RADICAL IONS .34. NOVEL ORGANOSILICON RADICAL CATIONS - ONE-ELECTRON OXIDATION OF PERMETHYLCYCLOPOLYSILANES

The permethylcyclosilanes 1-4, all of which exhibit low first ionization potentials, have been oxidized with AlC13 in CH2Cl2 to form the first examples of delocalized, Ω-electron radical cations. These species have been studied by ESR spectroscopy. Unlike the well-known radical anion of 1, the radical cation of dodecamethylcyclohexasilane (1+) gives an ESR spectrum which can be simulated only by assuming two sets of 18 equivalent protons, corresponding to 6 axial and 6 equatorial methyl groups which do not become equivalent on the ESR time scale. The high g value of 2.0093 observed for 1+ suggests a considerable spin population in the Si6 ring skeleton. The radical cations of 2, 3, and 4 show only overlapping signals in ESR, but their respective g values of 2.010, 2.0105, and 2.0063 are also consistent with spin derealization into the osi-Si system. © 1979, American Chemical Society. All rights reserved.