Extending helicity—capturing the helical character of longer ortho-phenylene ethynylene oligomers

Abstract

New ortho-phenylene ethynylene oligomers are shown to fold into helices of up to two full turns. Evidence of folding is shown by both 1D NMR, where π–π stacking is explored through both solvent and temperature titrations, as well as by 2D ROESY NMR which confirmed folding but also showed the dynamic nature of these helices through the flipping of the terminal TMS group into and out of a hydrophobic pocket created when the helix forms.