Understanding α-lipoic acid photochemistry helps to control the synthesis of plasmonic gold nanostructures.

We propose the photopolymerization of lipoic acid (LA) as an novel approach to produce a cross-linked polymeric matrix of lipoic acid monomers (PALA) which helps to control the size of plasmonic gold nanostructures when using 3,3,6,8-tetramethyl-1-tetralone as the photo-initiator for the reduction of Au(III) to Au. A complete characterization of the polymer is included, and the dual behaviour of LA as an in situ stabilizer and reducing agent is investigated. These findings are relevant to the understanding of the photochemical transformation of this biologically relevant compound and would benefit the increasing use of LA and PALA for the synthesis of various nanomaterials.