Flexible supramolecular cation structures, [(XyDA)0.5(crown ethers)]+ complexes, were introduced as countercations to [Ni(dmit)2]- anions, which bear an S = 1/2 spin, to form novel magnetic crystals (XyDA = p-xylylenediammonium, dmit2- = 2-thioxo-1,3-dithiole-4,5-dithiolate, and crown ethers = crown-4, crown-5, or crown-6). Sandwich-type [(XyDA)0.5(crown ethers)]+ structures were formed through hydrogen-bonding interactions in the crystals between the ammonium moieties of XyDA and the oxygen atoms of the crown ethers. Crown-4 yielded three types of [(XyDA)0.5(crown-4)]+[Ni(dmit)2] polymorphs, whereas two types of [(XyDA)0.5(crown-5)]+[Ni(dmit)2] polymorphs were obtained using crown-5. Three types of [(XyDA)0.5(crown ethers)]+ structures were identified for these polymorphs. Since the flexible -CH2-NH3+ moieties connected to benzene plane have rotational freedom, the [(XyDA)0.5-(crown ethers)]+ structures varied according to the conformations of the XyDA cation in the crystals. The larger ring size of crown-6 than that of crown-4 and crown-5 reduced the flexibility of the XyDA cation, and provided only one type of crystal. The [Ni(dmit)2]- anion existed as dimer structures, which are in the singlet ground state. The arrangement of the [Ni(dmit)2]- anion in the crystals were depended on the structure of [(XyDA)0.5(crown ethers)]+. Correlation of the absolute values of magnetic exchange energy J to the square of the intradimer transfer integral t2 were confirmed.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry