NMR Facility

Department of Chemistry University of Oxford

The table below summarises pictorially the most common correlations interrogated by NMR and the experiment classes associated with these investigations.

Some further brief explanation of the techniques listed may be found on the NMR acronyms page.

Full explanations of these methods may be found in the excellent text book:

High-Resolution NMR techniques in Organic Chemistry  by TDW Claridge.

Correlation

Principal technique(s)

Comments

1H-1H COSY

Proton J-coupling typically over 2 or 3 bonds.

1H-1H TOCSY

Relayed proton J-couplings within a coupled spin system. Remote protons may be correlated provided there is a continuous coupling network in between them.

1H-X HSQC

1H-X HMQC

One-bond heteronuclear couplings with proton observation.

 

1H-X HMBC

Long-range (multiple-bond) heteronuclear couplings with proton observation. Typically over 2 or 3 bonds when X= 13C.

X-X COSY

X-X INADEQUATE

H-X-X-H ADEQUATE

COSY only used when X–spin natural abundance > 20 %. Sensitivity problems when X has low natural abundance; can be improved with proton detection methods.

 

1/2D NOESY

1/2D ROESY

 

Through-space correlations. ROESY applicable to “mid-sized” molecules with masses of ca. 1-2 kDa.

 

2D HOESY

 

Heteronuclear through-space correlations. Sensitivity limited by X-spin observation.

1D saturation or inversion transfer

2D EXSY

Interchange of spins at chemically distinct locations. Exchange must be slow on NMR timescale for separate resonances to be observed. Intermediate to fast exchange may require lineshape analysis for deconvolution.

Spin-echo or Stimulated-echo methods

2D DOSY

Measurement of molecular self-diffusion using pulsed field gradient technology. Used often in studies of molecular associations.

Relaxation editing

STD

Water-LOGSY

Exchange transferred NOEs

Chemical shift perturbation

The qualitative detection of ligand binding to a macromolecular receptor, most often a protein, and the quantitative determination of binding affinities.