Formation of Stable Radicals by Mechanochemistry and Their Application for Magic Angle Spinning Dynamic Nuclear Polarization Solid-State NMR Spectroscopy.

Autor: Carnahan SL; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States.; Iowa State University, Department of Chemistry, Ames, Iowa 50011, United States.; St. Mary's University of Minnesota, Department of Chemistry, Winona, Minnesota 55987, United States., Riemersma K; Iowa State University, Department of Chemistry, Ames, Iowa 50011, United States., Hlova IZ; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States., Dolotko O; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States., Kmiec SJ; Iowa State University, Department of Materials Science and Engineering, Ames, Iowa 50011, United States., Lamahewage SNS; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States.; Iowa State University, Department of Chemistry, Ames, Iowa 50011, United States., Martin SW; Iowa State University, Department of Materials Science and Engineering, Ames, Iowa 50011, United States., Wishart JF; Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States., Dubroca T; National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States., Balema VP; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States.; Clemson University, Materials Science & Engineering, Clemson, South Carolina, 29634, United States., Rossini AJ; U.S. Department of Energy, Ames National Laboratory, Ames, Iowa, 50011, United States.; Iowa State University, Department of Chemistry, Ames, Iowa 50011, United States.
Jazyk: angličtina
Zdroj: The journal of physical chemistry. A [J Phys Chem A] 2024 May 09; Vol. 128 (18), pp. 3635-3645. Date of Electronic Publication: 2024 Apr 25.
DOI: 10.1021/acs.jpca.4c00228
Abstrakt: High-field magic angle spinning (MAS) dynamic nuclear polarization (DNP) is becoming a common technique for improving the sensitivity of solid-state nuclear magnetic resonance (SSNMR) by the hyperpolarization of nuclear spins. Recently, we have shown that gamma irradiation is capable of creating long-lived free radicals that are amenable to MAS DNP in quartz and a variety of organic solids. Here, we demonstrate that ball milling is able to generate millimolar concentrations of stable radical species in diverse materials such as polystyrene, cellulose, borosilicate glass, and fused quartz. High-field electron paramagnetic resonance (EPR) was used to obtain further insight into the nature of the radicals formed in ball milled quartz and borosilicate glass. We further show that radicals generated in quartz by ball milling can be used for solid-effect DNP. We obtained 29 Si DNP enhancements of approximately 114 and 33 at 110 K and room temperature, respectively, from a sample of ball milled quartz.
Databáze: MEDLINE
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