Design,Synthesis And Optical Properties Of 1,3-Bis(Arylimino) Isoindoline-4,7-Diols

Disubstituted iminoisoindolines have great potential applications in the fields of macrocyclic compounds,catalytic ligands and dyes,but the synthesis methods of these compounds are complex and limited,which brings serious bottlenecks in the development of their applications.It is particularly important to develop a novel method for the synthesis of these compounds.In this paper,a new copper-catalyzed reaction of o-phthalonitrile with amines to produce 1,3-bis?substitutedimino?isoindolines were investigated.This method is one-step synthesis with high yield and accords with the principles of atomic economy and green chemistry.This paper is mainly divided into three parts:the discussion of reaction conditions,the discussion of reaction applicability and the expansion of application.In chapter 1,the practical applications of 1,3-diiminoisoindoline?including macrocyclic compounds,catalytic ligands and dyes?,the synthesis of 1,3-bis?alkyl/arylimino?isoindoline and the research progress of organic fluorescent small molecule probes(including fluorescence probe mechanism,p H fluorescence probe and Zn²⁺fluorescence probe)are introduced.At the same time,the research content and innovation of this paper are put forward.In chapter 2,a new method for the synthesis of 1,3-bis?arylimino?isoindoline-4,7-diols were designed.This new synthesis method is one-step synthesis with high yield and accords with the principles of atomic economy and green chemistry.Through the method of controlled variables,the optimum reaction conditions for the direct synthesis of 1,3-bis?arylimino?isoindoline-4,7-diols were successfully explored:Under the protection of nitrogen,the mixture of2,3-dicyanohydroquinone?0.5 mmol?and aniline?2.5 mmol?in ethylene glycol?4 m L?,and then added Cu Br₂?15 mol%?was reacted for 15 h in an oil bath at a temperature of 120 ^oC.After crude production is precipitated in the aqueous phase to remove impurities,a high yield of 92%can be obtained.In chapter 3,we explore the compatibility of the synthesis of 1,3-bis?arylimino?isoindoline-4,7-diols.Based on the optimum reaction conditions explored in the second chapter,13 products of 1,3-bis?arylimino?isoindoline-4,7-diols and 2,3-bis?1H-benzo[d]imidazol-2-yl?benzene-1,4-diol were successfully synthesized by using the derivatives of 2,3-dicyanohydroquinone and aniline,including 13 new compounds.Among them,the product substituted by the electron donor-group can reach a high yield of about 90%,and the product substituted by the weak electron-withdrawing group can reach a medium yield of 50%,but the product substituted by the strong electron-withdrawing group can't be synthesized.At the same time,we proposed a possible reaction mechanism.In chapter 4,the fluorescence properties of some of the compounds synthesized in this paper were determined,and they have strong fluorescence properties.At the same time,the law of their optical properties were explored,and a proton transfer dye molecule?1,3-bis?2-methoxyphenylimino?isoindoline-4,7-diol?and p H fluorescence probe molecule?1,3-bis?4-hydroxyphenylimino?isoindoline-4,7-diphenol?were found.1,3-bis?2-methoxy phenylimino?isoindoline-4,7-diol is a new type of proton dye molecule,which appears red in proton solvents and yellow in other solvents.The fluorescence intensity of 1,3-bis?4-hydroxyphenylimino?isoindoline-4,7-diphenol is very weak under neutral condition,and the fluorescence intensity increases with the increase of p H value.The p Ka value of1,3-bis?4-hydroxyphenylimino?isoindoline-4,7-diphenol is p K_a=7.91±0.04,and its fluorescence intensity at 607 nm has a good linear relationship with its corresponding p H value when the p H value is in the range of 7.00 to 9.30.This property can be applied in p H fluorescence probe.The fifth chapter summarizes the research results of this paper,and introduces the future development direction of this research.