1005191-09-2Relevant academic research and scientific papers
Self-assembling phenylpropyl ether dendronized helical polyphenylacetylenes
Percec, Virgil,Peterca, Mihai,Rudick, Jonathan G.,Aqad, Emad,Imam, Mohammad R.,Heiney, Paul A.
, p. 9572 - 9581 (2008/12/20)
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-nor-bornadiene). 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 ΦhiO and Φh lattices in bulk. The ΦhiO-to-Φh transition is associated with thermore-versible 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.
