3D HCN and HNC NOESY
From NMR Wiki
Spectra have no strong diagonal peaks due to orthogonal filtration on two heteronuclei. Spectra show NOE's between CH and NH protons. Together the two experiments provide pseudo-4D information while benefiting from better S/N ratio and resolution of 3D spectra.
Diercks, T., Coles, M., Kessler, H.. {An efficient strategy for assignment of cross-peaks in 3D heteronuclear NOESY experiments}
