SYNTHESES OF INTERCALATION COMPOUNDS OF LAYERED NIOBATES WITH METHYLVIOLOGEN AND THEIR PHOTOCHEMICAL BEHAVIOR

Intercalation of methylviologen (1,1'-dimethyl-4,4'-bipyridinium ion) into two layered niobates (K4Nb6O17 and HNb3O8) and the photochemical behavior of the resulting compounds were investigated. UV irradiation of the intercalation compounds caused photoinduced electron transfer from the hosts to the guest; the formation of methylviologen radical cations was observed. This behavior was affected by the structure of the intercalation compounds. The radical cations were less stable in HNb3O8, where they were more densely packed, than in K4Nb6O17. Co-intercalation of photoinactive species with methylviologen significantly stabilized the radical cations in both of the hosts. The differences in the photochemistry apparently arises from structural differences.