Exclusive correlation spectroscopy
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Exclusive correlation spectroscopy (ECOSY) is a nmr experiment originally inroduced by Christian Griesinger, Richard Ernst and coworkers, for the accurate measurement of small J-couplings between nuclei.
The idea behind the experiment is to measure an unresolved coupling with the help of a larger coupling which is resolved in a dimension orthogonal to the small coupling. For ECOSY experiment three active nuclei are needed (SXI spin system). The pulse sequence must be able to transfer magnetization from I to S without changing the spin state of X, otherwise ECOSY pattern will vanish.
[edit] Theory
Multiple quantum filtering enable us to change the sign of cross-peaks of multipletes in 2D nmr spectra. Therefore one can use it to simplify nmr spectra. ECOSY is a Correlation spectroscopy, simplified by application of various multiple quantum filterings and subsequent combination of spectra.
[edit] References
- Griesinger, C.&Ernst, R. R. (1987). Frequency offset effects and their elimination in NMR rotating-frame cross-relaxation spectroscopy. J. magn. Reson. 75, 261-271.
- Griesinger, C., Sorensen, O.W. & Ernst, R.R. (1985). Two-dimensional correlation of connected NMR transitions. J. Am. chem. Soc. 107, 6394-6396.
- Griesinger, C., Sorensen, O.W. & Ernst, R.R.(1986). Correlation of connected transitions by twodimensional NMR-spectroscopy. J. chem. Phys. 85, 6837-6852.
