Conducting neutral radical crystals of axially substituted phthalocyanine: crystal structures, dimensionality and electrical conductivity
Abstract
Electrocrystallization of the dicyanophthalocyaninatocobalt(III) anion, [Co(Pc)(CN)2]–, in a mixed solvent of acetonitrile and chloroform gives conducting neutral radical crystals of Co(Pc)(CN)2·2CHCl3. Similarly, that in a mixed solvent of acetonitrile or benzonitrile and water yields crystals of Co(Pc)(CN)2·2H2O. Since the molecule has two axial projections at the centre, a simple one-dimensional columnar structure cannot be formed. Instead, the crystal containing chloroform has two-dimensional sheets of phthalocyanines, and that containing water has a three-dimensional network of phthalocyanines. Their electrical resistivities are remarkably low as neutral radical crystals: that of Co(Pc)(CN)2·2H2O is the lowest of the π-based neutral radical crystals reported to date.
- This article is part of the themed collection: Molecular Conductors