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-dicyclohexanol[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 P2(1)/n (1) and PT (2). The N-11(+)similar to 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)](-) pi-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 pi-dimer units dominated the magnetic properties.