Direct Grafting of Free-Base meso-Triarylporphyrins on Electrode Materials through Diazonium Reduction: Reversible Zinc(II) Metallation of the Resulting Materials

Electroreduction of free base meso-diazonium-triarylporphyrins, generated in situ from their corresponding meso-aminotriaryl-porphyrin precursors, leads to the formation of a covalently grafted porphyrin film. In this new material, contrary to recently published results, the free base porphyrin core is directly bonded to the surface, that is, without any spacer such as phenyl fragments. These thin films are characterized by cyclic voltammetry (CV), UV/Vis absorption spectroscopy and water angle contact. The electrochemical response is in agreement with a multilayer structure. Efficient and reversible zinc metallation of the immobilized porphyrin units is readily achieved opening the door to numerous applications in sensing and electrocatalysis.