Supramolecular cations of HOPD+(crown-6) and HMPD +(crown-6) were introduced into [Ni(dmit)2] - salts (HOPD+: o-aminoanilinium, HMPD+: m-aminoanilinium, and dmit2-: 2-thioxo-1,3-dithiole-4,5-dithiolate). Alternate layers of cations and anions were observed in the two new salts of (HOPD+)(crown-6)[Ni(dmit)2]- (1) and (HMPD+)(crown-6)[Ni(dmit)2]- (2). From X-ray crystal structural analyses, solid state 1H nuclear magnetic resonance (NMR) spectra, and dielectric constants, the thermal rotations of crown-6 in both of the (HOPD+)(crown-6) and (HMPD +)(crown-6) supramolecules occurred at temperatures above ∼200 K based on the orientational disorder in the crystal structures. The two-fold flip-flop motions of HOPD+ and HMPD+ cations in salts 1 and 2 were suppressed, due to the relatively large potential energy barriers. The [Ni(dmit)2]- anion formed π-dimer arrangements in both salts, with a layer structure by lateral sulfur-sulfur interatomic contacts. Although the simple dimer model reproduced the magnetic properties of salt 1, the ladder arrangement of the π-dimer in salt 2 yielded the magnetic behavior of a spin-ladder with a spin-gap of 92.5 K. The temperature dependent magnetic susceptibility of salt 2 was well reproduced by the magnetic anisotropy of J1/J2≈ 8 between the ladder-leg (J1: intra-dimer interaction) and ladder-rung (J 2: inter-dimer interaction). The crown-6 supramolecular rotator of (HMPD+)(crown-6) was coexistent with the spin-ladder chain of [Ni(dmit)2]- anions in salt 2.
ASJC Scopus subject areas
- Inorganic Chemistry