Synthesis, characterisation and structural investigations of iodine-doped indium(III) and zirconium(IV) diphthalocyanines: [InPc2]I2 and [ZrPc2]I2

Crystals of iodine-doped indium(III) and zirconium(IV) diphthalocyanines, [InPc2]I2 and [ZrPc2]I2, were grown directly in the reaction of In–Tl alloy or zirconium powder with 1,2-dicyanobenzene under a stream of iodine at about 200 °C. Both partially oxidised diphthalocyaninato complexes crystallise in the P4/mcc space group of the tetragonal system with one molecule per unit cell. The space group of P4/mcc requires that the central metal ions are disordered in these structures. The crystal structures shown columnar pseudo-one-dimensional stacks of [InPc2] or [ZrPc2] units with a non-integral charge and linear chains of symmetrical triiodide I3 − ions, which were detected by a Raman spectroscopy. The pseudo-one-dimensional aggregates of [InPc2]2/3+ or [ZrPc2]2/3+ as well as the chains of I3 − ions are aligned along the [001] direction. The formal oxidation state of the Pc macrorings equals to ≅−1.167 and ≅−1.667 in indium(III) and zirconium(IV) diphthalocyaninato complexes. The EPR measurement shows a single sharp EPR line at g=2.0028 and 2.0026 for the indium and zirconium complexes, respectively. The conductivity measurement on polycrystalline samples at room temperature equals 2.7–3.1×10−2 and 5.2–5.5×10−2 Ω−1 cm−1 for [InPc2]I2 and [ZrPc2]I2, respectively. The charge transport proceeds mainly along the pseudo-one-dimensional [MPc2]2/3+ aggregates. Both iodine-doped metallodiphthalocyaninato complexes exhibit non-metallic character in conductivity (dσ/dT>0).