Synthesis and Chiroptical Properties of Helical, Conjugated Polymers, and Twisted Molecules

This chapter discusses the synthesis, structure, and chiroptical properties including chirality circularly polarized luminesce of optically active polymers including polyurethanes, polyfluorenes, poly(fluorene-2,7-diylethene-1,2-diyl)s [poly(fluorenevinylene)s], and poly(benzene-1,4-diyl)s [poly( p -phenylene)s] having single-handed helical conformation as well as nonuniformly folded conformation in addition to small molecules having preferred-handed twisted conformation. Helical conformation is introduced to polymers by asymmetric polymerization of an optically active monomer in which smaller-scale chirality of monomer is transformed to larger-scale chirality of polymer conformation. As a newer method, circularly polarized light (CPL)-driven helix and twist conformation is also presented where chirality of the incident light is amplified through interactions between chains (molecules) and between chains and substrate. Optically active polymers and molecules prepared by these two methodologies exhibit efficient circularly polarized luminescence.