Study On The Synthesis, Chromism And Luminescent Of Symmetrical And Asymmetric Substituted Viologens

Viologen is the term of describing N,N'-disubstituted 4,4'-bipyridyl salts.Methyl viologen always been known as the herbicide “paraquat”,is the most commonly known viologen.Viologens possess distinct electron-accepting property and their three redox states are interconvertible.The reversible redox reaction occurred under thermal,optical or electrical stimuli accompany with color-change.Owing to these characters,viologens are potentially useful in the study of chromogenic materials as well as supramolecular chemistry and organic batteries.However,the stability of viologen radical cations is concern in application.In addition,there are a few studies on the properties particular the luminescence of viologens themselves,but focus on the metal-organic frameworks,coordination polymers or super-molecular contain viologens.Hence,we synthesized six case of acetophenone derivatives symmetrical and asymmetric substituted viologen commands based on 4,4'-bipyridy,and researched of the synthesized viologens both in solution and solid states by UV-visible absorption spectroscopy,EPR spectroscopy and other methods.In chapter one,we gave a review of viologens about their discovery,structure features,properties and synthetic methods,summed up the hot research fields in recent years.In chapter two,six viologens were synthesized by two different synthetic methods of symmetrical and asymmetric substituted viologens.IR spectroscopy,NMR spectroscopy are used to characterize and analyze the final product.In chapter three,the chromism and luminescent reaction of viologens in solution was studied.There is a great difference between symmetrical and asymmetric substituted viologens in solution.According to UV-Vis spectra,all theviologens can be colored in NaOH solutions.Based on this,VioCl1 and VioCl2 were used to detection of arginine.The fourth chapter mainly focuses on the photochromism of symmetry substituted viologens as well as mechanochromism and luminescence of asymmetry substituted viologens.The excellent solid-state fluorescence and anion-controlled luminescence performance of asymmetry substituted viologens was discussed and analyzed by fluorescence spectrophotometer and so on.The test paper and functional films with color-changing and luminescence were prepared.