Foldaxane-Based Switchable [c2]Daisy Chains

Abstract

Artificial molecular muscles are highly attractive in the field of molecular machinery due to their unique properties of contraction and stretching motion. However, the synthesis of molecular muscles poses formidable challenges as it is hindered by undesirable yields and poor selectivity. Herein, we present a procedure for the dynamic assembly of foldaxane-based [c2]daisy chains, wherein the hermaphroditic sequences consisting of aromatic helices and peptide rods are interlocked through inter-strand hydrogen-bonding interactions. The binding complementarity facilitates a selective and efficient assembly of [c2]daisy chain structures, inhibiting the creation of by-products. Introducing multiple recognition sites confers the system with contraction and stretching motion actuated by chemical stimuli. The rate of this muscle-like motion is calculated to be 0.8 s^-1, which is 10⁷ times faster than that of complex dissociation.

Keywords: Cross-Threaded Structure; Foldamers; Foldaxanes; Molecular Muscles; Switchable Motion.