Total correlation spectroscopy homonuclear Hartmann-Hahn

Homonuclear Hartmann-Hahn Spectroscopy or Total Correlation Spectroscopy 267... 

HOMONUCLEAR HARTMANN-HAHN SPECTROSCOPY (HOHAHA), OR TOTAL CORRELATION SPECTROSCOPY (TOCSY)... 

We now want to turn to another experiment which, we must make clear at the start, does not have any relationship in theory to NOE experiments. In fact the theory is so complicated that we shall not say anything about it at all, but just refer you to one of the books in the Appendix. We are including this experiment because of its unique advantages when the spectrum has overlapping multiplets. It is called TOCSY, which stands for Total Correlation SpectroscopY (it has a second, more amusing name HOHAHA, standing for HOmonuclear HArtmann-HAhn), and is of particular use when oligosaccharides or peptides are under study. 

Various authors have used different names for Hartmann-Hahn-type experiments that emphasize distinct experimental or theoretical aspects. For example, heteronuclear Hartmann-Hahn transfer in liquids has been called coherence transfer in the rotating frame (Muller and Ernst, 1979), J cross-polarization (JCP Chingas et al., 1981), heteronuclear crosspolarization (Ernst et al., 1991), HEHAHA (heteronuclear Hartmann-Hahn transfer Morris and Gibbs, 1991), and hetero TOCSY (total correlation spectroscopy Brown and Sanctuary, 1991). Homonuclear Hartmann-Hahn transfer has been referred to as TOCSY (Braunschweiler... 

Heteronuclear Hartmann-Hahn sequences also effect homonuclear Hartmann-Hahn transfer, resulting in (heteronuclear and homonuclear) total correlation spectroscopy (TOCSY Bearden and Brown, 1989 Zuiderweg, 1990 Brown and Sanctuary, 1991 Ernst et al., 1991). Simultaneous heteronuclear and homonuclear magnetization transfer can be beneficial in relayed transfer experiments (Gibbs and Morris, 1992 Tokles et al., 1992 Majumdar et al., 1993). However, as pointed out by Ernst et al. 

Total correlation spectroscopy (TOCSY) also known as homonuclear Hartmann-Hahn (HOHAHA) experiment provides all relayed connectivities within a spin system [453, 454). The primary intention in TOCSY as in other relayed experiments is to establish connectivities in less crowded spectral regions to facilitate the assignment of spin systems. 

The most commonly used 2D nmr technique applied to through-bond interactions is termed (7 ) correlated spectroscopy (COSY), others are total correlation spectroscopy (TOCSY), which allows somewhat longer-range through-bond connectivities to be observed than with COSY, spin echo coherence transfer spectroscopy (SECSY), relayed coherence transfer spectroscopy (RELAY), double quantum spectroscopy (DQNMR) and homonuclear Hartmann-Hahn spectroscopy (HOHAHA). The most commonly used 2D nmr technique applied to through-space interactions is termed nuclear Overhauser effect spectroscopy (NOESY) also used is the closely related rotating-frame NOESY (ROE-SY). 

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