Ultrabroadband 1D and 2D NMR Spectroscopy

The chemical shift range of many NMR-active isotopes cannot be excited in a single experiment by classical hard pulse high-resolution spectroscopy or even conventional broadband excitation. Such nuclei can be addressed by specifically optimized saturation pulses or xy-excitation, which are derived from linear frequency sweeps that are further optimized using methods derived from optimal control theory. A multi-isotope 1D experiment covering 6 MHz as well as homonuclear COSY and heteronuclear HMBC experiments covering more than 100 kHz are demonstrated, which can be adapted to fit any needs for specific isotopes at any spectrometer field. In general, the approach is very useful for 1D and 2D absolute value overview spectra at high magnetic fields and/or wideband and low-gamma nuclei.