NOVEL FLUORINATED SIGMA-CONJUGATED POLYSILYNES FOR OPTICAL WAVE-GUIDES

Fluorinated polysilynes were prepared by the reductive coupling of trichlorosilanes with molten sodium in a mixture of toluene and diglyme (4:1) as a new synthetic route. Homopolysilynes containing fluorinated organogroups were insoluble in organic solvents due to side reactions. To improve solubility, copolysilynes were synthesized by copolymerization of fluorinated trichlorosilanes with cyclohexyltrichlorosilane. All spectroscopic data indicate that the structure of the resulting polysilynes is a rigid, irregular network of monosubsituted sp(3)-hybrid silicon atoms that have three neighboring silicon atoms. They exhibit extensive Si-Si sigma-delocalization. Upon exposure to deep-UV radiation in air, they undergo photooxidative crosslinking to give insoluble glass-like materials. This photooxidation process is accompanied by a large decrease in refractive index from n= 1.61 to n= 1.485. These results suggest that their potential applications are as optical waveguides in optical interconnect systems.