Photochemical Control of Polydopamine Coating in an Aprotic Organic Solvent

Catechols have been widely used in organic chemistry because of their high reactivities and binding affinities to metal ions. Various transformations, such as etherification and oxidation, have been developed to modulate their reactivity. Among these, the photochemical protection and deprotection of catechols has attracted significant research attention because of the mild reaction conditions employed in the transformations. Herein, we demonstrate the application of photolabile protection of the catechol functionality in dopamine for exploring promising applications in surface coating. The hydroxyl groups in dopamine were protected with the photolabile 2-(2-nitrophenyl)propoxycarbonyl protecting groups, that can be conveniently removed by exposure to UV light. Notably, upon deprotection, the free dopamine was polymerized to polydopamine in the presence of pyridinium chlorochromate, an organic oxidizing agent, and adhered to solid surfaces.