Influence Of Different Factors On The Dynamic Mechanism Of Excited Hydrogen Bond

Weller et al.are the first to observe the phenomenon of excited intramolecular proton transfer(ESIPT)in salicylic acid molecules.So far,related research has attracted wide attention from scientists.With the development of science and technology,the scope of research has become more and more extensive.A large number of theoretical and experimental studies have revealed that the presence of a plurality of hydrogen bonds in the molecule,which is ESIPT reaction process more complex.If the substituents and benzene rings number is changed in the molecule,a new ESIPT reaction mechanism may be derived.In the first chapters,the introduction briefly introduces the development history of photochemical reactions,as well as the theoretical knowledge about hydrogen bonds,excited states and proton transfer reactions.The second chapter mainly introduces the development process of quantum chemistry theoretical calculation methods,and expresses in detail the problems and solutions encountered in each development stage.The last subsection of second chapters introduces the relevant expressions of the RDG isosurface.In the third chapters,we discussed the theoretical study of the intramolecular proton transfer in the excited state of the BTS molecule,and proved that the hydrogen bond interaction mechanism has been enhanced from many aspects.Because BTS molecules have two intramolecular hydrogen bonds,it is not clear whether the excited state intramolecular proton transfer reaction is a coordinated reaction or a stepwise reaction.For this reason,the stepwise reaction sequence of BTS molecules determined by scanning the potential energy surface and the potential energy curve is BTS?BTS-A?BTS-D.In the fourth chapters,the influence of substituent effects on the excited state intramolecular proton transfer of 2-aryloxazoline derivatives is mainly analyzed.In this chapter,we have selected five representative molecular structures in the experimental articles.2u and 2ad have different substituents;2ad?2ai and 2ah have different benzene rings number.The first four summaries confirm the enhancement mechanism of hydrogen bond interaction from different aspects.In the first four junctions,the hydrogen bond interaction enhancement mechanism was confirmed from different aspects.Through the analysis of the potential energy curve of the fifth junction,two conclusions can be drawn: 1.When the substituents are different,the potential barriers that the excited state proton transfer reaction needs to cross are also different.2.As the number of benzene rings increases,the proton transfer reaction is more difficult,and the degree of difficulty is 2af?2ah?2ai.The five chapters summarize the whole paper.The last section is the acknowledgment part.