The Role Of Hydrogen-bond Interaction On Host-guest Behaviors Of Pillar[5]arene

Supramolecular chemistry is one of the most important and attractive fields in chemistry.The discovery of any new class of macrocycles can accelerate the development of supramolecular chemistry.Pillar[n]arene is a new type of calixarene analogue made up of hydroquinone units that are linked by methylene(-CH2-)bridges.Since first discovered in 2008,pillar[n]arenes have attracted many attention because of their extensive applications in molecular recognition and supramolecular self-assembly.Many pillar[n]arene derivatives were synthesized and their binding behaviors with some typical guests were investigated.The construction of several of molecular aggregates based on pillar[n]arene derivatives were also studied.In the present paper,we synthesized some pillar[5]arene derivatives containing adenine substituents.Guest molecules containing pyrimidine bases also were synthesized.We demonstrated that a mono-adenine functionalized pillar[5]arene and a linear guest assembled into a novel fourunit [c2]daisy chian.This [c2]daisy chain does not contain a linear thread bound with the host by covalent bonds,in contrast to [c2]daisy chains reported previously.The present research reveals that monomers without a linear thread could form a daisy chain and provides a new approach for the construction of mechanically interlocked molecules.Work on traditional mechanically interlocked molecules can probably be extended to this new type,and allow for the construction of ‘‘smart'' supramolecular materials.In addition,effects of hydrogen-bond interactions on the binding behaviors of pillar[n]arene hosts and some guests containing pyrimidine were also discussed.