The Design Of Schiff Base Ligands And The Synthesis And Luminescent Properties Of Lanthanide Complexes

In this thesis,with p-nitrophenol,o-nitrophenol,dibromomethane,1,4-dibromobutane and 1,10-dibromodecane as raw materials,diamines were synthesized firstly by the Williamson and nitro reduction reactions.Then,five new Schiff base ligands were synthesized from the reactions of the diamines with2,3-dihydroxybenzaldehyde and 2-hydroxy-3-methoxybenzaldehyde.These Schiff base ligands have abundant coordination sites with metal ions.The synthesized ligands were characterized by ¹H NMR and ¹³C NMR.Six series of thirteen lanthanide-based complexes were successfully constructed from the reactions of above Schiff base ligands with transition metal salts under refluxing in solution,including two trinuclear Cd₂-Ln-L¹(Ln=Gd(1),Sm(2)),three tetranuclear Zn₂-Ln₂-L²(Ln=Er(3),Dy(4),Ho(5)),one hexanuclear Ni₄-Nd₂-L³(6),two dodecanuclear Cd₈-Ln₄-L³(Ln=Nd(7),Yb(8)),two trinuclear Cd₂-Ln-L⁴(Ln=Nd(9),Ho(10))and three 18-nuclear Ln₁₈-L⁵(Ln=Nd(11),Yb(12),Eu(13))complexes.The crystal structures of these lanthanide-based complexes were determined,and they were characterized by XRD,XRD,SEM,EDX,IR,UV and TG.The luminescence properties of these complexes were studied,and the results show that complexes 7,8,11,12 and 13 show lanthanide luminescence.Meanwhile,for those complexes with strong emissions,their luminescent response behavior to nitro explosive,antibiotics and anthrax metabolite DPA was investigated.The results show that complex7 displays a high luminescence sensitivity to explosive 2,4,6-trinitrophenol(TNP),while complexes 8 and 11 display luminescent response to p-nitrofurans(e.g.,furacilin,furantoin,furazolidone and furanthone).In addition,the 18-nuclear complex 13 can be used as a fluorescent probe for the rapid detection of DPA.Further study shows that the test paper with the Eu₁₈ complex can be used in the visual fluorescence detection of DPA under the UV lamp,indicating its potential application in fluorescence recognition.