Crystallographic and (spectro)electrochemical characterizations of cobalt(II) 10-phenyl-5,15-di-p-tolylporphyrin

•Investigation of the electrochemical behavior of cobalt(II) 5,15-p-ditolyl-10-phenylporphyrin (1-Co) by cyclic voltammetry.•Characterization of the electrogenerated Co(III) porphyrin by RDE voltammetry and UV-vis absorption spectroscopy.•Comparison of the crystallographic structure of 1-Co with existing cobalt (II) meso-tetraphenylporphyrin (CoTPP) and with the corresponding 1-Zn and 1-Ni complexes.•The X-ray crystallographic structure revealed various types of interactions between the porphyrins: aromatic cycle stacking between two porphyrins, CH-π and metal-π interactions. The synthesis, cyclic and rotating disk electrode voltammograms, UV-visible absorption and X-ray diffraction analyses of cobalt(II) 10-phenyl-5,15-di-p-tolylporphyrin (1-Co) are described. 1-Co was crystallized by slow diffusion of n-hexane into a concentrated CH2Cl2 solution. X-ray diffraction analyses reveals porphyrin aromatic cycle stacking in the crystal, C-H···π interactions of the CH2Cl2 solvent with the π-system of one tolyl group and Co(II)···π (porphyrin ring) interactions. The abstraction of 1.0 F/mol during the electrolysis at the first oxidation potential was followed by spectroelectrochemistry. It leads to the Co(II) → Co(III) transformation rather than the formation of the cation radical of the porphyrin ligand. These results were supported by comparison of the cyclic and rotating disc electrode voltammograms, of the UV-Visible absorption spectra, before and after electrolysis of 1-Co. [Display omitted]