Hydrogen-bonded molecular capsules: probing the role of water molecules in capsule formation in modified cyclotricatechylene

Abstract

Two new pyridine moiety-appended cavitands, CTC(Py)₂(OH)₂ and CTC(Py)₃, were synthesized and characterized. The solid state structures of both cavitands were studied by single crystal X-ray diffraction. CTC(Py)₂(OH)₂ resulted in a hydrogen-bonded dimeric molecular capsule, entrapping two molecules of DMSO and intervening water molecules that formed hydrogen bonding to DMSO and CTC(Py)₂(OH)₂. When crystallized in the absence of water, it forms a 2D polymer by hydrogen bonding of pyridine nitrogen and phenolic hydrogen atoms. CTC(Py)₃ forms no such capsule.