Structural, Magnetic, and Electrical Characterization of New Polycrystalline Phases of Nickel- and Platinum-Doped [(DT-TTF)n][Au(mnt)2] (n = 1, 2)
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- 作者：Xavi Ribas ; Angelo Sironi ; Norberto Masciocchi ; Elsa B. Lopes ; Manuel Almeida ; Jaume Veciana ; and Concepció ; Rovira
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：April 4, 2005
- 年：2005
- 卷：44
- 期：7
- 页码：2358 - 2366
- 全文大小：774K
- 年卷期：v.44,no.7(April 4, 2005)
- ISSN：1520-510X
文摘
Doping of spin-ladder systems by isostructural paramagnetic complexes was attempted. Despite the close isostructuralnature of the pure (DT-TTF)2[M(mnt)2] (M = Au, Ni, Pt) end-members, which present a ladder structure, doping ofthe spin-ladder (DT-TTF)2[Au(mnt)2] with either 5% or 25% [M(mnt)2]- (M = Ni, Pt) generates two (metrically) newphases. Their markedly different crystal structures have been determined using laboratory X-ray powder diffractiondata. (DT-TTF)2[Au0.75Ni0.25(mnt)2] consists of a mixed-valence compound (of triclinic symmetry), which was onlydetected, pure or in a mixture of phases, when [Ni(mnt)2]- was used as a dopant. Differently, the stoichiometric1:1 [DT-TTF][Au0.75Pt0.25(mnt)2] monoclinic phase was found when [Pt(mnt)2]- (in 5% and 25%) was employed asthe doping agent. Remarkably, only in the 5% Pt doping experiment, the major component of the mixture was theladder structure compound (DT-TTF)2[Au(mnt)2] doped with minor amounts of Pt. This 5% Pt-doped specimenshows an EPR signal (g = 2.0115, 
fchars/Delta.gif" BORDER=0 >Hpp = 114 G at 300 K) wider than the pure compound (DT-TTF)2[Au(mnt)2],denoting exchange between the donor spins and Pt(mnt)2- centers. The electrical transport properties of the 5%Pt-doped composition at high temperatures are comparable to those of (DT-TTF)2[Au(mnt)2] with room-temperatureconductivity fchars/sigma.gif" BORDER=0 >300K = 13 S/cm and thermopower S300K = 46 
f">V/K, with a sharp transition at 223 K similar to thatpreviously observed in the Cu analogue at 235 K.
fchars/Delta.gif" BORDER=0 >Hpp = 114 G at 300 K) wider than the pure compound (DT-TTF)2[Au(mnt)2],denoting exchange between the donor spins and Pt(mnt)2- centers. The electrical transport properties of the 5%Pt-doped composition at high temperatures are comparable to those of (DT-TTF)2[Au(mnt)2] with room-temperatureconductivity fchars/sigma.gif" BORDER=0 >300K = 13 S/cm and thermopower S300K = 46 f">V/K, with a sharp transition at 223 K similar to thatpreviously observed in the Cu analogue at 235 K.