Helical magnetism in poly(aniline-<i>co</i>-ferrocene): structure and magnetism

This study reports the synthesis and characterisation of a ferrocene-based conjugated polymer and a chiral composite. The precursor copolymer was synthesised from 1,3-phenylenediamine and 1,1'-dibromoferrocene <i>via</i> Buchwald-Hartwig polycondensation. This polymerisation process increased the effective conjugation length and led to magnetic spin interactions along the main chain, resulting in a ground triplet spin state at 25 °C. Furthermore, the polymer was oxidised with <i>m</i>-chloroperoxybenzoic acid and doped with sulfuric acid. A chiral polymer blend was also prepared by combining the copolymer with hydroxypropyl cellulose to form helical polymer liquid crystals. The physical properties of these polymers were analysed using superconducting quantum interference devices, optical spectroscopy, electron spin resonance, and X-ray fluorescence spectroscopy. The resulting polymer blend exhibits helical magnetism. This approach to fabricating a chiral magnetic material from an achiral polymer <i>via</i> supramolecular chirality introduces a new method for preparing chiral magnets.