Solvation structures of the 18-crown-6 in carbon tetrachloride as studied by Monte-Carlo simulation based on ab initio potential models

Solvation structure of the 18-crown-6 molecule in carbon tetrachloride (CCl4) was investigated by Monte-Carlo simulation technique using ab initio pair potential function. The 18-crown-6-CCl4 and the CCl4-CCl4 pair potential functions were constructed from sets of interaction energies computed quantum mechanically at the HF/D95** and MP2/6-31G** levels. The simulation was carried out for a system consisting of 259 CCl4 molecules plus one 18-crown-6 molecule. The simulation results reveal that there are two CCl4 molecules in the first solvation shell; one lies above the ligand plane and other lies below it. The CCl4 molecules prefer to approach closer to the O atoms than the C atoms of the 18-crown-6 molecule. The entire solvation structure around the 18-crown-6 was observed even the 18-crown-6-CCl4 interaction is rather weak.