A highly conducting partially oxidized salt of axially substituted phthalocyanine. Structure and physical properties of TPP[Co(Pc)(CN)2]2 {TPP=tetraphenylphosphonium, [Co(Pc)(CN)2]=dicyano(phthalocyaninato)cobalt(III)}

Abstract

A highly conducting partially oxidized salt of TPP[Co(Pc)(CN)₂ ]₂ can be obtained by electrocrystallization of TPP[Co(Pc)(CN)₂ ]. The crystal is composed of one-dimensional TPP arrays surrounded by slipped-stacked one-dimensional [Co(Pc)(CN)₂ ] chains. The electrical conductivity at room temperature is quite high, 120 Ω^–1 cm^–1 , though at low temperature it is weakly semiconducting. The band width for this stacking mode has been estimated from both thermoelectric power measurements and an extended Hückel calculation. The latter suggests that the band width value for the slipped-stacking mode is about 40% of the value for the face-to-face stacking mode. The width estimated from the metallic temperature dependence of the thermoelectric power is actually in excellent agreement with that estimated from the calculation.