Photocatalytic Carboxylation of Organic Substrates with Carbon Dioxide at Zinc Sulfide with Deposited Ruthenium Nanoparticles

Abstract Photocatalytic carboxylation of acetylacetone with carbon dioxide has been performed by using ZnS‐based photocatalysts. The formation of two isomeric carboxylic acids, as proven by IR and 13 C NMR spectroscopy, was observed. The reaction yield was enhanced after deposition of ruthenium nanoparticles on ZnS. The reaction encompasses ruthenium‐mediated one‐electron reduction of CO 2 to CO 2 .− with electrons from the conduction band of ZnS and one‐hole oxidation of acetylacetone to the relevant radical. Coupling of photogenerated radicals leads to the formation of carboxylic acids. Generation of CO 2 .− has been confirmed by spin‐trapping EPR measurements. The process described herein may find applications for the solar‐light‐driven green synthesis of C n +1 carboxylic compounds from C n substrates by utilising carbon dioxide.