Factors affecting the metallic versus semiconducting properties of charge transfer salts containing [M(dddt)2]2 and [M(dmit)2]2 (M = Pd, Pt) dimers

Molecular Conductors and Superconductors Based on Trihalides of BEDT-TTF and Some of Its Analogues

“…160 Only HOMO of ET contributes to the conduction bands of its salts, whereas both HOMO and LUMO of the M(dddt) 2 complexes can be involved in the conduction bands of their salts.…”

“…The difference in conducting properties is associated with the dimerization of the Pt(dddt) 2 cations in the stacks, as it is evident from the calculations of electron band structures of M(dddt) 2 salts. 160 It should be noted that the dimerization degree depends on the anion. As compared to [Pt(dddt) 2 ] 2 IBr 2 , the dimerization of the cations in [Pt(dddt) 2 ] 2 AuBr 2 , which is isostructural to the former salt, is stronger (the Pt‚‚‚Pt distance is 2.983 Å).…”

First-principles study of the neutral molecular metalNi(tmdt)2

“…Very soon this proposal received experimental support ͑diffuse X-ray scattering, 8 13 C Knight shift, 9 magnetic susceptibility, 10 species in the solid state, there is the possibility of an internal electron transfer which thus can make unnecessary the presence of the doping species. The structural and electronic requirements for the realization of a two-band behavior were explored, [11][12][13][14] and metal bis͑dithiolene͒ systems were proposed to be the more promising species in order to lead to single-component molecular metals. 14 Consequently, although Tanaka et al 5 apparently did not notice these developments, the discovery by these authors is certainly a remarkable experimental achievement but hardly an unexpected one since Ni(tmdt) 2 is a metal bis͑dithiolene͒ species ͓see Fig.…”

Molecular Conductors Based on M(dddt)2 Bisdithiolene Cation Complexes

“…For the M(dddt) 2 complexes, the energy gap between HOMO and LUMO is small (B0.4 eV), while in ET LUMO lies considerably higher in energy than HOMO (B2 eV) (21). Only HOMO of ET plays a role in the conduction bands of its salts, whereas both HOMO and LUMO of the M(dddt) 2 complexes can be involved in those of their salts.…”

“…The cations in the dimers are arranged face-to-face and the M-M distances are equal to 3.0-3.3 ( A depending on the anion. Though the Pt(dddt) 2 and Pd(dddt) salts with the linear IBr 2, ICl 2 , AuBr 2 anions have the same stoichiometry (2:1) as metallic and superconducting b-ET salts with these anions and their layered crystal structures are similar, the former is a semiconductor unlike the latter as a result of the Pt(Pd)(dddt) 2 strong dimerization in the stacks (10,11,21,23).…”