Polyacetylenes with cholesteryl side-groups: synthesis, linear and non-linear optical properties of soluble conjugated polymers

摘要: New polyacetylenes with cholesteryl side-groups different spacer lengths are polymerized through classical metathesis reaction in solution the transition metal halides WCl6, MoCl5, and TaCl5. The highest polymerization yield best average molecular weight obtained 4-pentynoate (CP5) 1 ,4-dioxane/WCl6 couple measured values are, respectively, 87% 15 · 104. All of other esters, propynoate or 10-undecynoate give low yields. Poly(CP5) is a red transparent solid; it can be dissolved common organic solvents cast from into films. solid-state film presents to thermotropic liquid-crystalline phase at 189°C isotropic 189°C. A progressive decoloration occurs phase. results interpreted as conformational changes polyene planar chain less conjugated backbone. third-order susceptibility χ3 by third harmonic generation on polymer lies range 10−21 V2·m−2 accord content active part molecule moderate length conjugation this highly crowded polyacetylenic chain.