Highly Conducting Crystals Based on Single-Component Gold Complexes with Extended-TTF Dithiolate Ligands

Abstract

Highly conducting crystals based on single-component gold complexes with extended-TTF dithiolate ligands [Au(dmdt)(2)](0+) (1) and [Au(tmdt)(2)](0+) (2) were prepared (dmdt = dimethyltetrathiafulvalenedithiolate and tmdt = trimethylenetetrathiafulvalenedithiolate). On the basis of the synchrotron radiation powder diffraction data, the MEM electron density of 2 was successfully obtained. The conductivities of compacted powder samples of 1 and 2 at room temperature were 12 and 15 S cm(-1), respectively. Pauli-like susceptibility of 1 suggested the system to be essentially metallic at least above 50 K, while 2 showed a magnetic transition around 100 K without loss of its high conductivity.

Ab initio derivation of multi-orbital extended Hubbard model for molecular crystals

“…40 The atomic coordinates are read from the data of x-ray structure analysis. 19,26 Due to the presence of inversion center at the midpoint of the molecules, the resulting MOs can be classified into gerade (g) or ungerade (u) with respect to the inversion center. The energy spectrum was calculated using a restricted open-shell Hartree-Fock (ROHF) procedure.…”

“…From the x-ray structure analysis, it has been shown that the system exhibits another inversion center located at midpoint between two molecules. 19,26 For the inversion transformation around the midpoint, the wavefunctions of the two molecules follow the relations ϕ g,I (r) = ϕ g,II (−r), ϕ u,I (r) = −ϕ u,II (−r). The ϕ g, I , ϕ u, I , ϕ g,II , and ϕ u,II MOs are used to define the model space.…”

“…Among these singlecomponent molecular solids, the metallic behavior was first confirmed in [Ni(tmdt) 2 ]. 17,18 In [Au(tmdt) 2 ], antiferromagnetic ordering was observed with high transition temperature T AF = 110 K. [19][20][21] Interestingly, it has been proposed that in [Au(tmdt) 2 ], a new type of antiferromagnetic state, called the intra-molecular antiferromagnetic (IAF) state, is realized, in which two ligands within each molecule have opposite spins. 22,23 From DFT-based ab initio calculations for these compounds, several MOs are shown to contribute to the conduction band of the crystal systems.…”

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

“…130 They analyzed its purity by EPMA, which gives about one order less accuracy than the elemental analysis. Although numerous reports on highly conductive single component coordination compounds have appeared since 2000, [131][132][133][134][135][136][137][138][139][140] the characterizations of some compounds are insufficient to claim the metallic single molecular solid, concerning the purity, measurement conditions, experimental information, etc. Note that most authors stated that their material is a ''first single-component metal or good conductor,'' without mentioning pentacene and p-iodanil under pressure (see section 2.1) 17,24,25 or Tl 2 Pc at ambient conditions.…”

Kramers degeneracy in a magnetic field and Zeeman spin-orbit coupling in antiferromagnetic conductors

“…Recently synthesized ethylenedioxytetrathiafulvalenoquinone-1,3-diselenolemethide (EDO-TTFVODS), that appears to turn antiferromagnetic below about 4.5 K, and remains normal down to the lowest studied temperature of 0.45 K [75], may be another. Finally, recent studies [76][77][78] of [Au(tmdt) 2 ], where tmdt denotes trimethylenetetrathiafulvalenedithiolate, draw attention to this organic conductor. Albeit the material is not yet fully characterized, and its large single crystals remain difficult to grow, it appears to have a Néel temperature of about 110 K [77,78], which is anomalously high for an organic material -and shows normal conduction down to at least 10 K.…”