Synthesis And Host-Guest Recognitions Properties Studies Of Functionalized Pillar[n]arenes

Supramolecular chemistry is a raising interdisciplinary discipline that focuses on molecules assembling,mostly via noncovalent interactions,into complex and ordered molecular aggregates with specific functions.Since Pedersen,Cram and Lehn won the Nobel Prize in Chemistry in 1987,supramolecular chemistry has attracted more generous attention and indepth research.One of the most important aspects in supramolecular chemistry is the host–guest interaction based on macrocyclic molecules including crown ethers,cyclodextrins,calixarenes and cucurbiturils.The majority of studies on macrocyclic hosts are focused on host–guest interactions and their applications.However,pillar[n]arenes?n=5-15?are a novel class of macrocyclic molecules with hydroquinone as the repeating unit linked by methylene bridges at para-positions.Introduced by T.Ogoshi for the first time in 2008,pillararenes have attracted increasing interest and have been widely studied during the last nine years,due to their unique structural advantages as host molecules,such as symmetrical rigid architecture,electron-rich cavities and facile functional modification.In this dissertation,we introduced the synthesis of pillararenes and summarized the host-guest properties,a summary of the different kinds of guest motifs,summarising almost numerous different kinds of guest motifs and dividing them into three types:cationic,neutral and anionic motifs.The main section of this dissertation examines the applications of pillar[n]arenes based on the host–guest interactions in different research fields.In the first part,we are summarizing related studies and providing a overview of pillararene chemistry.We describe strategies for the synthesis and functionalization of pillararenes.Meanwhile,we will highlight their applications based on host–guest interactions,as well as their potential in the future.The contents of this part include the syntheses of pillar[n]arenes and functionalization,a summary of the different kinds of guest motifs,the applications of host–guest interactions in the different research fields of biology,materials science and environmental science,and their future outlook.In the second part,we have designed and synthesised a novel copillar[5]arene-based chemosensor,which employ 8-hydroxyquinoline group as a binding site and signal group.By a novel cyanide-induced self-assemble mechanism,the pillar[5]arene-based chemosensor shown high sensitivity and selectivity for cyanide in aqueous media.Moreover,test strips based on the sensor were fabricated,the chemosensor is a good cyaniade test kits.In addition,we made life applications of cyanide detected,the chemosensor is also could detect cyanide in aqueous extracts from sprouting potatoes.It is worth mentioning that cyanide-induced self-assemble mechanism is a novel strategy for the design of pillararene based chemosensor.In the third part,we designed and synthesised a novel copillar[5]arene PF5,which can be self-inclusion produce a strong blue fluorescence.Pillar[5]arene-based chemosensor PF5 could be a sequential fluorescence sensor for ferric ions???followed by fluoride ions with high sensitivity and selectivity in aqueous solution.Moreover,test strips based on the sensor were fabricated,which could be very good sequential test kits for ferric ions???and fluoride ions.Moreover,the sensor PF5 could also sequential detect Fe³⁺in tap water and F^-in toothpastes.In the fourth part,a host-guest system was successfully constructed from a host molecule,DMpillar[5]arene?DMP5?,and six guest molecules,a series of benzazole compounds,vis host-guest interactions and characterized using a combination of various techniques;including HRMS,¹H-NMR,and 2D NMR NOESY ¹H-¹H spectroscopy.The host-guest system was constructed by DMpillar[5]arene and benzazole via heterocyclic compound threaded in the cavity of pillar[5]arene formed sandwich-type structural.Interestingly,the corresponding guest containing benzazole formed a stable host-guest complex with the same host.In addition,the addition of guest compounds led to the effective renforcement of the fluorescence intensity compared with the original guest species and the host?DMP5?,giving additional support for the host–guest interaction based supramolecular assembly nature of the present system.