Semiconducting Anion-radical Salts Derived from 3,3′5,5′-Tettrahalo-p-diphenoquinones

Abstract

Abstract 3,3′5,5′-Tettrahalo- and 3,3′,5,5′-tetrabromo-p-diphenoquinones were found to form series of complex anion-radical salts of the M+(Q2)− or M+2(Q3)2− type with various onium cations. These complex salts are darkcolored, almost black in many cases, and show electronic absorptions extending into the rock-salt region. In addition, bluish green-colored simple salts could be isolated with a few cations. The complex salts exhibit electrical resistivities in orders from 10 to 104 ohm cm at room temperature. Neither the pattern due to the quinone molecule nor that due to the semiquinone ion is present in their vibrational spectra. A single carbonyl stretching vibration band appears around 1600 cm−1, intermediate between that in the quinone and that in the semiquinone salt.