Synthesis and characterization of a liquid crystalline polyacetylene with cholesteryl side groups using Schrock-type molybdenum initiators

We report the synthesis and polymerization of a new acetylene monomer with a cholesteryl side group. The monomer shows monotropic behaviour. Polymerization is initiated with the well-defined Schrock-type molybdenum carbene Mo(CHR)(NAr)(OR′)2 with NAr = 2,6-dimethylaniline, R = C(CH3)2C6H5 and R′ = C(CH3)(CF3)2. Polymerization is almost quantitative and yields a polymer with a comparatively narrow molecular weight distribution. The material is an orange solid which is soluble in common organic solvents at room temperature. The results of DSC, X-ray diffraction, and polarizing optical microscopy (POM) indicate that, upon cooling, the polymer exhibits a mesophase of the smectic A type before undergoing a glass transition.