Synthesis and characterization of amphiphilic o-phenylene ethynylene oligomers†
Abstract
We have previously reported the synthesis of short o-phenylene ethynylene oligomers with polar triethylene glycol side chains which adopt a helical conformation in solution with three residues per turn. Two new oligomers have been synthesized, a hexamer and a nonamer, incorporating a repeated triad motif of polar–nonpolar–polar sidechains in order to create a hydrophobic stripe in the folded conformation which we report here for the first time. Helical folding in solution was observed and, unlike the previously-reported oligomers, these new oligomers are ordered solids at room temperature. Although these oligomers were designed to assemble into helical bundle-like structures, no evidence for a quaternary-like structure was found. The difference in polarity between