A study on the inclusion phenomena occuring between crown ethers and alkaline metal cations using Monte Carlo simulations

Abstract

Monte Carlo simulations for the 12-crown-4 plus Li⁺ system in dimethyl ether were carried out. The distances between the Li⁺ and the center of the four oxygen atoms in 12-crown-4 were set to 0.05, 0.45 or 0.85 nm. In order to express the densities and the orientations of the solvent molecules, a widely utilizable color graphic interface program, GRICE (GRaphic Interface for Computer Experiments), was developed. The figures indicate that the solvation sphere is more widely extended in the case of x = 0.85 nm than in the case of x =0.05 nm. Hence, the solvent-solvent interaction energy in the case of x =0.85 nm was thought to be more unstable than in the case of x = 0.05 and 0.45 nm. The calculated results on the components of the interaction energies agreed with the above-mentioned estimation. Thus, the driving force of the inclusion phenomena occuring between crown ethers and alkaline metal cations was suggested to be variation of solvent-solvent interactions.