Fig. 4: EPR data for 5 and 6.

a X-band (9.8 GHz) EPR spectrum of 5 at 298 K as a 9 mM solution in THF. The black line is the experimental spectrum and the red line the simulation with g = 2.003, A(11B) = 9.44 G, A(10B) = 2.7 G, A(1H) = 1.2–1.4 G. b X-band (9.3 GHz) EPR spectrum of a powdered sample of 6 at 20 K. The black line is the experimental spectrum and the red line the simulation with g = 4.19, 0.88, and 0.52. The very sharp signal marked with asterisk is a very small quantity of radical impurity with g = 2.