Solid-state assembly of oxyfunctionalized calix[4]arene derivatives

The solid-state assembly of four calix[4]arene derivatives bearing one or two rings oxyfunctionalized with epoxy and hydroxyl functional groups has been structurally studied by X-ray crystallography. In three cases the presence of OH groups pointing towards the exterior of the molecule allows the formation of intermolecular OH center dot center dot center dot epoxy H-bonds, which give rise to columnar structures, with zigzag or parallel oriented molecules, or helical arrangement of quadruplex elements. In one instance, in the absence of intermolecular H-bonds, columnar stacks of molecules are obtained mainly through intermolecular van der Waals interactions.