Carborane-silane polymers

FIGURE 26.22 Phenyl acetylene-terminated poly(carborane-silane) (PACS) polymer. 

Quan, Z. Zuju, M. Lizhong, N. Jianding, C. 2007. Novel phenyl acetylene terminated poly(carborane-silane) Synthesis, characterization, and thermal property. J. Appl. Polym. ScL, 104 2498-2503. 

The polymer where n is 2 can be prepared according to equation 3 in which a bis(hydroxysilyl)carborane is reacted with a blsureido silane where X is an N-phenyl-N -tetramethyleneureido group (3). 

For comparison, l,l -bis(dimethylsilyl)ferrocene 4a, l,l -bis(diphenylsilyl)ferrocene 4b and 1,4-bis(dimethylsilyl)benzene 5 were also prepared and reacted with vinyl polymer 1 to form hybrid polymers 6a, 6b and 7 respectively. In the case of 6a and 7, higher reactivities of the silanes lead to gelation. While electron deficient carborane seems to reduce Si H reactivity, the conjugation effect of the aromatic system on the silicon atoms may gain the Si-H reactivity. Phenyl-substituted 6b... 

Figure 3.15. Some siloxane chemistry (a) Silicates react with organic silane derivatives to form siloxanes. (b) Siloxanes may also be formed by partial hydrolysis of substituted silanes followed by heat treatment with a basic catalyst, (c) A highly refractory polymer consisting of a carborane-substituted siloxane.

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