One-handed helical twisting in optically inactive poly(phenylacetylene) bearing two hydroxyl groups upon the departure of a single enantiomer

Abstract

Herein, we describe a novel macromolecular single-handed helical twisting in dynamic optically inactive polyphenylacetylene (poly(1)), bearing two hydroxyl groups, upon the nonracemic amines moving away from the polymer backbone, rather than in the presence of chiral guests. Two methodologies based on the departure of chiral guests from dynamic helical poly(1) were proposed to achieve a completely one-handed helix. First, the preferred-handed helical poly(1) could be observed after the gradual removal of chiral molecules from the solution using a concentration-driven permeation through a membrane. Furthermore, in a solution of poly(1)/toluene/chiral amine, the nonhelical cis-transoidal conformation at low temperatures twisted into a one-handed helical cis-cisoidal one by the removal of the chiral amine from the polymer backbone by heating the solution. Both these methodologies produce one-handed helical polymers that can well memorize helical sense in the solid state. The effect of amine content on one-handed helical formation was then investigated from the perspectives of dynamics and thermodynamic, respectively.