New Materials based on Organosilicon Chemistry

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We report the formation of self-assembled micelles and shell-cross-linked micelles of amphiphilic polysilane block copolymers. Poly(1, 1-dimethyl-2, 2-dihexyldisilene)-b-poly-(methacrylic acid) (PMHS-b-PMAA) were prepared by sequential anionic polymerization of masked disilenes and then with trimethylsilyl methacrylate, followed by hydrolysis of the trimethylsilyl protecting group. PMHS-b-PMAA is soluble but obviously self-assembled in water to form polymer micelles. Since PMHS-b-PMAA has a reactive methacrylic acid block, a shell cross-linking reaction of the polymer micelles was examined to form shell-cross-linked micelles (SCM). Encapsulating and release of guest molecules for the nano-organization system were examined. In this system, the polysilane core is surrounded by a partially cross-linked shell of poly(methacrylic acid). Since the polysilane core part can undergo photochemical degradation, it is expected to provide hollow sphere particles (hollow shell cross-linked micelles, HSCM) by a photochemical process. The synthesis of nanometer-sized hollow particles derived from polysilane shell cross-linked micelles and demonstrates their macromolecular architectures that undergo reversible uptake of guest molecules are also examined.Next, we report the intramolecular dimerization of remotely generated silylenes in a molecule. Alpha, omega-bissilylene, such as 1, 6-disilahexane-1, 1, 6, 6-tetrayl, generated at low temperature undergo efficient intermolecular dimerization to give cyclic disilenes, 1, 2-disilacyclohexene-1. Cyclic disilenes are trapped by alcohols or 2, 3-dimethylbutadiene.