Bruker BioSpin Solid State NMR

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User Manual Version 002 BRUKER BIOSPIN 137 (327)

RFDR 10

Radio Frequency-Driven Recoupling (RFDR) with longitudinal magnetization ex-

change is a homonuclear dipolar recoupling experiment. This easy setup tech-

nique is a zero-quantum recoupling sequence that achieves chemical shift

correlation under MAS conditions. The time-dependence of the cross peak ampli

tudes can be employed to determine inter-nuclear distances. With short dipolar

recoupling times, only spins in close spatial proximity lead to cross peak facilitat

ing assignment of

C resonances in uniformly labelled peptides for instance.

RFDR may also be used in order to correlate chemical shifts and crystallographic

sites on materials samples.

The homonuclear dipolar recoupling is implemented via the application of rotor-

synchronised 180-degree pulses (one inversion pulse per rotor period). The phas

es of the 180-degree pulses are cycled with Gullion’s compensated XY-8 echo se-

quence in order to achieve efficient recovery of single spin magnetization and to

generate an effective dipolar recoupling Hamiltonian during the mixing period.

The critical experimental point is to avoid

H-X recoupling induced by interference

between the

H decoupling rf field and

C rf recoupling field. This effect can be

removed using a

H decoupling rf field 3 times as strong as the

C rf field used

for recoupling or by using Lee-Goldburg

H decoupling during the mixing period.

References:

1. T. Gullion, D. B. Baker and M. S. Conradi, New, compensated Carr-Purcell sequences, J. Magn.

Reson. 89, 479-484 (1990).

2. A. E. Bennett, J. H. Ok, R. G. Griffin and S. Vega, Chemical shift correlation spectroscopy in rotating

solids: Radio frequency-driven dipolar recoupling and longitudinal exchange, J. Chem. Phys. 96,

8624-8627 (1992).

3. A. E. Bennett, C. M. Rienstra, J. M. Griffith’s, W. Zhen, P. T. Lansbury and R. G. Griffin, Homonuclear

radio frequency-driven recoupling in rotating solids, J. Chem. Phys. 108, 9463-9479 (1998).

4. B. Heise, J. Leppert, O. Ohlenschläger, M. Görlach and R. Ramachandran, Chemical shift correlation

via RFDR: elimination of resonance offset effects, J. Biomol. NMR 24, 237-243 (2002).

Bruker BioSpin Solid State NMR - 10 Rfdr