Syntheses of Intercalation Compounds of Layered Niobates with Methylviologen and Their Photochemical Behavior

Intercalation of methylviologen (1, 1ʹ-dimethyl-4, 4ʹ-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.