Lubrication is often key to getting a mechanical machine to work smoothly. For molecular machines that spin or ratchet through chemical reactions, lubrication takes on a new meaning. By experimenting with a molecular shuttle in acetonitrile and a wheel-and-axle device in pyridine, scientists have found that a small amount of water added to the solvents accelerates the amide-based machines’ movement, likely through hydrogen-bonding effects (Nat. Chem. 2013, DOI: 10.1038/nchem.1744). The team was led by Sander Woutersen and Matthijs R. Panman of the University of Amsterdam, in the Netherlands, and David A. Leigh of the University of Manchester, in England. Other additives capable of hydrogen bonding, such as methyl alcohol, ethyl alcohol, and tert-butyl alcohol, did not have the same effect. The researchers hypothesize that water’s small size and ability to form hydrogen bonds in multiple directions allows it to form and quickly rearrange hydrogen-bond networks between the moving parts of the machines to stabilize CO and NH groups. In that way, water facilitates—or “lubricates”—machine movement.