Calixarene-cupped caesium: a coordination conundrums?
Abstract
Determination of the crystal structure of the mono-caesium derivative of the macrccyclic tetraphenol p-tert-butylcalix[4]arene shows the metal atom to be bound within the cup formed by the ligand; the metal is thereby in much closer proximity to the aromatic carbon atoms than to the phenolic oxygens, indicating that it is involved in polyhapto bonding to a delocalised anionic ligand.