Saturday, April 2, 2011

High-Field Dynamic Nuclear Polarization with High-Spin Transition Metal Ions

B. Corzilius et al., High-Field Dynamic Nuclear Polarization with High-Spin Transition  Metal Ions, 2011, JACS


We report the dynamic nuclear polarization of  1H spins in magic-angle-spinning spectra recorded at 5 T and 84 K via the solid effect using Mn2+ and Gd3+ complexes as polarizing agents. We show that the magnitude of the enhancements can be directly related to the effective line width of the central (mS = -1/2, 1/2) EPR transition. Using a Gd3+ complex with a narrow central transition EPR line width of 29 MHz, we observed amaximum enhancement of ∼13, which is comparable to previous results on the narrow-line-width trityl radical.