X-Ray Crystal Structures and Molecular Modeling Studies of Calix[4]dibenzocrown-6 and Their Alkali Metal Cation Complexes

We present X-ray structures of complexes of KClO(4). H(2)O and CsPic . H(2)O with a new calix[4]arene bearing a dibenzocrown-6 ether bridge. Alkali metal cation complexes with this macrocycle have been studied by molecular dynamics simulations in vacuo, taking account of the counterion, and in an explicit water phase, in order to compare the computed structures to those determined by X-ray crystallography. Two different sets of atomic charges were used in order to evaluate the influence of the electrostatic representation on the computed structures. The results obtained show that MNDO scaled charges give simulation results in better agreement with the available experimental data than MNDO/ESP.