Water boosts light-driven coupling chemistry

Organic chemists have tended to avoid using water to host reactions, largely because their carbon-based molecules rarely dissolve in the liquid. Now, Burkhard König at the University of Regensburg has turned that insolubility into an advantage. His team has found that a thin film of organic molecules floating on top of water provides the ideal location for light-driven coupling reactions that could be used to modify drug candidates and produce agrochemicals. Interactions between the organic and water layers actually accelerate these reactions, which do not require organic solvents, catalysts, or heat ( Science 2024, DOI: 10.1126/science.adl3092 ). Chemists already knew that stirring a suspension of insoluble organic molecules in water can sometimes give reactions a boost. These are known as on-water reactions (rather than in water) , because they take place at the interface where organics and water meet. The reactions run faster for various reasons : the hydrophobic organic