# Ultrabroadband 1D and 2D NMR Spectroscopy

## TL;DR

This paper introduces a new NMR technique using optimized pulses to cover large spectral ranges, enabling detailed analysis of multiple nuclei in one experiment.

## Contribution

The novel use of optimal control theory to design pulses for ultrabroadband NMR spectroscopy.

## Key findings

- A 1D experiment covering 6 MHz and 2D experiments covering over 100 kHz were successfully demonstrated.
- The method is adaptable to various isotopes and spectrometer fields, including high magnetic fields and low-gamma nuclei.
- Multinuclear NMR spectra are now possible with this approach.

## Abstract

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.

Optimal control‐derived saturation pulses allow 1D and 2D NMR spectroscopy covering spectral ranges in the MHz range. Next to a multitude of nuclei even multinuclear spectra are possible.