A bis(imino)pyridine iron bisalkoxide complex that was previously shown to electrochemically toggle between two oxidation states so as to effect redox-switchable polymerizations of lactide and cyclohexene oxide was explored for surface initiated and redox-controlled polymerization reactions. Using a protonolysis reaction that occurs between a bis(imino)pyridine iron bisalkyl complex and titanium hydroxides, the iron complex was covalently anchored onto titanium oxide nanoparticles that was subsequently affixed to a semiconducting fluorine doped tin oxide (FTO) support.  The electrode surfaces facilitated surface initiated and redox-controlled ring-opening polymerization reactions of lactide and cyclohexene oxide. Similar reactivities were found in the surface anchored complex compared to the homogeneous complex. In its iron(II) oxidation state, the complex was able to catalyze lactide polymerization but displayed no reactivity towards cyclohexene oxide. Upon applying an oxidizing potential to the surface, the resulting iron(III) complex was no longer active for lactide polymerization and became active for cyclohexene oxide polymerization. The chemoselectivity that application of different potentials affords was explored for patterning titanium oxide surfaces, wherein chemical functionalization was dictated by the electrochemical bias applied to the surface. <br/>

Patterning surface-initiated polymer growth by an electrochemical redox switch

2019 Fall National Meeting

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