Molecular dynamics study of p-tert-butylcalix[4]arenetetraamide and its complexes with neutral and cationic guests. Influence of solvation on structures and stabilities

A series of molecular dynamics simulations have been performed on tert-butylcalix[4]arenetetraamide ligand L, with neutral or anionic guests inside the cone (MeOH, MeCN, H 2 O, SCN - ) or with cations (Li + -Cs + , Eu 3+ ) in the pseudocavity at the lower rim. The uncomplexed ligand L is found to be not preorganized in vacuo or in water to complex cations at the lower rim. The structure and dynamics of LM n+ complexes differ from the solid-state picture of the LK + complex. They depend on the size and charge of the cation and on solvation effects