Liquid crystalline polyacetylene derivatives with stable radical group

Di-substituted polyacetylene was synthesized by introducing both liquid crystalline (LC) group and stable radical group into side chains. Di-tert-butylphenol derivative, where the hydroxy moiety of the phenyl group was protected by trimethylsilyl group, was adopted as a stable radical precursor. Acetylene monomer substituted with the LC group and the radical precursor was polymerized using metathesis catalyst of TaCl5-(n-Bu)4Sn. The polymer was soluble in organic solvents and showed an enantiotropic smectic phase. ESR spin intensity of the polymer was evaluated after the radical precursor was deprotected and oxidized.