Tin(IV) porphyrin functionalization of electrochemically active fluoride-doped tin-oxide (FTO) via Huisgen [3+2] click chemistry
A novel tetra-alkyne terminated tin(IV) porphyrin 3 was synthesized in good yields and characterized using NMR spectroscopy, high resolution mass spectrometry and X-ray crystallography, the latter revealing interactions with hexane molecules that stabilize the crystal structure of the tin(IV) porphyrin 3. It was then linked to a conductive fluorine-doped tin oxide (FTO) surfaces using Huisgen [3+2] click chemistry. The attachment of the tin(IV) porphyrin to the FTO surface 6 was characterized by X-ray photoelectron spectroscopy (XPS), indicating the presence of the 1,2,3-triazole unit. Electrochemical measurements of the tin(IV) porphyrin modified FTO surface 7 show that it is still electrochemically active with oxidation (Epa) and reduction peaks (Epc) for the ferricyanide redox couple observed at Epc and Epa of -0.144 and +0.568 V vs. Ag | AgCl respectively, representing a modest shift of ca . +/- 0.1–0.15 V, compared to unmodified FTO.