| The special electronic configuration of lanthanide elements makes it unique in magnetic,optical sensing,biological activity,and catalysis.Therefore,the research on the directional construction,assembly process tracking and function regulation of multifunctional lanthanide complexes is of great significance.The synthesis of lanthanide metal complexes usually involves a variety of influencing factors and assembly methods,so choosing an appropriate method to track the assembly process and suggesting that the assembly mechanism is the basis for the design and synthesis of cluster compounds.In this thesis,mononuclear Ni?L?2 with o-vanillin Schiff base and salicylaldehyde Schiff base as ligands,and lanthanide ions as induced ions,successfully constructed a series of multifunctional lanthanide complexes and 3d-4f metal complex.We have performed magnetic and fluorescence sensing studies on the above lanthanide complexes,and track the solid-liquid relationship and assembly process of these complexes by combining crystallography and electrospray ionization mass spectrometry?ESI-MS?.And try to propose its assembly mechanism.The full text is divided into five chapters:The first chapter is the foreword,which introduces the significance of this topic and the research background of related fields.It focuses on the experimental examples and latest research progress of multifunctional lanthanide complexes and multifunctional 3d-4f heterometallic complexes.This paper introduces the research and application of electrospray ionization mass spectrometry?ESI-MS?in cluster assembly and decomposition process,and provides new ideas and strategies for the synthesis of lanthanide complexes.The second chapter,four complexes,[Ln2?L2?2?NO3?4]·2CH3OH?Ln=Tb?1?,Dy?2?,Ho?3?,Er?4?,and L2=?E?-2methoxy-6-???pyridin-2-ylmethyl?imino?methyl?phenol?,were obtained by reacting?E?-2-??3-methoxy2-oxidobenzylidene?amino?ethanesulfonate?L1?,Ln?NO3?3·6H2O,and2-aminomethylpyridine at room temperature under solvothermal conditions in methanol for 12 h.The new Schiff base L2 was generated in situ based on the organic ligand L1 and2-aminomethylpyridine through Schiff base exchange reaction by using lanthanide salts as inductor.A combination of crystallography and mass spectrometry was performed to track the exchange reaction,and the underlying mechanism accompanied by the complex assembly process was clearly presented.the multistep formation mechanism of the above dinuclear complex was also proposed,i.e.,[L1]?Dy[L1]/[L2]?Dy[L2]?Dy[L2]2?Dy2[L2]2.Luminescence test of 1 showed that it had extremely high selectivity to dichloromethane?CH2Cl2?.Therefore,we established a quick,simple,and efficient method of detecting CH2Cl2that enabled strong-luminescence observation with the naked eye.tests for small amounts of CH2Cl2 in water further indicated the potential of 1 as a test strip for CH2Cl2 fluorescence detection in water samples.Alternating-current magnetic susceptibility studies indicated the field-induced single-molecule magnet behavior of 2.The third chapter,planar mononuclear Ni?L1?2?L1=2-ethoxy-6-?iminomethyl?phenol?was dissolved in methanol and added with Dy?NO3?3·6H2O for 48 h at room temperature to obtain a butterfly-like Ni2Dy2 cluster?[Dy2Ni2?L1?4?CH3O?2?NO3?4],5?.The Dy?III?ions in cluster 5 were in the O8N coordination environment,and the Ni?II?ions were in the O5N coordination environment.High-resolution electrospray mass spectrometry?HRESI-MS?was used to track species changes during the formation of cluster 5.Six key intermediate fragments were screened,and the self-assembly mechanism was proposed as Ni?L1?2?HL1+Ni L1?DyL1/Ni?L1?2'?DyNi?L1?2?Dy2Ni2?L1?4.Through this assembly mechanism,we found that Ni?L1?2 first cleaved into HL1+NiL1 and then further assembled to obtain 5.Another butterfly-like tetranuclear heterometallic cluster?[Dy2Ni2?L2?4?CH3O?2?NO3?4],6?was obtained using planar mononuclear Ni?L2?2?L2=?E?-2-ethoxy-6-??methylimino?methyl?phenol?with-CH3 substitution on the nitrogen atom under the same reaction conditions.The structural analysis of cluster 6 showed that the Dy?III?ions were in the O9 coordination environment,and the Ni?II?ions were in the O4N2 coordination environment.HRESI-MS was used to trace species change during the formation of 6,and the assembly mechanism was proposed as Ni?L2?2?DyNi?L2?2?Dy2Ni?L2?2?Dy2Ni2?L2?4.Analysis of the assembly mechanism of 6 showed that Ni?L2?2 was twisted during the reaction,and its coordination point was exposed to capture the Dy?III?ions.Finally,Dy?NO3?3·6H2O was replaced with NaN3 to obtain cluster[Ni2Na2?L2?4?N3?4]?7?under the same reaction conditions and verify the above-mentioned torsion step.HRESI-MS was also used to trace the assembly process,and the assembly mechanism was proposed as Ni?L2?2?NiNa?L2?2?NiNa2?L2?2?Ni2Na2?L2?4.Herein,the substitution effect interference and regulation self-assembly process were discovered in the formation of 3d-4f heterometallic clusters and different types of coordination clusters were obtained.The four chapter,under solvothermal conditions,we synthesized HLc??E?-1-???1-methyl-1H-benzo[d]imidazol-2-yl?methylene?amino?naphthalen-2-ol?by in situ reaction with 1-methyl-1H-benzo[d]imidazole-2-carbaldehyde?La?and 1-aminonaphthalen-2-ol?Lb?,and then added Ln?III?to gradually assemble to form four cases of binuclear lanthanide complexes Ln2?Ln=Dy?8?,Tb?9?,Ho?10?and Er?11??.Combining crystallography and ESI-MS to track the assembly process of the above-mentioned dinuclear complexes,and proposed its assembly mechanism:La+Lb?HLc?Ln1?Ln2.Magnetic studies show that complex 8 behaves as a single-molecule magnet under zero magnetic field.Finally,the work of the whole paper is briefly summarized. |
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