COMPARISON OF POLYDIPENTYLSILYLENES AND POLYDIPENTYLSILOXANES CONTAINING CHIRAL GROUPS

Polydipentylsilylene and -siloxane copolymers, containing bis[(S)-(+)- 2-methylbutyl]silane units have been synthesized. Thermal analysis dem onstrated for both types of copolymers that crystallization was hinder ed on incorporation of the 2-methylbutyl groups. Optical rotation meas urements in various solvents yielded a much stronger optical activity of the polysilylene copolymers, compared to the polysiloxanes. This ef fect has been explained by the formation of a chiral supramolecular st ructure in the case of the polysilylenes. The measurements have indica ted that the solvent quality can be employed to enhance the formation of this structure at relatively low 2-methylbutyl contents.