July 14, 2022
Journal Article

Methyl-Driven Overhauser Dynamic Nuclear Polarization

Abstract

The Overhauser effect is unique among DNP mechanisms in that it requires the modulation of the electron-nuclear hyperfine interactions. While it dominates DNP in liquids and metals, where unpaired electrons are highly mobile, Overhauser DNP is possible in insulating solids if rapid structural modulations are linked to a modulation in hyperfine coupling. Herein, we report that Overhauser DNP can be triggered by the strategic addition of a methyl group, demonstrated here in a Blatter’s radical. The rotation of the methyl group leads to a modulation of the hyperfine coupling to its protons, which in turn facilitates electron-nuclear cross-relaxation. Removal of the methyl protons, through deuteration, quenches the process, as does the reduction of the hyperfine coupling strength. This result suggests the possibility for the design of tailor-made Overhauser DNP polarizing agents for high-field MAS-DNP.

Published: July 14, 2022

Citation

Perras F.A., D.F. Flesariu, S.A. Southern, C. Nicolaides, J.D. Bazak, N.M. Washton, and T. Trypiniotis, et al. 2022. Methyl-Driven Overhauser Dynamic Nuclear Polarization. The Journal of Physical Chemistry Letters 13, no. 18:4000-4006. PNNL-SA-172525. doi:10.1021/acs.jpclett.2c00748

Research topics