Water-soluble meta-poly(phenylene ethynylene) oligomers with stable helical secondary structure

Abstract

Two novel water-soluble meta-poly(phenylene ethynylene) (mPPE) copolymers were synthesized and characterized, each contained ester and amine functional groups attached to exohelix positions on the phenylene rings and one contained methoxy endohelix functional groups. Secondary structure formation was investigated for these materials in aqueous solutions using ultraviolet and fluorescence spectroscopy. Additionally, the folding behaviors are reported for the mPPEs and their protected amine precursors in other protic and aprotic solvents. Results indicate that both mPPEs are able to form stable helical structures in water, while only the nonmethoxylated polymer exhibited a helical structure in acetonitrile and several alcohols. © 2012 Wiley Periodicals, Inc.