Preparation and photochemical behavior of polyfluorinated cationic azobenzene-titanoniobate intercalation compounds

A novel photofunctional material composed of polyfluorinated cationic azobenzene and layered potassium titanoniobate was synthesized and its photochemical behavior was investigated. Although polyfluorinated cationic azobenzene could not be intercalated into the interlayer region of layered potassium titanoniobate directly, the intercalation compound was obtained by guest-guest-exchange with the hexylammonium-TiNbO5 intercalation compound. X-Ray diffraction, TGA, IR, TEM, UV-visible spectroscopy and elemental analysis results indicated that the polyfluorinated cationic azobenzene was intercalated into the interlayer spaces of the potassium titanoniobate. The AFM image for the intercalated compound with a basal spacing of 3.90 nm was consistent with the X-ray diffraction data. The spectral properties as well as X-ray diffraction results have revealed that the adsorbed polyfluorinated cationic azobenzene molecules form J-like aggregates with bi-layers in the interlayer space of the potassium titanoniobate. The intercalation compound exhibited an excellent reversible cis-trans photoisomerization by successive illumination with UV light at 365 nm and visible light at 458 nm. The basal spacing changed reversibly upon photoisomerization of the intercalated polyfluorinated cationic azobenzene.