Tutorials. 3D. Delays

3D NMR. Delays

In most 3D experiments, J-couplings are used to transfer magnetization from one nucleus to another one. The corresponding delays have been preset in the standard pulse programs to the optimized values reported in the original literature. You might want to change a value, for example, due to fast T2 relaxation. This can only be done by modifying the value in the pulse program. We recommend you to start with the set values.

Delay Coupling Constant length (ms) experiment remarks

d3 1/(3*J_CH) 2.2 ms 3D HBHA(CO)NH

d4 1/(4*J_CH) 1.6-1.8 ms 3D HBHA(CO)NH

d21 1/(6*J_CH) 1.1 ms

d21 1/(2*J_NH) 5.5 ms 3D HNCO

d22 1/(4*J_CO-CA) 4.0 ms 3D HN(CO)CA 3D HN(CA)CO 3.6 ms (Two-bond) 4.4 ms (One-bond)

d23 1/(4*J_N-CO) 1/(4*J_N-CA) 12.0 ms 3D HNCO 3D HNCA

d24 d28 1/(4*J_CC) 3.6 ms 3D HN(CO)CACB

d26 1/(4*J_NH) 2.3 ms 3D HNCO

d21 T(N) 12.4 ms 3D CBCA(CO)NH 3D HBHA(CO)NH

d23 T(C) 12.0 ms 2T=24 ms smaller than 1/(4*J_CH)

Delay	Coupling Constant	length (ms)	experiment	remarks
d3	*1/(3J_CH)**	2.2 ms	3D HBHA(CO)NH
d4	*1/(4J_CH)**	1.6-1.8 ms	3D HBHA(CO)NH
d21	*1/(6J_CH)**	1.1 ms
d21	*1/(2J_NH)**	5.5 ms	3D HNCO
d22	*1/(4J_CO-CA)**	4.0 ms	3D HN(CO)CA 3D HN(CA)CO	3.6 ms (Two-bond) 4.4 ms (One-bond)
d23	*1/(4J_N-CO) 1/(4J_N-CA)*	12.0 ms	3D HNCO 3D HNCA
d24 d28	*1/(4J_CC)**	3.6 ms	3D HN(CO)CACB
d26	*1/(4J_NH)**	2.3 ms	3D HNCO
d21	T(N)	12.4 ms	3D CBCA(CO)NH 3D HBHA(CO)NH
d23	T(C)	12.0 ms		2T=24 ms smaller than 1/(4*J_CH)