Self-Assembling Phenylpropyl Ether Dendronized Helical Polyphenylacetylenes

The first example of a self‐assembling phenylpropyl ether based dendronized polymer has been reported and its preferred helical handedness has been determined. Dendronized polymer poly(10) and its nondendritic analogue poly(8) are high‐cis‐content polyphenylacetylenes (PPAs) prepared by using [Rh(nbd)Cl]2/NEt3 (nbd: 2,5‐norbornadiene). Both polymers possess a stereocenter in their side chain, which selects a preferred helical handedness. Based on negative exciton chirality observed in the CD spectra of poly(10), we have designated this molecule as a right‐handed helical polymer, which persists over a wide temperature range. Poly(10) self‐organizes into both ${{\Phi}{{{\rm io}\atop {\rm h}}}$ and Φh lattices in bulk. The ${{\Phi}{{{\rm io}\atop {\rm h}}}$‐to‐Φh transition is associated with thermoreversible cis‐cisoidal to cis‐transoidal isomerization of the helical PPA, accompanied by a dramatic decrease in the column diameter and a decrease in the π‐stacking correlation length along the column. A model for the right‐handed helical dendronized PPA has been proposed wherein dendrons from adjacent column strata interdigitate to effectively fill space. Helical polymers with known handedness: A new class of self‐organizing cylindrical polymers based on phenylpropyl ether based self‐assembling dendrons is described (see figure). The helical handedness of these dendronized polyphenylacetylenes has been determined by using the exciton chirality method. Opportunities for the advance of new concepts in sensors and in electronics and to improve understanding of the emergence of macromolecular and supramolecular chirality are presented.