Hydration analysis of the adamantane derivatives and water molecules

Abstract

Adamantane has many interesting physical and chemical properties because of the high symmetry. We chose five adamantane derivatives as the model molecule of hydrophobic hydration. The target molecule of simulation is adamantane, 1-adamantyl chloride, 1-adamantyl fluoride, amantadinium cation and perfluoroadamantane. Perfluoroadamantane is adamantane that hydrogen is substituted with fluorine. We simulate the hydration around the solute molecule by molecular mechanics and canonical Monte Carlo method. The water model is TIP3P. The radius of the simulation sphere is about 15.3Å. A solute molecule and 500 water molecules exist in the simulation sphere. We compare the radial distribution functions of water molecules around the solute molecule. In the case of 1-adamantyl chloride, the first peak of the radial distribution is lower than the case of adamantane. In the case of perfluoroadamantane, the first peak is farther and higher than the case of adamantane. The peaks of 1-adamantyl fluoride and amantadinium cation are quite similar to the peak of adamantane.