Easy DNP Enhanced Solid-State NMR: High Sample Temperatures and Low Microwave Powers

NMR (nuclear magnetic resonance) spectroscopy is limited by low sensitivity.

Recently, it has been shown that a technique called DNP (dynamic nuclear polarization) can enhance solid-state NMR signals by orders of magnitude.

DNP has enabled the determination of atomic-level structure in solids by accelerating complex multidimensional NMR experiments. However, only expert NMR spectroscopists apply DNP. This is because, DNP solid-state NMR requires highly specialized, large and expensive, dedicated equipment.

Currently, DNP experiments are performed with high power microwave sources (gyrotrons) and low sample temperatures near 100 K.

Gyrotrons and low-temperature control systems place a large demand on the building infrastructure and require expertise for routine operation.

Additionally, a low sample temperature reduces the resolution of NMR spectra dramatically, which hinders the characterization of chemical structure.This project aims to develop methods that will simplify the application of DNP and enable its widespread utilization.

We will develop methodology to perform DNP at high sample temperatures and low microwave powers, using compact microwave sources such as klystrons.

Specifically, we will focus on the development of polarizing agents designed for low power and sample formulations that are optimized for high temperatures.

Finally, we will perform liquid state Overhauser DNP at high temperatures and transfer the polarization to the surface of materials.

The proposed advances will eliminate the need for a gyrotron and low-temperature equipment and therefore, will simplify the DNP experimental setup.

This will enable the broad application of DNP to solve challenging problems in chemistry, materials science and biology that are inaccessible using conventional solid-state NMR.