Design,Synthesis And Properties Of Metastable-State Photoacids And Their Applications In Black Printing Of Rewritable Paper

Photoacids,as a class of molecules whose acidity could be controlled by light,have a great application prospect in numerous chemical reactions,biological functions,and material properties.Among them,the proton transfer process can be remotely,temporally and spatially controlled with light using different types of photoacids,such as photoacid generators and excited state photoacids.However,they have the disadvantage of irreversible processes or short lifetime of the proton dissociation state,which hinders them from widespread applications.Liao's group recently reported a metastable-state photoacid can produce a large proton concentration with high efficiency and good reversibility.In addition,it has a long lifetime of proton-dissociation state.Given these excellent performance,this metastable-state photoacid has attracted considerable attentions and been utilized in control of acid-catalyzed reactions,supramolecular assemblies,microbial fuel cells,bacteria killing,cationic sensors,odorant release and so on.Yet,substituent effect on the metastable-state photoacid has not been studied systematically.As we all known,substituents have great influence on photochemical properties of molecules,which will further affect their applications.Therefore,it's necessary to study the effect of substituents on the properties of this central concerned metastable-state photoacid both from the perspectives of foundament research and practical application.In the second chapter,we designed and synthesized sixteen metastable-state photoacid derivatives containing various substituents at different position of the molecular skeleton,and systematically investigated the effect of introduced substituents on their photochemical properties.Several important nature of the photoacids,such as displaying color,solubility,molar absorption coefficient,pK_a,dark-acidity,photosensitivity,photoacidity,relaxation kinetic,were demonstrated closely related to their connected functional groups.This study will be conducive to targetedly design and synthesize promising photoacids as well as to apply their photo-controlled proton-release processes in functional materials or devices.In the third chapter,based on our previously prepared visible-light-response rewritable paper,I have mainly explored the black printing aspect systematically.At the first stage,we studied two-component black printing system for the rewritable paper based on photoacid and ODB-2 in detail.Later,we improved the color-layer with complementary colors.Thus a three-component black printing system,including F-P,ODB-2 and MO,was formed.And finally the visible-light-response rewritable paper containing a three-layer structure was prepared and achieved high blackness,excellent print resolution,and rewritable performance.