Molecular dynamics simulation of ion binding in aqueous solution of 18-crown-6 ether

Crown ethers are unique compounds with exceptional ion binding properties. We investigate the 18-crown-6 ether molecule binding selectivity for a set of alkali ions (K⁺, Rb⁺, Cs⁺). We employ combination of umbrella sampling technique with the weighted histogram analysis method to derive free energies of ion–ether association. The obtained results are in a good agreement with experimental values available and represent the ion selectivity feature of the 18-crown-6 ether.