“…The EPR spectra of 9a-d show that the central group 13 metal atom and the NBN boron atoms have non-zero spin density values arising from polarization effects. The experimental spectra of these spirocyclic neutral radicals can, therefore, be simulated by assuming hyperfine interaction of the unpaired electron with four equivalent nitrogen centers, two boron atoms and the central group 13 element ( 27 Al, I = 5 / 2 , 100 %; 69 Ga, I = 3 / 2 , 60.1 %;71 Ga, I = 3 / 2 , 39.9 %; 113 In, I = 9 / 2 , 4.3 %;…”