Ferromagnetic and Antiferromagnetic Coupling of [Ni(dmit)2]−Anion Layers Induced by Cs+2(benzo[18]crown-6)3Supramolecule

Abstract

Sandwich-type (Cs(+))(2)(benzo[18]crown-6)(3) and (Cs(+))(dibenzo[18]crown-6)(2) supramolecular cations were introduced as counterions of [Ni(dmit)(2)](-) (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate) anions to induce unique [Ni(dmit)(2)](-) anion (S = 1/2) arrangements and magnetic properties. The magnetic exchange energy (J) between the [Ni(dmit)(2)](-) anions was dependent on the mode of the intermolecular interactions. In the case of (Cs(+))(2)(benzo[18]crown-6)(3)[Ni(dmit)(2)](-)(2) (1), the asymmetric arrangement of the [Ni(dmit)(2)](-) anions involved the coexistence of a pi-dimer chain along with a two-dimensional layer via lateral S...S contacts, in which the magnetic properties of the pi-dimer chain and the two-dimensional layer were characterized by antiferromagnetic (J = -5.2 K) and ferromagnetic coupling (Weiss temperature = +1.1 K), respectively. The unique [Ni(dmit)(2)](-) arrangements and magnetic behaviors for crystal 1 can be attributed to the asymmetrical benzo[18]crown-6. In the case of Cs(+)(dibenzo[18]crown-6)(2)[Ni(dmit)(2)](-) (2), however, the formation of the lateral [Ni(dmit)(2)](-) dimer via S...S contacts yielded antiferromagnetic coupling corresponding to the dimer model (J = -25.5 K).