Molecular dynamics simulations of 18-crown-6 aqueous solutions

Physicochemical, thermodynamic and structural properties of 18-crown-6 aqueous solutions were investigated by molecular dynamics simulations. Force fields for flexible solute and solvent molecules were used. The calculated values of the density, hydration enthalpy, self-diffusion coefficients and their concentration dependences were found to be close to experimental data. The structure of hydration shells of crown ether molecules and the structure of water in the solutions were determined. A residence lifetime distribution of water molecules from the first hydration shell of a crown ether molecule shows a presence of long-lived states with typical lifetimes of hundreds picoseconds.