Two-dimensional correlation

I. Noda and Y. Ozaki, Two-Dimensional Correlation Spectroscopy, Wiley-Interscience, New York, NY (2004). 

Two-Dimensional correlation analysis to study Bronsted acid sites in zeolites... 

Keywords Two-Dimensional correlation, Infrared spectroscopy, Dealuminated H-Y zeolite, Bronsted acidity, MQ-MAS NMR. 

Hi) 2D-NMR (Two Dimensional Correlation Spectrocopy or Two Dimensional COSY Spectrum). 

D-NMR (TWO DIMENSIONAL CORRELATION SPECTROSCOPY OR TWO DIMENSIONAL COSY SPECTRUM)... 

The interaction between different hydrogens in a molecule, known as scaler or spin-spin coupling , transmitted invariably through chemical bonds, usually cover 2 or 3 at the most. Therefore, when a hydrogen with a chemical shift A is coupled to a hydrogen with chemical shift B , one would immediately make out that the hydrogens must be only 2 or 3 bonds away from one another. To know exactly with particular hydrogens are coupled to one another it is necessary to record a two-dimensional Correlation Spectroscopy (COSY) spectrum. 

Two-Dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY)... 

Over the last 10-15 years, multidimensional (3D and 4D) NMR spectroscopic and computational techniques have been developed to solve structures of larger proteins in solution. This technology has the advantage of resolving the severe overlap in 2D NMR spectra for proteins having >100 residues. Usually, multidimensional NMR experiments require isotopic labeling of some or all nuclei of interest. For example, signal overlap in a two-dimensional correlation spectrum can be resolved in the dimension of the heteronucleus—that is, N or attached to the protons of relevance. If fast relaxation is a problem,... 

Two-dimensional correlation experiments with detection of a heteronucleus... 

NMR spectroscopy was carried out using a Varian Unity 300MHz spectrometer. Peptides were dissolved in 500 pL of 90% H,O/10% D20 (or 100% D20) giving a sample concentration of 1-2 mM and the pH adjusted to 5.5. H DQF-COSY (double quantum filtered two-dimensional correlated spectroscopy), ROESY, and TOCSY spectra were collected at 25 °C and processed as described.1 6-281... 

Generalized two-dimensional correlation (2DCOS) analysis is based on a crosscorrelation analysis of spectra as a function of two independent wave number positions, thereby spreading the spectra over an additional dimension, and is a useful approach to studying structural changes in biological and chemical species. The 2D technique is applicable to any external perturbation, such as... 

Two-dimensional data analysis [160, 161] is a very powerful technique that examines correlated changes in spectra with changes in any other measurement of sample perturbation. The elegance of the method demonstrated in earlier studies has been extensively augmented by finer details on application and numerous examples. The primary advantage of two-dimensional correlation analysis lies in the extension of data examination space to a second domain. Subtle changes that may not be easily discernable in spectra and even weak spectral effects may be easily enhanced and understood in the context of molecular spectra [162]. 

Evidence in support at the H and 13C spectral assignments was obtained from two-dimensional correlation spectroscopy (COSY) experiments. Proton-proton (H-H COSY) results are shown in Fig. 8.9. 

Figure 5. Two-dimensional correlation spectrum between 29Si (vertical axis) and H (horizontal axis) sites forMCM-41 impregnated with [Pd Ru CO JpSIEt. ...

Noda, I., Generalizd two-dimensional correlation method applicable to infrared, Raman, and other types of spectroscopy, Applied Spectroscopy, 47,1329 (1993). 

Detailed assignment of the protons in the cyclopentadienylidene-2//-thiopyran (76, X = H) was accomplished by both two-dimensional correlation spectroscopy and nuclear Overhauser effect experiments. Selective deuteration at C-3 (X = D) simplified the couplings with H-4 appearing as a dd with7 = 6.8, 1.2Hz <1991TL3499>. 

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