The Reduction Behavior Of Perylene Diimide Carboxylic Acid Derivatives Interacts With The Host And Guest

Aromatic diimides have attracted much attention because of their modifiable structure,strong electron affinity and excellent optoelectronic properties.As a group of aromatic diimides,perylene bisimides(PBI)have aroused considerable interest during the last few decades due to their unique characteristics,such as high fluorescence quantum yield,outstanding photochemical stability and unambiguous behavior in self-assembly.Therefore,they have found extensive applications in many fields,including organic electronics,fluorescence sensors and bio-probes,etc.Because their structure combines two sets of six-membered electron-withdrawing dicarboxylic imide rings and the π-conjugate structure,perylene bisimides exhibit high electron affinity,which endows PBI with the ability to gain electrons resulting in the formation of reductive species including radical anions and dianions.In fact,these reductive species have been used for photo-catalysis,scavenging of oxygen-related oxidative species,creation of photothermal conversion materials,etc.Though PBI,PBI-· and PBI2-are structurally similar,they are different in their electronic structures.Thus,their relative concentrations would have significant effects on the collective properties and potential applications of the system,implying the importance of tuning the composition of PBI-containing systems.However,to the best of our knowledge,no effort has been made in this regard.Supramolecular chemistry,which exploits the reversible nature of noncovalent interactions,has proved especially useful in the constructions of self-assembled responsive materials.Host-guest chemistry based upon the macrocyclic compound,plays a pivotal role in the supramolecular chemistry.Due to their large cavity volume,macrocyclic compounds,such as crown ethers,cyclodextrins(CD),and cucurbiturils(CB),have found extensive applications in the fields of drug release,catalysis,and opoelectronic devices.As a new type of macrocyclic compounds,calix[4]pyrrole has attracted considerable interest due to its unique characteristics,such as abundant conformations,modifiable structure,and targeted recognition.To verify if supramolecular complex formation could be as a general method to tune the composition of the relative species of an aromatic diimide system,calix[4]pyrrole was introduced into the system.Hence,a calix[4]pyrrole derivative(D-CP)was synthesized as a host,and carboxyl modified perylene/naphthalene bisimides derivatives were synthesized as a guest to construct supramolecular systerms.We not only studied the reductive species formation of PBI derivaties with a supramolecular strategy of host-guest interaction,but also proved that the formation of reductive species was closely related to its aggregation matter via the method of chemical modification.Moreover,a fluorescent supramolecular ensemble was constructed via introducing calix[4]pyrrole into an insoluble NDI system,which could enhance the fluorescence of the system by the disaggregation of the NDI.The dissertation mainly consists of the following two sections.In the first section,a PBI derivative(PDA)and a calix[4]pyrrole derivative were synthesized to construct a supramolecular complex though the host-guest interaction.Specifically,the formation efficiency of the radical anion of PDA was highly enhanced.Importantly,the radical anion of the PDA/D-CP ensemble was more reactive than that of PDA itself.The reason for this was attributed to the enhanced solubility of PDA owing to screening of its aggregation.Inspired by this discovery,chemical modification was employed to tune the reductive species formation of PBI derivatives.It was found that introduction of bulky substitutes at the bay position of a PBI derivative is an effective way to enhance the reduction of the compound.In particular,some of the PBI derivatives could exist mainly in radical anion forms without the need of a base provided DMF.We believe that as developed strategies for tuning the composition of reductive species of PBI derivatives would extend their applications.In the second section,a terminal carbonyl modified NDI derivatives(NDA)was designed and synthesized.Under the control of an organic base,a fluorescent supramolecular ensemble was constructed via the host-guest interaction between the deprotonated NDA and calix[4]pyrrole derivatives(D-CP).Because of the bulky structure of D-CP,formation of the supramolecular complex might suppress the aggregation of NDA,resulting in enhancement the solubility of NDA.1H NMR and FT-IR studies revealed that the formation of the supramolecular complex.Meanwhile,it was found that the complex of NDA/D-CP/DBU displayed short rod and fiber structure though self-assembly in the solvents of ethanol and THF,respectively.In addition,a preliminary test confirmed that the film showed a clear response to aniline vapor,which would facilitate its application.We believe that the results provide a new strategy for the sensing film preparation with NDI as a sensing unit.