SUMMARYSymmetrically and unsymmetrically substituted diorganodichlorosilanes have been prepared by hydrosilylation with dichlorosilane using two different platinum catalysts, i. e., hexachloroplatinic acid ("Speier's catalyst") and a platinum cyclovinylmethylsiloxane complex. Hydrosilylation of unsubstituted 1-alkenes proved to be very efficient, yielding anti-Markonikov substituted din-alkyldichlorosilanes. However, no reaction was observed when electron-deficient 1 -alkenes were used. Octacarbonyldicobalt enabled formation of the monoadduct of 1 H, lW,2H-perfluoro-lhexene with dichlorosilane, which was employed in a second hydrosilylation of the olefin. Thus, the anti-Markovnikov diadduct was obtained in 40% overall yield. The two-step synthesis has also been applied successfully to obtain unsymmetrically substituted diorganodichlorosilanes containing nitrile and ether groups.

SUMMARY Dichlorosilanes with ethyloligoglycoxypropyl substituents were synthesized from dichlorosilane and the respective allyl compounds. Wurtz-type coupling reaction led to a series of ether substituted polysilylenes with a distinct amphiphilic character. Formation of high molecular weight polymers becomes increasingly difficult as the length of the ether substituents is increased.

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Telechelic polysilylenes have been developed involving the chemical degradation of poly-(di-n-hexylsilylene) with bromine. The molecular weight of the newly formed telechelic PDHS depends on the ratio of bromine to the starting PDHS. The percentage of end groups increases as the molecular weight of the telechelic PDHS is lowered, reaching a maximum of 99% difunctionality. Polystyrene-PDHS-polystyrene triblock copolymers have been prepared by coupling polystyryllithium to the telechelic PDHS in the presence of cryptand [2.1.1]. The effect of molecular weight on the disordering transition of PDHS into a columnar mesophase has been studied, and temperature and enthalpy have been shown to decrease by the presence of the PS end groups and eventually became unobservable at high fractions of PS. The morphologies of the triblock copolymers were studied by atomic force microscopy.

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