A supramolecular cation of (m-FAni+)(DBcrown-6), where m-FAni+ and DBcrown-6 denote m-fluoroanilinium+ and dibenzocrown-6, respectively, which is the polar unit rotating in the ferroelectric crystal of (m-FAni+)(DBcrown-6)[Ni(dmit) 2]-, was introduced into a ferromagnetic [MnCr(oxalate)3]- salt as the counter cation. The crystal structure of (m-FAni+)(DBcrown-6)[MnCr(oxalate)3] -(CH3OH)(CH3CN) (1) is constructed from alternating layers of a two-dimensional honeycomb layer of [MnCr(oxalate) 3]- and (m-FAni+)(DBcrown-6) supramolecular cations. The anionic layer is composed of MnII and CrIII ions with S = 5/2 and S = 3/2 spins, respectively, bridged by the oxalate anions, which show ferromagnetic ordering at 5.5 K. The supramolecular structure is formed through the formation of hydrogen bonds between the ammonium hydrogen atoms of the m-FAni+ cations and the oxygen atoms of the DBcrown-6 cavity. No orientational disorder of the fluorine atoms was observed in our X-ray structural analysis, suggesting that a two-fold flip-flop motion of the m-FAni+ cations does not occur in the salt. The rotational freedom of the m-FAni+ cations in the salt is restricted by the steric hindrance from neighbouring DBcrown-6 molecules. A design strategy for the rotation in a salt is discussed, based on the volume that the supramolecular cations occupy in the unit cell.
ASJC Scopus subject areas
- Inorganic Chemistry