Synthesis of organic-inorganic hybrid compounds and their self-assembled behavior in different solvents

Self-assembly behavior of polyoxometalates (POMs) is influenced by the functional group linked with polyoxometalates structure. We modified the POMs with organic molecule terpyridine to endow POMs the ability to assemble into nanostructure and control the properties of POMs. An amphiphilic organic-inorganic hybrid compound was prepared through combining the 4'-para-phenylcarboxyl-2,2':6',2''-terpyridine (PPCT) with POM to form the (TBA)₃POM-PPCT. After cationic exchange, tetrabutylammonium cation (TBA⁺) can be turned into H⁺ to produce H₃POM-PPCT. H₃POM-PPCT showed excellent self-assembly behavior in different solvents. By adjusting the proportion of solvents, different fibers and leaf-like aggregates were obtained, which were determined by SEM and TEM observations. According to the experimental observations, mechanism of the formation of nanostructures was established. The redox properties of POMs can be maintained after the modification with PPCT, which were demonstrated by cyclic voltammetry (CV) measurements. The successful synthesis of these POMs may provide us an opportunity to find more functionalized ramifications of POMs, with self-assembled structures controlled in different solvent, but the interesting properties of these novel POMs can also provide motivation and guidance for the further development of novel functionalized POMs.