Synthesis,Spectral Properties And Density Functional Theory(DFT) Of 1,8-naphthyridine Derivatives

1,8-naphthyridine derivatives is a class of organic compounds with good photochemical properties,excellent coordination ability with various transition metals and various specific biological activities.They are widely used in organic synthesis,new chemical materials,biomedical and other fields.Based on this,eight1,8-naphthyridine derivatives and one 2,6-diaminopyridine derivative compound were designed and characterized.Their structures were confirmed by NMR,MS,IR.Their spectral properties and ion recognition performance were characterized by ultraviolet and fluorescence.The theoretical study for the eight naphthyridine compounds were investigated by using Density Functional Theory（DFT）.The paper has made some meaningful results.The main results are as follows:1.1,8-naphthyridine compounds were synthesized and their structures of the compounds were characterized.Their photochemical properties in different solvents were determined and their ion recognition performance was researched.The results show that L1,L2,L3,L5,L7 of the eight compounds synthesized can coordinate with more than two kinds of metal ions,and their corresponding coordination compounds will be synthesized later.2.As cationic fluorescent probes,L4 and L8 can recognize Fe³⁺,specifically.Their concentration limit of detection,complexation constants were detected.Compared with L4,the schiff base L8 has good effect for Fe³⁺and can be recognized by naked eyes,and the latter may be used in imaging nematodes.It is possible to use it as a chemical fluorescent probe to track the metabolism of iron to determe if iron is in excess or not,which is helpful for people to effectively prevent various diseases caused by iron metabolism disorders.3.Pb²⁺can be recognized by L6,specifically.The detection limits for concentration,complexation constants and on which some ions impact explored by concentration titration for L6.The latter may be used in nematode imagination.It is expected to be used as a fluorescent probe to detect the concentration of lead ions for avoiding heavy metal pollution.High lead ion concentration will harm human hematopoietic system,and lead to human disease by damaging function of systemic and renal.4.The 2,6-diaminopyridine compound was synthesized and characterized compounds.It’s photochemical properties in different solvents were determined and performance in ion recognition was researched.5.It was investicated for the eight 1,8-naphthyridine derivatives.Their frontier orbitals and energy gaps,electron absorption spectra and the molecular structures were researched by using Density Functional Theory（DFT）,and their absorption peaks were characterized and attributed.