Synthesis of helical polyisocyanides bearing aza-crown ether groups as pendant

We, herein, present a novel synthesis of responsive helical poly(aryl isocyanide)s bearing aza-crown ethers as pendant groups. Chiral aryl isocyanide monomers bearing an aza-crown ether as a pendant were designed and synthesized, piror to polymerization using a Pd-Pt mu-ethynediyl complex as an initiator to give the corresponding polymers in good yield. The resulting polyisocyanides adopted a stable helical structure in solution, as confirmed by circular dichroism spectroscopic analysis. In addition, the polymers were soluble in various solvents. Furthemore, the addition of suitable alkali metal ions to the crown ether of the sidechain on the helical polyisocyanide to form host-gest complexes resulted in deformation of the helix due to electrostatic repulsion, and these phenomena depended on the size of metal cations. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 496-504.