Synthesis Of Lanthanide Phosphonate Complexes Based On 4-(Pyridyl-N-Oxide) Methylphosphonic Acid Ligand And Fluorescence Detection For Fe³⁺,Acetone And Trans,Trans-muconic Acid

In this thesis,4-(pyridyl-N-oxide)methylphosphonic acid ligand was designed and synthesized,and 16 lanthanide phosphonate complexes were prepared by reaction with lanthanide metals,and the single crystal structures were characterized.Studies on the magnetic and optical properties of the complexes show that some of the complexes are fluorescent and magnetic.The use of fluorescent complexes as probes have been used to detect metal ions,small organic molecules and small biological molecules.The main results are as follows:1.The organic phosphonic acid(H₂L)was designed and synthesized,and four series of totally 16 lanthanide phosphonate complexes were synthesized via diffusion and hydrothermal method.The molecular formulas are{[Ln(L)(H₂O)₃]Cl·H₂O}_n[Ln=Eu(1),La(2),Ce(3),Nd(4),Sm(5)];{[Ln₂(L)₂(H₂O)₅]2Cl·2H₂O}_n[Ln=Eu(6),Tb(7),Dy(8)];[Ln(L)(OH)(H₂O)]_n[Ln=Eu(9),Tb(10),Dy(11)];{[Ln₃(HL)₃(L)₃]·3H₂O}_n[Ln=Er(12),Ho(13),Tm(14),Yb(15),Lu(16)].The crystal structures were determined by single-crystal X-ray diffraction(SXRD),powder X-ray diffraction analysis(PXRD),infrared spectrum analysis(IR),thermogravimetric analysis(TGA)and elemental analysis(EA).Optical and magnetic studies of the complexes show that complex 1,6,and 7 show significant photoluminescence.Complexes 7,8,10,and 11 have weak ferromagnetic interactions.2.This thesis focuses on exploring fluorescent complexes as probes for biological detection research:1)Complex 1 has high sensitivity,good selectivity and good reproducibility for the fluorescence detection of acetone and Fe³⁺.Studies on the mechanism of fluorescence quenching indicate that the fluorescence quenching of the analyte and complex 1 is achieved through the energy absorption competition.2)Complex 7 was able to detect acetone and Fe³⁺under simulated body fluid environment with high sensitivity and selectivity.The fluorescence quenching mechanism shows that the fluorescence quenching mechanism of the test object and it is similar to that of complex 1.3)Complex 6 can detect trans,trans-mucoic acid(tt-MA)with high selectivity and sensitivity.Through experiments and density functional theory calculations show that the energy absorption competition between tt-MA and complex 6,the coordination of the central metal and the analyte,and the photoinduced electron transfer are the causes of its the fluorescence quenching.