Sauvee, C., et al., Highly Efficient, Water-Soluble Polarizing Agents for Dynamic Nuclear Polarization at High Frequency. Angew Chem Int Ed Engl, 2013. 52(41): p. 10858-10861.
Well polarized: Two new polarizing agents PyPol and AMUPol soluble in glycerol/water mixtures are used for dynamic nuclear polarization (DNP) NMR spectroscopy. The enhancement factors (epsilon) are about 3.5 to 4 times larger than for the established agent TOTAPOL at 263 and 395 GHz. For AMUPol, the temperature dependence of epsilon allows DNP experiments to be performed at temperatures significantly higher than for typical high-field DNP NMR experiments.