Influence of the Substitution Pattern Effect in Achiral and Rigid Spacers over the Folding of Helical Poly(phenylacetylene)s

The design, synthesis and structure elucidation of helical polymers with a predominant helical sense have been actively studied during the last years due to the different applications that these materials can present. The helical sense of a polymer can be determined by the chirality of the pendants and is directly related to the distance from the chiral centre to the backbone. In order to achieve the best folding this distance between the polymeric backbone and the chiral centre should be small, so the closer is the pendant to the backbone the better is the helical control. Nevertheless, few examples have demonstrated that the helical control is also possible when a spacer is placed between the pendant and the backbone. Related to this, our research group has proved that is possible to have chiral teleinduction when the chiral centre is separated form the backbone through a flexible spacer. Recently, we have also demonstrated that the transmission of information is also possible when a long rigid and achiral spacer is employed observing that, although the chiral centre is placed in a remote position, its chirality is transmitted to the polyene backbone through a previous organization into a helical fashion of the rigid spacer.

Herein we describe another family of polymers bearing an achiral rigid spacer between the pendant and the backbone, evaluating the effect that the aromatic substitution pattern of the rigid spacer has over the final folding of the polymer.