Diversity in the 1/2 spin arrangement of [Ni(dmit)2]- anions in divalent Ca2+ (crown ether) supramolecular cation salts

Tomoyuki Akutagawa, Tomoyuki Akutagawa, Tomoyuki Akutagawa, Nobuhiro Takamatsu, Kozo Shitagami, Tatsuo Hasegawa, Tatsuo Hasegawa, Takayoshi Nakamura, Takayoshi Nakamura, Takayoshi Nakamura, Tamotsu Inabe, Wataru Fujita, Kunio Awaga, Kunio Awaga

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Abstract

Calcium ion (Ca2+) and crown ethers, 12-crown-4, 15-crown-5, 1-aza-18-crown-6 (A18-crown-6) and 1,10-diaza-18-crown-6 (DA18-crown-6), were assembled into divalent supramolecular cation (SC2+) structures in the monovalent [Ni(dmit)2]- salts (dmit2-=2-thioxo-1,3-dithiole-4,5-dithiolate), which regulate the arrangement of the [Ni(dmit)2]- anions in the crystal. The divalent SC2+-[Ni(dmit)2]- system showed a larger diversity of crystal structures compared with the monovalent SC+ system. Peculiar magnetic behavior was observed depending on the arrangement of the S=1/2 spins on the [Ni(dmit)2]- anions. Single crystals of Ca2+(12-crown-4)2[Ni(dmit)2]2 (1) and Ca2+ (15-crown-5)2[Ni(dmit)2]2(CH3CN) 0.7 (2) had a typical sandwich-type Ca2+ (crown ether)2 structure, which included the formation of π-π dimers and monomers of [Ni(dmit)2]- anions in the crystal. The temperature-dependent magnetic susceptibility (χm) of salt 1 showed a magnetic transition at 190 K, at which temperature the spins on each [Ni(dmit)2]- dimer formed a singlet pair. On the other hand, the magnetic behavior of salt 2 obeyed the Curie-Weiss law. The Ca2+ ions in the isostructural single crystals of Ca2+(A 18-crown-6)[Ni(dmit)2]2(CH3CN)2 (3) and Ca2+ (DA18-crown-6)[Ni(dmit)2]2(CH3CN) 2 (4) were completely included into the 18-crown-6 cavity, and further interacted with two CH3CN molecules from the axial position. The resultant Ca2+(18-crown-6)(CH3CN)2 cations induced the formation of uniform zig-zag chains of the [Ni(dmit)2]- anions, the magnetic susceptibility of which were explained by a one-dimensional Heisenberg antiferromagnetic linear chain. The magnetism of these salts was discussed in terms of the intermolecular transfer integral t.

Original languageEnglish
Pages (from-to)2118-2124
Number of pages7
JournalJournal of Materials Chemistry
Volume11
Issue number9
DOIs
Publication statusPublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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    Akutagawa, T., Akutagawa, T., Akutagawa, T., Takamatsu, N., Shitagami, K., Hasegawa, T., Hasegawa, T., Nakamura, T., Nakamura, T., Nakamura, T., Inabe, T., Fujita, W., Awaga, K., & Awaga, K. (2001). Diversity in the 1/2 spin arrangement of [Ni(dmit)2]- anions in divalent Ca2+ (crown ether) supramolecular cation salts. Journal of Materials Chemistry, 11(9), 2118-2124. https://doi.org/10.1039/b101873f