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. Author manuscript; available in PMC: 2019 May 23.
Published in final edited form as: Angew Chem Int Ed Engl. 2018 Dec 20;58(5):1334–1339. doi: 10.1002/anie.201810522

Figure 5.

Figure 5

The 13C polarization solid-state build-up (left panel) and liquid-state relaxation (right panel) are showed for TriPA_DNP-sample, d9-TriPA_DNP-sample and Trityl_DNP-sample. Solid-state measurements were performed at 6.7 T and 1.1 K by mw irradiation at 188.19 GHz (20 MHz amplitude modulation and 1 kHz frequency modulation) for TriPA_DNP-sample and d9-TriPA_DNP-sample; Trityl_DNP-sample was polarized at the 187.94 GHz (no microwaves modulation) corresponding to the optimum for Trityl (see Supporting Information). Liquid-state measurements were acquired on 9.4 T high resolution magnet equipped with a 5 mm NMR probe kept at 40 °C. The transfer of the HP solution from the polarizer to the high resolution magnet took 10 s. In the inset the HP [U-13C,d7]-D-glucose NMR spectrum corresponding to the first point of d9-TriPA_DNP-sample signal decay is reported (C2-C5 DNP enhancement = 41000).