Measurement of internuclear distances in solid-state NMR by a background-filtered REDOR experiment
A background-filtered version of the rotational-echo double resonance (REDOR) experiment is demonstrated. The experiment combines a traditional REDOR pulse sequence with a double-cross-polarization (DCP) sequence to select only those signals coming from spin pairs of interest. The relatively inefficient DCP sequence, which transfers polarization from (1)H to (15)N and subsequently to (13)C, is improved by the use of adiabatic passages through the (-1) sideband of the Hartmann-Hahn matching condition. The result is an efficient 2D-REDOR pulse sequence that does not require a reference experiment for removal of background signals. The data produced by the experiment are ideally suited to analysis by newly developed dipolar transform methods, such as the REDOR transform. The relevant features of the experiment are demonstrated on simple labeled amino acids. Relative efficiencies of several other potential filtering methods are also compared. Copyright 2000 Academic Press.
Vogt
FG
Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, Pennsylvania, 16802-6300, USA.
Mattingly
SM
Gibson
JM
Mueller
KT