Solid State Structures and Thermochromism of Poly(di-n-butylsilane) and Poly(di-n-pentylsilane).

The relationship between the solid state structures and the electronic absorption properties in polysilanes is of widespread interest. We report the solid state analyses of two symmetrically substituted polysilanes, poly(di-n-butylsilane) (PDBS) and poly(di-n-pentylsilane) (PDPS), based upon measurements using X-ray diffraction, sup (13) C and sup (29) Si NMR, UV, and calorimetry. The results indicate similarities in the structure and the electronic absorption properties of the polymers but differences in these properties as compared to those reported previously for poly(di-n-hexysilane) (PDHS). The polymers have been examined above and below the solid state disordering transitions, and a correlation is observed between the polymer chain conformation and the UV absorption maxima.