TY - JOUR
T1 - Diversity in the 1/2 spin arrangement of [Ni(dmit)2]- anions in divalent Ca2+ (crown ether) supramolecular cation salts
AU - Akutagawa, Tomoyuki
AU - Akutagawa, Tomoyuki
AU - Akutagawa, Tomoyuki
AU - Takamatsu, Nobuhiro
AU - Shitagami, Kozo
AU - Hasegawa, Tatsuo
AU - Hasegawa, Tatsuo
AU - Nakamura, Takayoshi
AU - Nakamura, Takayoshi
AU - Nakamura, Takayoshi
AU - Inabe, Tamotsu
AU - Fujita, Wataru
AU - Awaga, Kunio
AU - Awaga, Kunio
PY - 2001
Y1 - 2001
N2 - 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.
AB - 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.
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U2 - 10.1039/b101873f
DO - 10.1039/b101873f
M3 - Article
AN - SCOPUS:0034853112
SN - 0959-9428
VL - 11
SP - 2118
EP - 2124
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
IS - 9
ER -