Two-dimensional /-correlated spectroscopy

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

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)... 

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... 

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. 

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>. 

A structure can be deduced from a set of substructures. The latter is derived from multispectra. The structure elucidation involves extracting the set of substructures from multispectra and then assembling them. Let us consider two-dimensional Correlated SpectroscopY (COSY) as shown in Fig. 2. A cross-peak indicates that two protons in atoms have a spin coupling, which implies that they are separated by two or three bonds... 

At the qualitative level, NMR studies devoted to this issue exploit heteronuclear dipolar recoupling to correlate resolved MAS NMR signals of the nuclear species associated with different network formers. This information comes from the dephasing of the observe nuclei in REDOR, TRAPDOR, or REAPDOR experiments, or from one- or two-dimensional correlation spectroscopy involving coherence transfer via TEDOR (transferred echo double resonance) or... 

In complete analogy to NMR, FT EPR has been extended into two dimensions. Two-dimensional correlation spectroscopy (COSY) is essentially subject to the same restrictions regarding excitation bandwidth and detection deadtime as was described for one-dimensional FT EPR. In 2D-COSY EPR a second time dimension is added to the FID collection time by a preparatory pulse in front of the FID detection pulse and by variation of the evolution time between them (see figure B1.15.10(B)). The FID is recorded during the detection period of duration t, which begins with the second 7r/2-pulse. For each the FID is collected, then the phase of the first pulse is advanced by 90°, and a second set of FIDs is collected. The two sets of FIDs, whose amplitudes oscillate as functions of t, then undergo a two-dimensional complex Fourier transformation, generating a spectrum over the two frequency variables co and co,. 

In addition to Stock s experimental work, as well as Lipscomb s and Longuet-Hig-gins theoretical investigations, and pioneering X-ray structure studies by Lipscomb and others (mentioned, in part, above see also Lipscomb s book, 1963), B NMR spectroscopy was very helpful for structural elucidations. With the advent of two-dimensional correlation spectroscopy techniques (2D-COSY) (see Ernst et al., 1987 Ernst 1992), uncertainties in assignment of peaks have been considerably reduced, as shown by the work of Wade (1991) on derivatives of 1,2-carboranes (C2B10H12) and others (see review of Beaudet, 1988). Structural and electronic aspects of boranes and carboranes have been summarized by various authors in the book edited by Olah et al. (1991). 

Y. Wang, R. Tsenkova, M. Amari, F. Terada, T. Hayashi, A. Abe, Y. Ozaki Potential of Two-Dimensional Correlation Spectroscopy in Analysis of NIR Spectra of Biological Fluids. I. Two-Dimensional Correlation Analysis of Protein and Fat Concentration-Dependent Spectral Variations of Milk", Analusis Magazine, 1998 26, M64-M69... 

Figure 3.21 Two-dimensional correlation spectroscopy of a highly siliceous ZSM-12 zeolite enables all seven different sites to be resolved, and for the Si-O-Si site connectivity to be determined by looking for Si-Si cross peaks. [Reproduced from reference 112 with permission. Copyright 1990...

More recently, Noda has proposed the use of infrared two-dimensional correlation spectroscopy (2D-IR) to increase the information that can be extracted from a spectrum. This approach, essentially different from 2D-NMR spectroscopy, uses correlation analysis of the dynamic fluctuations caused by an external perturbation to enhance spectral resolution without assuming any line shape model for the bands. The technique was intended for the study of polymers and liquid crystals, and it has recently been applied to proteins. In the latter case, the perturbation can be achieved through changes in temperature, pH, ligand concentration and lipid-to-protein ratio. 

Noda, I., Dowrey, A.E., Marcott, C., Story, G.M. and Ozaki, Y. (2000). Generalized two-dimensional correlation spectroscopy. Appl. Spectrosc. 54 236a-248a. 

Macromotecular Symposia Vol.119, July 1997, p.1-13 APPLICATIONS OF TWO-DIMENSIONAL CORRELATION SPECTROSCOPY IN DEPTHPROFILING PHOTOACOUSTIC SPECTROSCOPY, NEAR-INFRARED DYNAMIC RHEO-OPTICS, AND SPECTROSCOPIC IMAGING MICROSCOPY Noda I Story G M Dowrey A E Reeder R C ... 

Noda, Frontiers of two-dimensional correlation spectroscopy. Part 2. Perturbation methods, fields of applications, and types of analytical probes. J. Mol. Struct. 1069 (2014) 23, http //dx.doi.Org/10.1016/j.molstruc.2014.01.016. 

I. Noda, Close-up view on the inner workings of two-dimensional correlation spectroscopy, Vib. Spectrosc. 60 (2012) 146. 

Two-dimensional correlation spectroscopy is used for detailed band assignment work. The technique allows spectral information to be analyzed that is much richer in information content than one-dimensional data. Cross-correlation analysis methods are applied to spectral combinations of NIR with NIR, or NIR and mid-infrared, allowing band assignments to be more easily accomplished. An excellent review paper describing the mathematics used in 2-D correlation spectroscopy along with several examples of generalized 2-D NIR and 2-D NIR-mid-infrared (MIR) heterospectral correlation analysis are introduced with 42 references by Ozaki and Wang. °... 

I. Noda, Recent Advancement in the Field of Two-Dimensional Correlation Spectroscopy , J. Mol. Struct., 2008, 883-884, 2. 

A modified COSY (two-dimensional correlated spectroscopy) revamped with an asymmetric Z-gradient echo detection (CRAZED) sequence was designed to obtain a better CEST contrast image based on the inter-molecular double quantum coherence method." Experiments were performed on an agar-glucose phantom, and the results demonstrate the feasibility of this method. 

R 2 M.H. Levitt, Spin Dynamics Basics of Nuclear Magnetic Resonance , John Wiley Sons, Inc., Chichester, UK, 2001 R 3 K.J.D. MacKenzie and M.E. Smith, Multinuclear Solid-State Nuclear Magnetic Resonance of Inorganic Materials in Pergamon Materials Series, Vol. 6, Pergamon, New York, N.Y., 2002 R 4 I. Noda and Y. Ozaki, Two-Dimensional Correlation Spectroscopy , Wiley, Chichester, UK, 2001... 

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