Synthesis, structure, and spectroscopic and electrochromic properties of bis(phthalocyaninato)zirconium(IV)

Abstract
The crystal structure of the title compound [Zr(pc)2] has been solved by X-ray diffraction techniques. The cell is triclinic, P; a= 13.410(2)Å, b= 13.400(7)Å, c= 16.340(11)Å, α= 68.68(1)°, β= 65.92(1)°, γ= 74.74(1)°, R= 0.039 and R′= 0.058 for 6576 reflections. The infrared spectrum and details of the solvent dependence of the electronic absorption spectrum are also given. [Zr(pc)2] has the most distorted rings of all the metal bisphthalocyanines so far reported. The distortion is primarily caused by the Zr–N distances (average 2.30 Å), which though long for such Zr bonding, are very small when compared to other M–N bonds in similar structures. Cyclic voltammograms of [Zr(pc)2] are presented and discussed. The distorted structure has a detrimental effect on the electrochromic properties of the molecule, aiding decomposition during oxidation.