Facile reduction of sodium and bipyridinium cations within zeolites with Tesla spark-coil

The formation of tetrasodium ionic cluster (Na43+) and cation radicals of methylviologen (MV+.) and diquat (DQ+.) occurs readily within zeolites X and Y upon exposure of the corresponding cation-exchanged zeolites to a stream of sparks generated from a Tesla coil under vacuum. Although the reduced species are stable at 77 K, they disappear slowly at room temperature. From the strong dependency of the decay rates of bipyridinium cation radicals on their reduction potentials, the electropositivity of co-exchanged alkali metal cations, and the framework Si/Al ratio, the electrons ejected from zeolite frameworks are proposed to act as reductants.