TY - JOUR
T1 - Structures of Ni(dmit)2 salts of lithium or ammonium included in crown ether assemblies
AU - Akutagawa, Tomoyuki
AU - Nakamura, Takayoshi
AU - Inabe, Tamotsu
AU - Underhill, Allan E.
N1 - Funding Information:
This work was partly supported by a Grant-in-Aid for Science Research from the Ministry of Education, Science, Sports and Culture. T.N. gratefully acknowledges support of the Association for the Progress of New Chemistry.
PY - 1998
Y1 - 1998
N2 - Three kinds of [Ni(dmit)2] (dmit = 2-thioxo-1,3-ditiol-4,5-dithiolate) salts containing 12-crown-4, 15-crown-5 or 18-crown-6 were prepared. In the crystal, the crown ethers form supramolecular assemblies in which counter cations are included. Lithium ions are located in the dimeric penta-coordinated ion cavity of [Li+]2[12-crown-4]3 unit of the [Li+]2[12-crown-4][Ni(dmit)2] 7[acetone]2 crystal. Each Li+ cation is coordinated by four oxygen atoms of a 12-crown-4 molecule and the oxygen of a second 12-crown-4 molecule which form a bridge to a further Li+ cation. Two 15-crown-5 molecules sandwich a NH+4 cation in the salt of [NH+4][15-crown-5]2[Ni(dmit)2]. The NH+4 ion is deca-coordinated by oxygen atoms of 15-crown-5 through weak hydrogen bonding. The cation-crown ether unit forms a dimer resulting in a barrel-like supramolecular cation. The [NH+4][18-crown-6][Ni(dmit)2]3 complex is composed of segregated trimer stacks of Ni(dmit)2 and isolated ion-captured cavities of [NH+4][18-crown-6]. The NH+4 ion is fully included in the cavity, and is tightly bounded through strong hydrogen bonds to the oxygen atoms of 18-crown-6, resulting in a disk-shaped supramolecular cation. The salts of [Li+]2[12-crown-4]3[Ni(dmit)2] 7[acetone]2 and [NH+4][18-crown-6][Ni(dmit)2]3 show semiconducting behaviour with the room-temperature conductivities of 30 and 0.4 S/cm, respectively, while [NH+4][15-crown-5]2[Ni(dmit)2] is insulating due to the mono-cation state of [Ni(dmit)2].
AB - Three kinds of [Ni(dmit)2] (dmit = 2-thioxo-1,3-ditiol-4,5-dithiolate) salts containing 12-crown-4, 15-crown-5 or 18-crown-6 were prepared. In the crystal, the crown ethers form supramolecular assemblies in which counter cations are included. Lithium ions are located in the dimeric penta-coordinated ion cavity of [Li+]2[12-crown-4]3 unit of the [Li+]2[12-crown-4][Ni(dmit)2] 7[acetone]2 crystal. Each Li+ cation is coordinated by four oxygen atoms of a 12-crown-4 molecule and the oxygen of a second 12-crown-4 molecule which form a bridge to a further Li+ cation. Two 15-crown-5 molecules sandwich a NH+4 cation in the salt of [NH+4][15-crown-5]2[Ni(dmit)2]. The NH+4 ion is deca-coordinated by oxygen atoms of 15-crown-5 through weak hydrogen bonding. The cation-crown ether unit forms a dimer resulting in a barrel-like supramolecular cation. The [NH+4][18-crown-6][Ni(dmit)2]3 complex is composed of segregated trimer stacks of Ni(dmit)2 and isolated ion-captured cavities of [NH+4][18-crown-6]. The NH+4 ion is fully included in the cavity, and is tightly bounded through strong hydrogen bonds to the oxygen atoms of 18-crown-6, resulting in a disk-shaped supramolecular cation. The salts of [Li+]2[12-crown-4]3[Ni(dmit)2] 7[acetone]2 and [NH+4][18-crown-6][Ni(dmit)2]3 show semiconducting behaviour with the room-temperature conductivities of 30 and 0.4 S/cm, respectively, while [NH+4][15-crown-5]2[Ni(dmit)2] is insulating due to the mono-cation state of [Ni(dmit)2].
KW - Crown ether
KW - Crystal structure
KW - Electrical conductivity
KW - Ni(dmit) complex
KW - Supramolecular cation
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U2 - 10.1016/S0040-6090(98)00929-8
DO - 10.1016/S0040-6090(98)00929-8
M3 - Article
AN - SCOPUS:0032181155
VL - 331
SP - 264
EP - 271
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
IS - 1-2
ER -