Dipolar double-quantum filtered rotational-echo double resonance.
The homonuclear dipolar coupling of a directly bonded (13)C-(13)C pair has been used to create a dipolar double-quantum filter (D-DQF) to remove the natural-abundance (13)C background in (13)C[(2)H] rotational-echo double-resonance (REDOR) experiments. The most efficient version of this experiment has the D-DQF excitation and reconversion preceding the REDOR evolution period. Calculated and observed (13)C[(2)H]D-DQF-REDOR dephasings were in agreement for a test sample of mixed recrystallized labeled alanines.