Abstract
A conducting partially oxidized salt of TPP[Fe(Pc)(CN)2]2, which contains paramagnetic iron(III), has been obtained by electrocrystallization of TPP[Fe(Pc)(CN)2]. The crystal is composed of one-dimensional TPP arrays surrounded by slipped-stacked one-dimensional Fe(Pc)(CN)2 chains. This structure is isomorphous with TPP[Co(Pc)(CN)2]2, in which the central metal is non-magnetic cobalt(III). The electrical conductivity at room temperature, ca. 10 Ω−1 cm−1, is about one order of magnitude lower than that of the Co analogue. On lowering the temperature, the conductivity shows a much steeper decline compared with the temperature dependence of the conductivity of TPP[Co(Pc)(CN)2]2. The band width, estimated from both thermoelectric power measurements (which show apparent metallic behavior at high temperatures) and an extended Hückel calculation, is found to be the same as that obtained for TPP[Co(Pc)(CN)2]2. This is consistent with observations from the single-crystal reflectance spectra, in which both partially oxidized salts show almost the same plasma edge. On the other hand, the magnetic susceptibility of TPP[Fe(Pc)(CN)2]2 is quite different from that of TPP[Co(Pc)(CN)2]2; both of the magnetic moments originated from FeIII and the π-radical seem to be localized in TPP[Fe(Pc)(CN)2]2, while the moments originated from the π-radical in TPP[Co(Pc)(CN)2]2 are interacting with each other to lead to temperature-independent Pauli-like susceptibility. At low temperatures, a decrease in the susceptibility has been observed, suggesting the existence of antiferromagnetic interactions.
Please wait while we load your content...
