Two Polymorphs of (Anilinium)(18-Crown-6)[Ni(dmit)2]: Structure and Magnetic Properties |
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| Authors: | Sadafumi NishiharaTomoyuki Akutagawa Tatsuo Hasegawa Shigeki FujiyamaToshikazu Nakamura Takayoshi Nakamura |
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| Institution: | a Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japanb Research Institute for Electronic Science, Hokkaido University, Sapporo, 060-0812, Japanc Institute for Molecular Science, Okazaki, 444-8585, Japan |
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| Abstract: | Two polymorphs of monovalent Ni(dmit)2]− (dmit2−=2-thioxo-1,3-dithiole-4,5-dithiolate) crystals A and B, (anilinium)(18-crown-6)Ni(dmit)2], were prepared, and the structure and magnetic properties were investigated. In these crystals, the Ni(dmit)2]− molecules form dimers, which arranged into chains between the supramolecular cation structure (anilinium)(18-crown-6). In crystal A, supramolecular cation formed a regular stack, inducing ladder structure of Ni(dmit)2], whose magnetism had been well fitted by spin ladder equation with the spin gap of Δ=190 K. Crystal B is ca. 3% more densely packed compared to crystal A. Due to the dense packing, supramolecular cation stack is distorted, which prevented the intermolecular interaction between Ni(dmit)2]− dimers in direction corresponds to the ladder-leg direction in crystal A. Reflecting the Ni(dmit)2]− arrangement, crystal B showed a temperature dependence of magnetic susceptibility well reproduced by the singlet-triplet thermal activation model, whose antiferromagnetic exchange interaction (2J) was 140 K. |
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| Keywords: | [Ni(dmit)2] polymorph spin ladder magnetic properties crystal structure supramolecular cation 18-crown-6 |
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