Cyclopolymerization of Disiloxane-Tethered Divinyl Monomers To Synthesize Chirality-Responsive Helical Polymers

• DOI: 10.1021/acs.macromol.5b02142
• Publication Date: 2016-01-07T18:27:56Z
• Authors: Junjiang Li; Min Du; Zhongqiang Zhao; Hewen Liu
• Keywords: Side chain; Chirality; Helix (gastropod); Vibrational Circular Dichroism

Synthetic polymers mimicking the stimuli-responsive coiled-coil structures of naturally occurring macromolecules such as motor proteins remain challenging. Here we report that chirality switchable quasi-double helical can be synthesized by free radical cyclopolymerization tetramethyldisiloxane-tethered divinyl monomers. Two cyclopolymers (pbSt and pbMA) are obtained in this work, which solid state investigated both ECD VCD. According to VCD analysis, C–H deformation modes including bending (mode I) rocking II) main-chain helix show strong signals spectra plots division IR, have different responses solvation histories or thermal treatment compared with other vibrational arising from side rings (especially tetramethyldisiloxane groups). After treatment, all side-ring pbSt pbMA inverted, while mode II main chain unchanged. In cast films chloroform solutions, shows only inverted I helix, but not any rings. Ab initio quantum calculation reveals change orientation distortion against may account for inversion signals. The experimental thus rationalized based on results. helices remained unchanged, changed their during treatment. polymer was hence VCD; might randomly distorted, causing loss Overall, pseudohelices switched independently. This work presents first example a single macromolecule display (quasi-)double-helical conformation. Besides theoretical value, kind quasi-double-helical find application asymmetric catalyst, smart molecular devices, etc.