Oxidative polymerization of zinc porphyrin using the electrochemical Langmuir-Blodgett trough.

Multielectron electrochemical oxidation of non-substituted zinc porphyrin yields a polymeric structure. We report the oxidative formation of polymerization nuclei using the electrochemical Langmuir-Blodgett (LB) trough and an STM-type electrode tip. The electrochemical method eliminates the need for an excess of a chemical oxidant. The electrochemical LB trough assembly, which we reported earlier, efficiently produces a large number of separated thin oxidized nuclei. Topographic profiles from STM images indicate their average height of 0.52 ± 0.04 nm. The most frequently observed islands have an average length of 11.6 ± 0.6 nm. Their growth follows the Volmer-Weber "island growth" model, yielding isolated islands of a new phase. These experiments confirm electrochemical oxidation as an alternative method for synthesizing thin porphene oligomers without an external oxidizing agent.