Supramolecular Networks Constructed By Orthogonal Pillar[5]arene-based Hosts:Applications In Lightharvesting Materials

Since it was first discovered in 2008,pillar[n]arenes are a promising group of macrocylic host.Due to easily to functionalization,highly symmetry structure and excellent host-guest interaction ability,it is widely used in gas adsorption and storage,drug delivery,polymer assembly and photoluminescence and so on.In this paper,a new type of pillar[5]arene was prepared which forms supramolecular polymer with guests under the host-guest interaction,and applied in light-harvesting materials.In addition,pillar[5]arenes were further functionalized,and used to prepare covalent organic framework materials with the dynamic reversible Schiff base reaction.(1)Efficient artificial light-harvesting systems(ALHSs)require excellent capabilities in both harvesting light and transferring energy.In this work,a novel strategy to build ALHSs with ultra-high antenna effect(as high as 32.7)has been developed.The ALHSs were fabricated by a conjugated orthogonal supramolecular networks(COSN),a cross-linked network selfassembly of a tetratopic orthogonal pillar[5]arene-beased host(H)and ditopic guests(Gs).Both the host H and the guests Gs have conjugated rigid structures.It is just the rigid structure that plays the role of scaffold in the COSN,and makes the COSN arrange much more tightly and regularly.Coupled with the “molecular wire” effect of the conjugated structure in the COSN system,the high energy transfer capacity between the donors and the acceptors,and the aggregation-induced emission(AIE)effect of the COSN,the COSN shows an excellent performance.(2)At present,the methods of preparing covalent organic frameworks(COFs)are mainly connecting building units with different geometric configurations in a certain way,so as to realize the pore size inside the material.If the supramolecular macrocycles such as pillararene which possess a prefabricated ‘hole' of a certain type can be introduced into COFs,the materials will have the inherent cavity structure as well as the holes formed by connecting building units,which can further improve the performance of the materials.In this work,we tried to introduce the pillararene into COFs using the Schiff base dehydration reaction,it is expected that the prepared materials have good internal order,permanent porosity and dual-size pore,and good applications in gas adsorption,separation,detection and so on.