First Synthesis of Isotactic Poly(9-alkyl1-9-alkyl2fluorene) via Directed Aryl-Aryl Coupling of Chiral AB-Type Monomers

Nonsymmetrically substituted chiral 9-alkyl(1)-9-alkyl(2)fluorene monomers of the AB type allow for their directed, stereoregular aryl-aryl cross-coupling after Suzuki leading to isotactic poly(9-alkyl(1)-9-alkyl(2)fluorene). As expected, the isotactic poly(9-dodecyl-9-methylfluorene) i-PF1-12 of this Study Shows all increased solid state ordering and distinctly different thermal properties when compared to its corresponding atactic, stereoirregular polyfluorene counterpart a-PF1-12. This and other isotactic polyfluorene derivatives will be interesting building blocks for the generation of chiral, all-conjugated block copolymers.