Fig. 1. Structures and names of the radicals investigated in this study. Synthetic routes are given in the ESI.† The proton enhancement factors measured in bulk solution of d8-glycerol/D2O/H2O 60/30/10 (v/v/v) at 18.8 T and 40 kHz MAS frequency are reported at a concentration of 5 and/or 10 mM. The sample temperature has been carefully calibrated at 110 ± 5 K. Experimental details are given in the ESI.†.
