Chemists at the University of California, Riverside have stabilized a highly reactive carbene molecule in water, proving a 67-year-old hypothesis about vitamin B1's role in the body. The breakthrough, detailed in Science Advances, resolves a long-standing biochemical puzzle. It also suggests potential for greener chemical manufacturing.
Researchers led by Vincent Lavallo at UC Riverside created a protective molecular structure, described as a 'suit of armor,' that shields the carbene from water. This allowed them to isolate the molecule, seal it in a tube, and observe it remaining stable for months. They analyzed it using nuclear magnetic resonance spectroscopy and x-ray crystallography, providing direct evidence of its existence in aqueous conditions. Lavallo called it 'the first time anyone has been able to observe a stable carbene in water,' confirming Ronald Breslow's 1958 proposal that thiamine, or vitamin B1, forms a carbene-like structure to drive biochemical reactions. Breslow, a Columbia University chemist, had suggested this despite carbenes' known instability, especially in water. First author Varun Raviprolu, a former graduate student at UCR now at UCLA, noted their work was initially exploratory but ended up validating the theory. The achievement opens doors to using carbenes in water-based catalysts for pharmaceuticals and fuels, avoiding toxic solvents. Raviprolu emphasized water's benefits as an abundant, non-toxic solvent for greener chemistry. Lavallo, with two decades of carbene research, highlighted the personal milestone: 'Just 30 years ago, people thought these molecules couldn't even be made. Now we can bottle them in water.'