Molecular Dynamics Simulation for Formamide Aqueous Solution

In order to know more about the microcosmic structure of the important biochemical model molecule formamide (FM) in aqueous solution, the Optimized Potentials for Liquid Simulations-All Atom (OPLSAA) model were used in the molecular dynamics (MD) simulation for the aqueous solution of FM in the whole concentration range. The radial distribution functions of the solutions were obtained. The interaction between water molecule and FM molecule was analyzed and calculated. It was found that there was a weak interaction (C-H...O) between the C-H beside the carbonyl of FM and water. The weak interaction could not be ignored, which was suggested to be significant in preventing the tautomerization of FM, especially when the concentration of FM increased in the aqueous solution of FM. By doing the calculation in the whole concentration range of the aqueous solution of FM, it was found that FM could strengthen the local structure of water in water-rich region. As the concentration increased, the association of water itself would be replaced by cross-association between water and FM gradually. In the FM-rich region, it was mainly the linear association of FM itself.