Three kinds of charge-transfer (CT) complexes of PXX (PXX = 6, 12-dioxaanthanthrene) have been newly prepared and structurally characterized. In the 1 : 2 CT complex with TNP (TNP = 2,4,6-trinitrophenol), PXX is practically neutral. In the semiconducting partially oxidized salt with I3, the PXX molecules form a trimer and each PXX is formally oxidized by e/3. In the 3 : 2 salt with [Ni(mnt)2]- (mnt = maleonitriledithiolate), the PXX molecules again form a trimer unit and each PXX is formally oxidized by 2e/3. Together with the structural data obtained from the PXX single component crystal, the molecular geometry change by the formal charge on PXX has been examined. A noticeable change has been found in the aromatic ring framework, which is consistent with the distribution of the HOMO coefficients obtained from the extended Hückel calculation.

A novel low-dimensional molecular conductor, [PXX][FeIII(Pc)(CN)2], has been synthesized. This salt contains the magnetic FeIII ion (S = 1/2), and is isomorphous with [PXX][CoIII(Pc)(CN)2] which includes the non-magnetic CoIII ion. In both salts, the [MIII(Pc)(CN)2] (M = Fe or Co) units form a two-leg ladder chain. The two salts exhibit a similar temperature dependence of the thermoelectric power and a similar reflectance spectrum. The FeIII salt shows semiconducting behavior in its electrical resistivity over the temperature range measured, while the isomorphous CoIII salt exhibits metallic behavior in its resistivity above 100 K. The difference in the transport properties between the two salts suggests that the conduction electrons in the FeIII salt are seriously scattered by the local magnetic moment. Spontaneous magnetization is observed below 8 K in the FeIII salt. Upon applying a magnetic field, the resistivity of the FeIII salt drastically decreases below 50 K. The decrease in the resistivity is highly anisotropic to the field orientation. The field orientation dependence is highly consistent with the g-tensor anisotropy in the [FeIII(Pc)(CN)2] unit, suggesting that the negative magnetoresistance originates from the large π–d interaction self-contained in the [FeIII(Pc)(CN)2] unit.

A novel phthalocyanine conductor containing 2-D π–π stacks of the partially oxidized Co(Pc)(CN)2 units has been obtained by the electrochemical oxidation method with PXX. The crystal is highly conductive (>103 S cm−1) at all the temperatures measured (5 K < T < 300 K). Though the metallic character becomes clearer compared with the single chain or ladder chain conductors, the 2-D sheet has been found to be still anisotropic.

Nearly isotropic two-dimensional sheets of partially oxidized Co(Pc)(CN)2 units were observed to form in a salt with PXX (PXX = peri-xanthenoxanthene), [PXX]2[Co(Pc)(CN)2]·CH3CN. The crystal is semiconducting under ambient pressure but displays stable metallic behavior under high pressure.

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