Engineering NMR Selection Rules: Recoupling, decoupling and phase cycling,

A. Brinkmann, M. Carravetta, N. Ivchenko, X. Zhao, J. Schmedt auf der Günne, C. E. Hughes, P. K. Madhu, H. J. M. de Groot, J. Lugtenburg, W. de Grip, W. W. Bachovchin, and M. H. Levitt,
43rd Experimental NMR Conference, Asilomar, California, USA (Apr. 2002), talk.

Full text (PDF) (via Malcolm H. Levitt's homepage)

Nuclear spins interact more strongly with the experimental apparatus than with their molecular surroundings. As a result, spectroscopic selection rules may be engineered by controlling the electromagnetic fields, and mechanical manipulations, to which the sample is exposed.

One example is magic-angle-spinning solid-state NMR, where the symmetry of the pulse sequence may be used to control its recoupling and/or decoupling properties. We give applications to molecular structure determination in the solid state, including estimations of C–C bond lengths in the membrane protein rhodopsin, and studies of hydrogen bonding in histidine.

A second example of selection rule design is provided by phase cycling. We demonstrate a new design principle, called cogwheel phase cycling, which allows many NMR experiments to be performed in a shorter time. This is demonstrated for multiple-quantum MAS NMR of spins-3/2 in solids.

We also demonstrate another design principle, called multiplex phase cycling, which in some cases allows pure absorption 2D NMR spectra to be generated more quickly.

Dr. Andreas Brinkmann
National Research Council Canada
W. G. Schneider Building M-40
1200 Montreal Road
Ottawa, Ontario K1A 0R6
Tel. +1-613-990-0319
Fax. +1-613-990-1555