Polymorphism and Magnetism of (cis-Cyclohexane-1,4-diammonium)(Dicyclohexano[18]crown-6)₂[Ni(dmit)₂]₂ Salts

Supramolecular cationic structures of (CHDA 2+ )(DCH[18]crown-6) 2 were introduced into [Ni(dmit) 2 ] − salts (where CHDA 2+, DCH[18]crown-6, and dmit 2− represent cis -cyclohexane-1,4-diammonium, meso -dicyclohexano[18]crown-6, and 2-thioxo-1,3-dithiole-4,5-dithiolate, respectively). The crystal polymorphs of (CHDA 2+ )(DCH[18]crown-6) 2 [Ni(dmit) 2 ] 2 (crystals 1 and 2 ) within the same crystallization batch were classified in the space groups P 2 1 / n ( 1 ) and P 1̅ ( 2 ). The N−H + ∼O hydrogen-bonding interactions between the axial- and equatorial-ammonium moieties of the CHDA 2+ cation and the oxygen atoms of DCH[18]crown-6 yielded a sandwich-type 1:2 adduct of the supramolecular cation in 1 and 2 . Although the overall cationic structures in 1 and 2 resembled one another, the [Ni(dmit) 2 ] − anion arrangements were distinctively different from each other. The lateral [Ni(dmit) 2 ] − dimer along the short axis of the anion was observed in 1, whereas two types of [Ni(dmit) 2 ] − π-dimer existed independently in 2 . The weak intermolecular interactions between the [Ni(dmit) 2 ] − anions in 1 was reflected by the temperature dependent magnetic susceptibility, which followed the Curie−Weiss model. For 2, two different magnetic exchange energies arising from the different strengths of the π-dimer units dominated the magnetic properties.