Polysilanes Produced from Dehydrocoupling

A reasonable expectation for a transition metal catalyzed process would be the ability to control the micro structure of the product and in this case the polysilane, EI(RSiEI )VE 1, that is produced. An unusual selectivity seemed to be apparent in the condensation of PhSiH3 by bis(indenyl)- and bis(tetrahydroindenyl)zirconium dimethyl catalysts and was originally attributed to stereoregulation in the polymerization but was later proposed to be due to an unusual selectivity in the production of cyclics.36,79 In an earlier report17 of the condensation of PhSiH3 with rac- E BI)ZrCl2/2 BuLi 

An ab initio study of the geometries, polarizabilities, and rotational barriers of H(PhSiH) H oligomers has been reported.104 The trends in polarizabilities for isotactic and syndiotactic oligomers with = 4 8 were extrapolated to the infinite polymer limit. 

The reaction chemistry of the polysilanes (particularly those formed from PhSiH3) have been studied to a limited extent and will only be mentioned briefly here. The polysilanes, H(RSiH)raH, obtained from dehydrocoupling are air-sensitive producing a siloxane-type structure for the polymer 

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