Monte Carlo simulation of a cyclen molecule in water

Abstract

A Monte Carlo simulation has been carried out for a 1,4,7,10-tetra-azacyclododecane (cyclen) molecule in water at 25 °C and 1 atm. The cyclen–water potential function was derived from ab initio calculations, while for the water–water interaction the MCY (Matsuoka–Clementi–Yoshimine) potential was used. The results of the calculations have been analysed with respect to water binding centres of the molecule, radial distribution functions in various directions and distribution of coordination numbers. Two water molecules are oriented towards the molecule's centre (above and below the ligand plane) and a further 11–12 water molecules are located in a sphere of 4–6 Å around the ligand. Structural influence on the solvent is observed up to 8–9 Å from the molecular centre. The results of this study supply for the first time detailed information about the surrounding solvent structure and group solvation numbers of a macrocyclic ligand.