Inorganic Chemistry, Vol.57, No.16, 9644-9655, 2018
Ring-Oxidized Zinc(II) Phthalocyanine Cations: Structure, Spectroscopy, and Decomposition Behavior
A bromonium oxidizing agent was used to produce a ring-oxidized zinc phthalocyanine (PcZn), [PcZn-(solvent)]center dot(2)[BAr4F](2) (1 center dot solvent), in good yield. This material is dimeric in the solid state with one axially coordinated solvent [tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME)] and close intradimer ring-ring distances of 3.18 and 3.136 angstrom (THF and DME respectively); this proximity facilitates strong antiferromagnetic coupling to yield diamagnetic dimers. 1-THF is present in solution as a monomer and a dimer. In CH2Cl2, the dimer is favored above 0.1 mM, and it is almost exclusively present in solvents with a high dielectric constant such as acetonitrile. The material 1-THF/DME decomposes in DME to a meso-nitrogen-protonated species, [HPcZn(DME)(2)][BAr4F] (2), which was isolated and represents the first example of such a structurally characterized, protonated, unsubstituted PcM complex. A partially oxidized dimer or "pimer" [(PcZn(DME))(2)]center dot[BAr4F] (3) was also structurally characterized and has a intradimer ring-ring distance of 3.1921, similar to 1 center dot THF/DME. Dirner 3 also represents the first isolated PcM-based pimer. Electron paramagnetic resonance analysis of a 1.0 mM solution of 1 center dot DME in DME showed the production of 3 over hours by the combination of 1 center dot DME and 2 in solution.