Synthesis Of Bis(Salamo)-Type Small Molecule Fluorescence Sensors And Photophysical Properties Of Their Transition Metal Complexes

Salamo-type compound is a multidentate chelate ligand containing N₂O₂ coordination cavity,the N₂O₂ cavity of Salamo-type ligand can coordinates with transition metal ions or atoms to form tetradentate chelated mononuclear complexes.Of course,two or more Salamo-type compounds may also form dinuclear,trinuclear or even multinuclear metal complexes with multiple transition metals or rare earth elements.In these complexes,metal atoms or ions are generally bridged by phenolic oxygen atoms in the ligands.In addition,solvent molecules participate in coordination complexes may also contribute to the assembly of complexes.In view of these characteristics,Salamo-type complexes have important applications in the fields of supramolecular chemistry,stereochemistry,catalysis,and magnetism.In addition,as chemical trace detection and control formation techniques are being used more and more widely,the research of fluorescent chemical sensors has become more and more prominent,especially for the detection of some heavy metals or highly toxic ions.In this thesis,we explorded a fluorescence sensor based on Salamo-type ligands for the detection of cyanide ions.This is the first time we studied the ability of the Salamo-type compounds to recognize cyanide ions.We will investigate the future of Salamo-type compounds based on fluorescence sensors.It is of great significance.In this thesis,we mainly synthesized four kinds of Salamo-type ligands,and studied their crystal structures and potential photophysical properties of the metal complexes based on these ligands,derived its potential application as a luminescent materials.One of the bis?Salamo?-type tetraoxime ligands can be used as a fluorescent chemical sensor to identify cyanide ions for further study.The full thesis is divided into four chapters:First,this chapter mainly elaborates on the research background.Emphasis is placed on the development of coordination chemistry,including recent research on Salen-type and Salamo-type compounds,recent research on fluorescence chemical sensors,ion recognition mechanisms,and representative examples.In addition,the significance of the topic of the thesis is elaborated.Second,in this chapter,we designed and synthesized a Salamo-type bisoxime ligand?H₂L¹?through synthesis reaction.Two mononuclear metal complexes were obtained by the reaction of ligand H₂L¹ and copper???acetate.Interestingly,an unexpected new ligand H₄L² was obtained during the process of reaction.The structures of the two complexes were then determined by X-ray single crystal diffractometry.The structures and properties of the ligand and its Co???metal complexes were then determined using characterization methods such as UV-vis spectrometer and fluorescence spectrometer.Finally,the supermolecular configurations of two complexes were analyzed and discussed.Third,we have synthesized a bis?Salamo?-type tetraoxime ligand H₃L³,and obtained two different structures of dinuclear metal complexes generated from the reaction of the ligand H₃L³ with zinc???and cobalt???acetates.The corresponding crystal structures were measured by X-ray single crystal diffractometry,their structural differences and supramolecular structures were analyzed,and the fluorescence properties of the two binuclear complexes are discussed.Fourth,another bis?Salamo?-type ligand H₃L⁴ was synthesized by similar methods,and the possibility of ligand H₃L⁴ as a cya1ide ions fluorescence chemical sensor was explored.By adding different anions to the ligand H₃L⁴,it was found that H₃L⁴ can selectively recognize cyanide ions.At the same time,we calculated the minimum detection limit of H₃L⁴ as a fluorescence chemical sensor for cyanide ions and the binding constant of H₃L⁴ to cyanide ions.Finally,we explored the acid-base environment of H₃L⁴ to identify cyanide ions,and concluded that H₃L⁴ can recognize cyanide ions under alkaline conditions.