Synthesis and characterization of semiconductive dichloridobis(thianthrene) gold(1+) Tetrachloridoaurate(1-)

A new (thianthrene)gold(III) complex has been synthesized in liquid SO ₂ as the solvent from, thianthrene (TA) and. AuCl₃. [AuCl₂(TA)₂][AuCl₄] [triclinic, P1́, a = 9.9832(2) Å, b = 10.3404(2) Å, c = 15.0798(4) Å, a = 75.038(1)°, β = 81.610(1)°, y = 68.409(1)°, V = 1396.15(5) ̊³, Z = 2] has a salt-like structure consisting of [AuCl ₂(TA)₂]⁺ and [AuCl₄]^- ions, both with square-planar coordinated gold atoms of oxidation state +3. In the cation, two bent TA molecules are coordinated, to Au each through one sulfur atom. The title compound is thermally stable up to 425 K and is semiconducting with a conductivity reaching 25 mSm^-1 at 380 K and a low activation energy of 0.43 eV. A model for the charge transport along the stacked cationic complexes is discussed. When dissolved in chloroform [AuCl₂(TA) ₂][AuCl₄] is converted into the already known uncharged, mononuclear complex [AuCl₃(TA)], which shows that a polymerization isomerism exists between the two forms.