Synthesis, Isolation, and Structural Characterization of the <i>C</i><sub>4</sub><i><sub>h</sub></i> Isomer of Metal(1,2-naphthalocyanine) and Its One-Dimensional Conductor of the Axially Substituted Species

The <i>C</i><sub>4</sub><i><sub>h</sub></i> isomer of the 1,2-Nc (1,2-naphthalocyaninato) ligand has been efficiently isolated as a hydrated magnesium complex by the fractional crystallization from the benzene/acetone solution after treating the crude mixture of the four isomers (<i>C</i><sub>4</sub><i><sub>h</sub></i>, <i>C</i><i><sub>s</sub></i>, <i>C</i><sub>2</sub><i><sub>v</sub></i>, <i>D</i><sub>2</sub><i><sub>h</sub></i>) with benzene. The <i>C</i><sub>4</sub><i><sub>h</sub></i> symmetry has been confirmed by X-ray structure analysis. The central metal ion has been demetalated and subsequently converted to the Li<sub>2</sub> complex followed by conversion to the cobalt(II) complex. Electrochemical oxidation of the Co<sup>III</sup>(1,2-Nc)(CN)<sub>2</sub> anion prepared from the cobalt(II) complex with TPP (tetraphenylphosphonium) has yielded a partially oxidized salt, TPP[Co<sup>III</sup>(1,2-Nc-<i>C</i><sub>4</sub><i><sub>h</sub></i>)(CN)<sub>2</sub>]<sub>2</sub>. The crystal comprises slipped stacked Co<sup>III</sup>(1,2-Nc-<i>C</i><sub>4</sub><i><sub>h</sub></i>)(CN)<sub>2</sub> one-dimensional chains and one-dimensional arrays of TPPs. The conductivity at room temperature is 0.1 S cm<sup>-1</sup>, and the temperature dependence is semiconducting with a small activation energy of about 0.05 eV. The positive temperature-independent value of about 60 μV deg<sup>-1</sup> observed in the thermoelectric power measurements suggests that the salt is in the correlated hopping regime.