ELECTRON-TRANSFER IN ZEOLITES - FORMATION OF AMINIUM AND BIPYRIDINIUMCATION RADICALS

Tris-(p-bromophenyl)amine is adsorbed on zeolite HY(Si/Al= 17) and the Na+ ions are exchanged by methylviologen dications on NaY (Si/Al=2.6) . The sorbed molecules are examined by high resolution solid state C-1 3 nuclear magnetic resonance with rotation at the magic angle in order to compare the chemical shifts in the adsorbed state to those of the solids and the solutions. Molecular graphics illustrate the adsorption of the molecules in Y zeolite. When the samples are evacuated at 150- degrees-C, free radical cations are readily formed. Their presence is detected by electron paramagnetic resonance and by the colour change.