Stitching Siloxanes

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Science  15 Apr 2005:
Vol. 308, Issue 5720, pp. 327
DOI: 10.1126/science.308.5720.327a

Siloxane polymers are widely used for their rubbery character. The stiffness and durability of the materials are influenced by the side groups pendant from the main Si-O chain. However, polymerization conditions often restrict the structural versatility of the monomers.

Chauhan and Rathore use platinum nanoclusters as a hydrosilation catalyst to append terminal olefins to the Si-H branches of (methylhydro)siloxane polymers. The reaction proceeds in benzene at room temperature with 0.1% catalyst loading and shows remarkable functional group tolerance. In addition to aromatic and alkyl groups, olefins bearing carbonyls, epoxides, and ferrocene were all successfully incorporated. Analysis of the products by nuclear magnetic resonance spectro-scopy revealed strong regioselection (99:1 for nonaromatics) for Si bonding to the terminal carbon. — JSY

J. Am. Chem. Soc. 10.1021/ja042824c (2005).

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