Design,Synthesis And Photo-Thermal Response Of Donor-Acceptor Stenhouse Adducts Based On Aliphatic Amine Donor

Organic photochromic molecules have developed rapidly in recent decades.Because of their great potential in the fields of drug delivery,biological regulation,and information storage and encryption,this type of molecule has become a research hotspot today.In recent years,a new type of photochromic molecule called Stenhouse Donor-Acceptor Stenhouse Adducts（DASA）has entered the field of view of researchers in the field of photochromic research.Light-excited photochromic molecules can change from dark to light,from a hydrophobic structure to a hydrophilic structure,from a linear configuration to a cyclic configuration,and have obvious colors under the irradiation of visible light.Changes and good fatigue resistance enhance its application capabilities.This article will conduct research from the following five chapters:The first chapter introduces the basic concepts,classification and application prospects of photochromic compounds,and also introduces the knowledge background of DASAs compounds.In Chapters 2,3 and 4,we designed and synthesized three DASAs molecules based on fatty amine donors（compounds 1,2,and 3）.Through ¹H NMR,¹³C NMR,¹H-¹H COSY,HSQC,HRMS,IR and other characterization methods,it is clear that DASAs molecules can be opened with purple/red triene conjugated ring structure（a）,yellow/colorless cyclopentene,respectively Three isomers of ketone single closed ring（b）or cyclopentanone double closed ring structure（c）are the main existing forms.In particular,compound 1 obtained the three isomers a,b,and c of DASAs simultaneously under different synthetic conditions for the first time.We first studied that the ring-opening isomer a of compound 1 undergoes isomerization under the stimulation of visible light,transforms to the single-ring-closed isomer b,and then reversibly recovers by thermal relaxation.Different from the single light response behavior reported in the literature,the DASAs molecules in this paper can also respond to various stimuli such as acid-base and temperature changes and exhibit complex isomerization behaviors.In the DMSO solution of the ring-opening isomer a of compounds 1 and 3,it was found to have a reversible acid-base stimulation response.In response to acid-base stimulation,we detected three new isomers（α,β,γ）by NMR and speculated that the structural form described in the text exists.Not only that,we also conducted a qualitative study on the low temperature stimulus response of compounds 1-3,which showed interesting color changes.By changing the structure of the donor or acceptor of DASA,we compared the responsiveness of these three DASAs to different stimulus conditions,showing that changes in the groups of the donor and acceptor can effectively regulate the relative stability of the isomers,thereby regulate the isomerization behavior of DASAs.The fifth chapter will briefly summarize the work done in this thesis and look forward to the future work.