CHEMISTRY WORLD - A new ‘super-shielded’ carbene is stable in liquid water solutions. The US team that made the carbene claims that it ‘unambiguously confirms’ that it is possible to generate carbenes in an aqueous environment – validating a hypothesis put forward almost 70 years ago by the famed organic chemist Ronald Breslow.
In the late 1950s, Breslow proposed that vitamin B1 was able to promote various biochemical reactions via the formation of a fleeting carbene species. But this was a controversial idea as carbenes are not generally thought to be compatible with water. While much indirect evidence gathered over the years has led the scientific community to accept Breslow’s hypothesis, until now no carbene had been directly observed in an aqueous solution.
Vincent Lavallo, whose lab at the University of California, Riverside isolated the new water-stable carbene, explains that the project began almost a decade ago. ‘We design catalysts as part of my research programme, and [carbenes] often can be used as supporting parts of catalysts as ligands,’ he explains. ‘And this one turns out to be a horrible ligand – doesn’t bind anything, doesn’t react with anything. But that’s why we can isolate it.’