Peptide Bonds in the Interstellar Medium: Facile Catalytic Formation from Nitriles on Water-Ice Grains.

A recent suggestion that acetamide, CHC(O)NH, could be readily formed on water-ice grains by the acid induced addition of water across the C≡N bond has now been shown to be credible. Computational modeling of the reaction between R-CN (R = H, CH) and a cluster of 32 molecules of water and one HO proceeds catalytically to form first a hydroxy imine R-C(OH)═NH and second an amide R-C(O)NH. Quantum mechanical tunneling, computed from small-curvature estimates, plays a key role in the rates of these reactions.