Synthesis of Organic-inorganic Hybrid Dendrimers Based on Caged Silsesquioxanes as Cores and Application for Solid-state Functional Materials

Abstract

Octakis(propenyl succinicanhydrido)polyhedral octasilicate (OS-SA), which is prepared by hydrosilylation of octadimethylsiloxy-polyhedral octasilicate with propenyl succinic anhydride, is an attractive intermediate to produce a variety of octasilicate (OS)-cored dendrimers. The OS-core dendrimers are ideal candidates for single component functional solid-state materials, which possess three-dimensional well-defined molecular level structures. As these dendrimers have globular conformations due to the rigid OS core, their three-dimensional structures are maintained in the solid state. Especially, terminal function groups are isolated and inhibit interaction with neighboring branches. This review focuses on recent efforts to prepare single component functional solid-state materials based on the OS-core dendrimers. The OS-cored dendrimers bearing biphenyl or carbazole units on their terminal groups formed thermoplastic transparent free-standing films at room temperature. Bi-functional terminal OS-cored dendrimers bearing carbazole and 1,8-naphthalimide or fluorocarbon and hydrocarbon chains on their peripheries were synthesized by combination of ring-opening and condensation reaction of OS-SA with 9H-carbazole-9-ethanol and N-(2-hydroxyethyl)-1,8-naphthalimide or 9-decanol and perfluoro-1-decanol, respectively. The bi-functional terminal OS-cored dendrimers showed not only individual properties of the functional units but new functions derived from interaction between the two units.