Fig. 1.

Pulse sequence for ¹HN-detected frequency selective REDOR spectroscopy. The 1H magnetization is transferred to ¹⁵N for indirect evolution and then transferred back to ¹H for detection. A REDOR period is added before detection to dephase the ¹H magnetization with nearby ¹³C atoms (more details in text). The phase cycles were as follows: ϕ1 = x,x,-x,-x; ϕ2 = x,x,x,x,-x,-x,-x,-x; ϕ3 = y,-y; ϕ4 = y,y,-x,-x; ϕ5 = y,y,x,x,x,x,y,y,-x,-x,y,y,y,y,-x,-x,-y,-y,-x,-x,-x,-x,-y,-y,x,x,y,y,y,y,x,x; ϕ6 = x,y,x,y,-x,-y,-x,-y; ϕ7 = x,-x,-y,y,x,-x,-y,y,-x,x,y,-y,-x,x,y,-y