Phthalocyanine-based multi-dimensional conductors

Electrochemical oxidation of [CoIII(Pc)X2]− yields highly conducting partially oxidized salt crystals. Their crystal structures and dimensionality of the π–π interaction (electronic system) vary by the cationic species in the salts; one-dimensional for TPP (tetraphenylphosphonium) or PTMA (phenyltrimethylammonium) cations, and ladder and two-dimensional for the PXX (peri-xanthenoxanthene) radical cation. Substitution of the axial group (X) or extension of the π-conjugated macrocycle (Pc) has been found to influence the magnitude of the π–π stacking interactions. Their electrical properties characterized by the conductivity and thermoelectric power measurements are found to be dependent on the dimensionality and the magnitude of π–π stacking interactions.