(nBu4N)[Ni(dmstfdt)2]: A Planar Nickel Coordination Complex with an Extended-TTF Ligand Exhibiting Metallic Conduction, Metal-Insulator Transition, a
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- 作者：Emiko Fujiwara ; Kimiko Yamamoto ; Mina Shimamura ; Biao Zhou ; Akiko Kobayashi ; Kazuyuki Takahashi ; Yoshinori Okano ; Hengbo Cui ; Hayao Kobayashi
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：February 6, 2007
- 年：2007
- 卷：19
- 期：3
- 页码：553 - 558
- 全文大小：339K
- 年卷期：v.19,no.3(February 6, 2007)
- ISSN：1520-5002
文摘
The 1:1 tetrabutylammonium salt of a nickel complex with an extended-TTF ligand, (nBu4N)[Ni(dmstfdt)2] (dmstfdt = dimethyldiselenadithiafulvalenedithiolate) (1) is a unique ambivalent molecularsystem exhibiting weakly metallic conduction above room temperature and a weak ferromagnetism atlow temperature. Its X-ray structure consists of two independent [Ni(dmstfdt)2]- (A and B) and twonBu4N+ in the unit cell. The pseudo-planar anions are arranged in a zigzag -ABA'B'- manner along themolecular side-by-side direction with a dihedral angle of the molecular planes of 42.6
. The tight-bindingband structure calculation, based on transfer integrals estimated by the extended Hückel approximation,presents both three-dimensional electron and hole Fermi surfaces, which is consistent with the observedweakly metallic conduction around room-temperature despite the 1:1 stoichiometry of the complex. At147 K, 1 shows a sharp insulating transition associated with the localization of one electron on eachnickel complex below 160 K. The 
T values of 1 increase linearly from 0.129 to 0.383 emu K mol-1with decreasing temperature (160-340 K), suggesting a gradual electron localization with lowering thetemperature. In the range of temperature of 80-150 K, follows the Curie-Weiss law: = C/(T - 
);C = 0.383 emu K mol-1; and = -4 K. Weak ferromagnetism sets in below 20 K. The coercive fieldis ±1.3 kOe at 2.0 K.
. The tight-bindingband structure calculation, based on transfer integrals estimated by the extended Hückel approximation,presents both three-dimensional electron and hole Fermi surfaces, which is consistent with the observedweakly metallic conduction around room-temperature despite the 1:1 stoichiometry of the complex. At147 K, 1 shows a sharp insulating transition associated with the localization of one electron on eachnickel complex below 160 K. The T values of 1 increase linearly from 0.129 to 0.383 emu K mol-1with decreasing temperature (160-340 K), suggesting a gradual electron localization with lowering thetemperature. In the range of temperature of 80-150 K, follows the Curie-Weiss law: = C/(T - );C = 0.383 emu K mol-1; and = -4 K. Weak ferromagnetism sets in below 20 K. The coercive fieldis ±1.3 kOe at 2.0 K.