Recoupling of chemical-shift anisotropy powder patterns in MAS NMR.
A comparison of three different implementations of the chemical-shift recoupling experiment of Tycko et al. [R. Tycko, G. Dabbagh, P.A. Mirau, Determination of chemical-shift-anisotropy lineshapes in a two-dimensional magic-angle-spinning NMR experiment, J. Magn. Reson. 85 (1989) 265-274] is presented. The methods seek to reduce the effects of artefacts resulting from pulse imperfections and residual C-H dipolar coupling in organic solids. An optimised and constant time implementation are shown to give well-defined and artefact free powder pattern lineshapes in the indirectly observed dimension for both sp2 and sp3 carbon sites. Experimental setup is no more demanding than for the original experiment, and can be implemented using standard commercial hardware.
Orr
Robin M
RM
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Duer
Melinda J
MJ
D016880:Anisotropy; D016477:Artifacts; D001554:Benzene / Q000737:chemistry; D002247:Carbon Isotopes; D005650:Fumarates / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000295:instrumentation / Q000379:methods*
D002247:Carbon Isotopes; D005650:Fumarates; C032005:fumaric acid; D001554:Benzene; D005998:Glycine