Solid-state nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical approaches for characterising molecular-level structure and dynamics. It is used by researchers in the physical and life sciences to address complex problems in systems as diverse as pharmaceuticals, battery materials, catalysis and protein complexes. Moreover, the power of solid-state NMR as an analytical technique is continually increasing in line with advances in NMR magnet technology. High magnetic fields maximise both the sensitivity and resolution of NMR spectra, meaning that more information can be obtained. In particular, the recent availability of spectrometers with magnetic fields of 23.5 T (a 1H NMR frequency of 1.0 GHz) represents a huge opportunity to study materials and biological systems in greater detail than ever before.
The importance of high-field NMR spectroscopy has been recognised by the UKRI's recent £20M investment in a UK-wide network of high magnetic field NMR facilities in 2018. This included a £8M 1.0 GHz spectrometer with the highest field in the UK for performing solid-state NMR measurements. Here, we propose to maximise the accessibility and impact of this world-leading spectrometer by combining it with the existing UK 850 MHz Solid-State NMR Facility to create a new UK High-Field Solid-State NMR National Research Facility. A range of magic angle spinning probes will be provided, from fast spinning (up to 111 kHz) facilitating proton-detected 13C and 15N experiments for the analysis of pharmaceuticals and protein complexes, to slower spinning larger volume systems that benefit the analysis of low-abundance and quadrupolar nuclei including 25Mg, 45Sc and 71Ga widely studied in materials science. In each instance, the sensitivity and resolution obtained from these samples is enhanced through their analysis at high magnetic fields.
The availability of two state-of-the-art solid-state NMR spectrometers, both with the potential to drive new developments in the field, together with a suite of specialist and custom-made NMR probes, within a single National Research Facility will allow both increased capacity and capability for UK NMR research. The combination of the 1.0 GHz spectrometer with ultrafast magic-angle spinning probes will enable experiments to be performed at the highest possible resolution and sensitivity, something which is critical for observing and correlating nuclei such as 1H, 13C and 15N in systems such as pharmaceuticals, protein complexes and plant cells. The high magnetic field is also particularly important for studying quadrupolar nuclei, which make up over one third of the periodic table and are of great importance in both materials and biological science, but suffer from additional broadening interactions that complicate their observation at low magnetic fields. At the same time, the 850 MHz spectrometer has a larger bore size so it can accommodate more specialist NMR probes e.g., high-temperatures up to 1000 K. This example is especially important for studying e.g., ion dynamics in battery and fuel cell materials or in situ reaction and crystallisation processes, where the ability to heat the sample over a wide temperature range is paramount. In addition, the 850 MHz spectrometer can accommodate more exotic NMR probe designs such as double-rotation probes for acquiring high-resolution spectra of quadrupolar nuclei.
The sustainable operation of the new Facility will based on the key factors that have enabled the success of the existing 850 MHz Facility: dedicated Facility Manager support and genuine nationwide buy-in achieved through the Facility Executive and an independent time allocation procedure. In addition, the Facility will actively engage with the UK NMR community through close interaction with the recently-established Connect NMR UK network, continuing to grow and diversify its user base beyond the NMR community through a range of outreach and engagement activities.