New class of metal BIS-dithiolene electroconducting solids: Cation complexes of metals with dddt

Structural, electrical, magnetic, and optical properties of bis-benzene-1,2-dithiolato-Au(IV) crystals

“…7 The gold-dithiolene complexes-though much less studied than the Ni dithiolenes-are known in a range of oxidation states. [8][9][10][11][12][13][14][15][16][17][18][19] As shown in the present paper, the oddelectron compound bis-͑benzene-1,2-dithiolato͒-gold ͓Au͑bdt͒ 2 ͔ belongs to the group of planar molecules, which in the solid state form electrically ͑semi͒conducting molecular stacks with a half-filled electronic band. A more wellknown member of this group is K-TCNQ ͑tetracyanoquinodimethane͒.…”

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

“…Whereas the metal-metal-or metalsulfur-bonded dimers of bisdithiolenes are widely known (13), the formation of metal-sulfur-bonded trimeric bisdithiolene was first found. The [M(dddt) 2 ] 3 2+ trimers are packed in stacks in the crystals of the salt 1 (8,11). There are no intertrimer shortened contacts in the stacks, whereas there are shortened side-by-side S?S contacts (3.36-3.66 ( A) between the stacks as in the ET 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).…”

“…However, the crystals grew on an anode instead of a cathode. The X-ray analysis of these crystals showed them to be the M(dddt) 2 cation salt in a partially oxidized state and have the [Ni(dddt) 2 ] 3 (ClO 4 ) 2 (1) composition (7,8,11). The salt is almost an insulator (sD 10 À5 S cm À1 ) as a result of the formation of Ni-S-strongly bonded trimeric cations [Ni(dddt) 2 ] 3 2+ (Fig.…”

“…Interest in the M(dddt) 2 complexes newly arose in the early 1990, when it was, for the first time, found that the neutral M(dddt) 2 complexes behave like ET, i.e. form electroconducting cation salts in a partially oxidized state under electrochemical oxidation (8)(9)(10)(11). It should be noted that the discovery of stable M(dddt) 2 cation salts was unexpected since the neutral complexes have high irreversible (or quasi-reversible) oxidation potentials (E0.9 V vs Ag/AgCl) (12).…”