Chiral supramolecular nanotubes of single-chain magnets.

Abstract

We report a Single-Chain Magnet (SCM) made of a Terbium(III) building block and a nitronyl-nitroxide radical (NIT) functionalized with an aliphatic chain. This substitution is targeted to induce a long range distortion of the polymeric chain and accordingly it gives rise to chains that are curled with almost 20\xa0nm helical pitch. They self-organize as a chiral tubular superstructure made of 11 chains wound around each other. The supramolecular tubes have a 4.5\xa0nm internal diameter. Overall, this forms a porous chiral network with almost 44% porosity. Ab-initio calculations highlight that each TbIII ion possesses high magnetic anisotropy. Indeed, notwithstanding the supramolecular arrangement each chain behaves as a SCM. Magnetic relaxation with both finite and infinite-size regimes is observed and confirms the validity of the Ising approximation. This is associated with quite strong coercive field and magnetic remanence (Hc\xa0=\xa02400\xa0Oe MR\xa0=\xa02.09\xa0µB at 0.5\xa0K) for this class of compounds.