon, which resonates at 8 114.4 i.e., these are the nonequivalent protons of an exomethylenic... [Pg.257]

The one-bond HETCOR spectrum and C-NMR data of podophyllo-toxin are shown. The one-bond heteronuclear shift correlations can readily be made from the HETCOR spectrum by locating the posidons of the cross-peaks and the corresponding 5h and 8c chemical shift values. The H-NMR chemical shifts are labeled on the structure. Assign the C-NMR resonances to the various protonated carbons based on the heteronuclear correlations in the HETCOR spectrum. [Pg.288]

The one-bond hetero-COSYspectrum of 7-hydroxyfrullanoIide exhibits interactions for all nine protonated carbons. The most downfield crosspeaks, K and L, represent one-bond heteronuclear correlations of the two vinylic exomethylenic protons resonating at 8 5.71 and 6.06 with the C-13 carbon (8 120.5). The C-6a proton, which resonates downtield at 8 4.97 due to the directly bonded oxygen atom, displays correlation with the carbon resonating at 8 80.9 (cross-peak D). Cross-peaks G and M represent h interactions of the C-1 methylene protons (8 1.33 and 1.31, respectively) with C-1 (8 38.1). Similarly, cross-peaks E and F display heteronuclear interactions of the C-8 methylenic protons (8 1.48 and 1.72) with C-8 (8 30.7), while cross-peak C couplings of C-3 methylene protons at 8 1.97 and 1.99 with C-3 (8 32.5). Couplings between the C-1 methylene protons and C-1 (8 38.1) can be inferred from cross-peak A, though in this case both the C-1 a and protons resonate very close to each other (i.e., 8 1.31 and 1.33). Cross-peak C is due to C-9 methylene, while cross-peak I represents the C-15 methyl. The heteronuclear interactions between the most upheld C-2 methy-... [Pg.322]

The most downfield cross-peaks, V-Y, are due to heteronuclear couplings of the aromadc or vinylic protons and carbons. For instance, cross-peak Y represents heteronuclear interaction between the C-1 vinylic proton (8 5.56) and a carbon resonating at 8 134.0 (C-1). The downfield cross-peaks, V and W, are due to the heteronuclear correlations of the ortho and meta protons (8 7.34 and 7.71) in the aromatic moiety with the carbons resonating at 8 128.3 and 126.9, respectively. The remaining cross-peak X is due to the one-bond correlation of the C-4 aromatic proton (8 7.42) with the C-4 carbon appearing at 8 131.4. The cross-peak U displays direct H/ C connectivity between the carbon at 8 77.9 (C-6) and C-6 methine proton (8 4.70). The crosspeak T is due to the one-bond heteronuclear correlation of carbon... [Pg.323]

The HMQC spectrum of podophyllotoxin shows heteronuclear crosspeaks for all 13 protonated carbons. Each cross-peak represents a one-bond correlation between the C nucleus and the attached proton. It also allows us to identify the pairs of geminally coupled protons, since both protons display cross-peaks with the same carbon. For instance, peaks A and B represent the one-bond correlations between protons at 8 4.10 and 4.50 with the carbon at 8 71.0 and thus represent a methylene group (C-15). Cross-peak D is due to the heteronuclear correlation between the C-4 proton at 8 4.70 and the carbon at 8 72.0, assignable to the oxygen-bearing benzylic C-4. Heteronuclear shift correlations between the aromatic protons and carbons are easily distinguishable as cross-peaks J-L, while I represents C/H interactions between the methylenedioxy protons (8 5.90) and the carbon at 8 101.5. The C-NMR and H-NMR chemical shift assignments based on the HMQC cross-peaks are summarized on the structure. [Pg.325]

The HMQC spectrum of vasicinone shows nine cross-peaks representing seven protonated carbons, since two of them (i.e., A and B, and C and D) represent two methylene groups. The C-4a and )8 methylene protons (8 2.70 and 2.20) show one-bond heteronuclear correlations with the carbon resonating at 8 29.4 (cross-peaks A and B), while the C-So and )3 methylene protons (8 4.21 and 4.05) exhibit cross-peaks... [Pg.326]

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. [Pg.415]

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... [Pg.45]

Another alternative for the interpretation of 1,1-ADEQUATE data is available by overlaying HSQC and 1,1-ADEQUATE spectra. By plotting the two spectra in different colours, as was done in Figure 4, the direct 1H/13C heteronuclear correlation response is visible and provides a guide for interpretation that is sometimes convenient. A further alternative would be to overlay 1,1-ADEQUATE and GHMBC spectra responses appearing in both are identified as 2/ch correlations and all remaining... [Pg.225]

The development and application of multidimensional solid state homo- and heteronuclear correlation (HETCOR) NMR techniques have lead to an increasingly important role in structure solution of zeolitic materials and have had many practical applications in the detailed structural characterization of completely siliceous zeolites[6,7] and AlPOs.[8-ll] However, HETCOR NMR is not readily applicable to aluminosilicates... [Pg.17]

Figure 3. 1H/29Si 2D heteronuclear correlation of LTA zeolite with molar ratio... [Pg.240]

The details of this analysis, which is a generalization of a previous formalism for n = 1 [236], are beyond the scope of this review. Overall, the efficiency of R-INEPT and HMQC experiments has been found to be comparable, at least in applications involving 31P and 27Al. A major advantage of R-INEPT is that it can be combined with MQMAS or STMAS into a simple 2D heteronuclear correlation experiment, MQ/ST-J-HETCOR (Sect. 7.3). [Pg.171]

Figure 3 illustrates the resolution of two oxygen sites connected with Brpnsted protons [119] in HY zeolite. The separation of these sites from other, non-proto-nated positions in the zeolite framework was possible by a two-dimensional 1H-170 HETCOR (heteronuclear correlation) NMR experiment which was acquired at... [Pg.198]

Information about the surface and interface structures in hexadecylamine-capped CdSe NC of 2 nm size has been obtained by a variety of 1H, 13C, 113Cd, and 77Se NMR techniques [342]. The 77Se CP-MAS-NMR spectrum showed five partially resolved peaks from surface or near-surface Se environments. It was possible to obtain 2D heteronuclear correlation (HETCOR) spectra between 1H and the other three nuclei despite the inherent sensitivity limitations (the 77Se- 3I-I HETCOR experiment required 504 h ). The latter experiment indicated that the methylene protons of the hexadecylamine chain interact with the surface Se atoms via a tilt of the chain toward the surface. The surface Se atoms were not seen to interact with thiophenol present, and it was suggested that thiophenol binds to a selenium vacancy at the surface. [Pg.293]


See other pages where Heteronuclear correlation is mentioned: [Pg.1460]    [Pg.1497]    [Pg.124]    [Pg.258]    [Pg.321]    [Pg.163]    [Pg.249]    [Pg.182]    [Pg.185]    [Pg.216]    [Pg.217]    [Pg.218]    [Pg.218]    [Pg.219]    [Pg.232]    [Pg.233]    [Pg.340]    [Pg.347]    [Pg.348]    [Pg.1081]    [Pg.17]    [Pg.237]    [Pg.237]    [Pg.239]    [Pg.239]    [Pg.239]    [Pg.82]    [Pg.119]    [Pg.157]    [Pg.158]    [Pg.175]    [Pg.178]    [Pg.230]    [Pg.163]    [Pg.401]   
See also in sourсe #XX -- [ Pg.180 ]




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Basic Heteronuclear Correlation Experiments

Comparison of the Available Inverse-Detected One-Bond Heteronuclear Correlation Experiments

Correlated spectroscopy Heteronuclear shift-correlation

Direct Heteronuclear Chemical-Shift Correlation Via Scalar Coupling

Direct heteronuclear chemical shift correlation

Gradient heteronuclear multiple quantum correlation

HMBC/GHMBC heteronuclear shift correlation

Heteronuclear 2-bond correlation

Heteronuclear 2D correlation

Heteronuclear Chemical Shift Correlation Methods

Heteronuclear Correlation Experiments II

Heteronuclear Correlation HMBC

Heteronuclear Correlation by Indirect Detection

Heteronuclear Multiple-Bond Correlation, Selective (HMBCS)

Heteronuclear Relayed Proton Correlated Spectroscopy (HERPECS)

Heteronuclear X/Y correlation spectroscopy

Heteronuclear chemical shift correlation

Heteronuclear chemical shift correlation (HETCOR

Heteronuclear chemical shift-correlation spectroscopy

Heteronuclear chemical shift-correlation spectroscopy HETCOR)

Heteronuclear correlated spectroscopy

Heteronuclear correlated spectroscopy HETCOR)

Heteronuclear correlation HETCOR)

Heteronuclear correlation decoupling

Heteronuclear correlation experiment

Heteronuclear correlation multiple quantum coherence

Heteronuclear correlation spectra

Heteronuclear correlation spectroscopy

Heteronuclear correlation spectroscopy HETCOR)

Heteronuclear correlation spectroscopy reactions

Heteronuclear correlation through multiple quantum

Heteronuclear correlation through multiple quantum coherence

Heteronuclear correlations characterization

Heteronuclear correlations technique

Heteronuclear dipolar correlation

Heteronuclear dipolar correlation techniques

Heteronuclear long-range shift correlation method

Heteronuclear multibond correlation

Heteronuclear multiple bond correlation HMBC)

Heteronuclear multiple bond correlation HMBC) spectroscopy

Heteronuclear multiple bond correlation chemical shifts

Heteronuclear multiple bond correlation compounds

Heteronuclear multiple bond correlation constant-time experiments

Heteronuclear multiple bond correlation correlations

Heteronuclear multiple bond correlation examples

Heteronuclear multiple bond correlation experiment

Heteronuclear multiple bond correlation experimental verification

Heteronuclear multiple bond correlation measurements

Heteronuclear multiple bond correlation method

Heteronuclear multiple bond correlation parameters

Heteronuclear multiple bond correlation principles

Heteronuclear multiple bond correlation pulse sequence

Heteronuclear multiple bond correlation spectra

Heteronuclear multiple bond correlation spectroscopy

Heteronuclear multiple quantum coherence-total correlation

Heteronuclear multiple quantum correlation

Heteronuclear multiple quantum correlation HMQC)

Heteronuclear multiple quantum correlation examples

Heteronuclear multiple quantum correlation pulse sequence

Heteronuclear multiple-bond correlation

Heteronuclear multiple-bond correlations proton detected

Heteronuclear multiple-quantum correlation combination experiments

Heteronuclear shift correlated spectra

Heteronuclear shift correlation experiments correlations

Heteronuclear shift-correlation

Heteronuclear shift-correlation determination

Heteronuclear shift-correlation long-range experiments

Heteronuclear shift-correlation principle

Heteronuclear shift-correlation pulse sequence

Heteronuclear shift-correlation spectroscopy

Heteronuclear single quantum coherence correlation experiment

Heteronuclear single quantum coherence-total correlated

Heteronuclear single quantum correlation

Heteronuclear single quantum correlation HSQC)

Heteronuclear single quantum correlation HSQC) spectra

Heteronuclear single quantum correlation examples

Heteronuclear single quantum correlation pulse sequence

Heteronuclear single quantum correlation spectroscopy

Heteronuclear single quantum multiple bond correlation

Heteronuclear single-bond correlation spectroscopy

Heteronuclear single-bond correlations

Heteronuclear single-bond correlations proton detected

Heteronuclear single-quantum correlation HSQC-TOCSY

Heteronuclear single-quantum correlation enhancements

II Heteronuclear shift correlation

Long-Range Heteronuclear Chemical Shift Correlation - HMBC

Long-range heteronuclear chemical shift correlation

New Long-Range Heteronuclear Shift Correlation Methods

Nuclear magnetic resonance heteronuclear correlation experiments

Sensitivity heteronuclear correlations

Shift correlation experiment, heteronuclear

Shift correlation experiment, heteronuclear chemical structure

Shift correlation heteronuclear couplings

Shift correlation, heteronuclear accordion-optimized

Shift correlation, heteronuclear direct

Shift correlation, heteronuclear heteronucleus-detected

Shift correlation, heteronuclear inverse-detected

Shift correlation, heteronuclear long-range

Shift correlation, heteronuclear proton-detected

Solid-state heteronuclear correlation

Solid-state heteronuclear correlation experiment

Solid-state heteronuclear multiple-quantum correlation experiment

Total correlated spectroscopy heteronuclear single quantum

Understanding the Heteronuclear Multiple-Bond Correlation (HMBC) Pulse Sequence

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