Abstract
Structures and properties of molecular conductors based on axially-ligated phthalocyanine complexes are presented. Electrochemical oxidationof [MIII(Pc)(CN)2]−, where Pc is phthalocyaninato and M = Co and Fe, gives partially oxidized salt crystals inwhich the π-π stacking structure depends on the cationic species. For the Co salts, charge disproportionation leads to thermally activated conduction in the one-dimensional π-π stacking conductors, while in the two-dimensional π-π stacking conductors, localization of charges is suppressed. For the Fe salts, carrier locarization always occurs due to enhanced charge disproportionation by the interaction between π-electrons (charge carriers) and localized d-spins. However, application of external magnetic fields induces remarkable reduction of the electrical resistivity, leading to giant negative magnetoresistance.
