摘要:
In an attempt to evaluate the steric effect of ortho methyl groups on the stability of the cumyl radical, 2,2',4,4',6,6'-hexamethylazocumene (6) was synthesized and its rate of decomposition was measured. The fact that 6 decomposes 40 times faster than azocumene is attributed to a ground state steric effect. Calculations on the mesitylcumyl radical 1 and cation 2 show both systems to be substantially nonplanar with dihedral angles of 48 degrees and 35 degrees, respectively. Calculated charge distributions for cation 2 corroborate previously obtained NMR results which showed substantial loss of charge delocalization.(1)