摘要:
4-Methylanilinium derivatives were used to introduce spaces for molecular rotation in crystals. The [Ni(dmit)(2)](-) (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) salts with supramolecular cations of dibenzo[18]crown-6 (DB[18]crown-6) and 4-methylanilinium derivatives, (4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (1), (2-fluoro-4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (2), and (3-fluoro-4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (3) were synthesized. The potential energy curves for the molecular rotations of the cations in the crystals had double minimum shapes with maxima of 100, 210, and 230 kJ mol(-1) for crystals 1, 2, and 3, respectively. Introduction of a methyl substituent at the p-position was effective in reducing the potential energy maxima. For crystals 2 and 3, large dielectric responses originating from the flip-flop motions of the cationic molecules were observed upon applying an AC voltage. The temperature-dependent magnetic susceptibilities of complexes 1, 2, and 3 followed the Curie-Weiss law, showing weak antiferromagnetic interactions.