Conducting Dimerized Cobalt Complexes with Tetrathiafulvalene Dithiolate Ligands
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- 作者：Emiko Fujiwara ; Kazumasa Hosoya ; Akiko Kobayashi ; Hisashi Tanaka ; Madoka Tokumoto ; Yoshinori Okano ; Hideki Fujiwara ; Hayao Kobayashi ; Yuichi Fujishiro ; Eiji Nishibori ; Masaki Takata ; Makoto Sakata
- 刊名：Inorganic Chemistry
- 出版年：2008
- 出版时间：February 4, 2008
- 年：2008
- 卷：47
- 期：3
- 页码：863 - 874
- 全文大小：743K
- 年卷期：v.47,no.3(February 4, 2008)
- ISSN：1520-510X
文摘
To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinatedby TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of(nBu4N)2[Co(chdt)2]2 (1), (nBu4N)2[Co(dmdt)2]2 (2), [Co(dmdt)2]2 (3), and [Co(dt)2]2 (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF-dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealedthat two monomeric [Co(ligand)2]- or [Co(ligand)2]0 units are connected by two Co-S bonds resulting in dimeric[Co(ligand)2]22- or [Co(ligand)2]2 molecules. Complex 1 has a cation-anion-intermingled structure and exhibitedCurie-Weiss magnetic behavior with a large Curie constant (C = 2.02 K·emu·mol-1) and weak antiferromagneticinteractions (
= -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric moleculesare completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules ofcomplex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of 
rt =1.2 × 10-2 S·cm-1 and an activation energy of Ea = 85 meV. The magnetic behavior is almost consistent withCurie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10-2 K·emu·mol-1 and -0.85 K,respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large(rt = 19 S·cm-1), and its temperature dependence was very small (0.55K/rt = ca. 1:10), although the measurementswere performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility(
300 K = 3.5 × 10-4 emu·mol-1) from 300 to 50 K. The band structure calculation of complex 4 suggested themetallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecularstructure and essentially metallic properties down to very low temperatures.
= -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric moleculesare completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules ofcomplex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of rt =1.2 × 10-2 S·cm-1 and an activation energy of Ea = 85 meV. The magnetic behavior is almost consistent withCurie-Weiss law, where the Curie constant and Weiss temperature are 8.7 × 10-2 K·emu·mol-1 and -0.85 K,respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large(rt = 19 S·cm-1), and its temperature dependence was very small (0.55K/rt = ca. 1:10), although the measurementswere performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility(300 K = 3.5 × 10-4 emu·mol-1) from 300 to 50 K. The band structure calculation of complex 4 suggested themetallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecularstructure and essentially metallic properties down to very low temperatures.