Pentacyclic Nano-Trefoil

Tetra-armed cyclen (1) bearing two 4-(4'-pyridyl)benzyl and two 3,5-difluorobenzyl groups and its Ag+ complexes were prepared and structurally characterized. The complexes formed between 1 and Ag+ undergoes a reversible structural transformation between a 2:2 dimeric complex and a 3:5 pentacyclic trefoil complex with changes in the Ag+/ 1 molar ratio. It was also revealed that the 3:5 trefoil complex could encapsulate benzene and [D6]benzene selectively in solid-state. The benzene-included structures are stabilized by C-H center dot center dot center dot F-C interactions between the benzene molecule and the ligand molecule.