Study On Synthesis And Properties Of Salicylaldehyde-type Schiff Base Metal Complexes And Fluorescent Sensor

Although cyanide had important applications in the metallurgical industry,electroplating,etc.Its highly toxic nature also brought a huge challenge to health and the ecological environment.Therefore,many research groups were devoted to the research of a simple and efficient method to identify cyanide,and the characteristics of high sensitivity and high selectivity of fluorescent chemical sensor,so it has attracted much attention.Coordination compounds have also been extensively studied by many research groups in the past few decades.Dong Wenkui’s research group developed Salamo type ligand and its derivatives（R-CH=N-O-（CH₂）n-O-N=CH-R）on the basis of Salen ligand（R-CH=N-（CH₂）n-N=CH-R）,and achieved remarkable achievements.The cavity formed by N₂O₂ is easier to coordinate with the transition metal ions,showing better stability.In this thesis,a fluorescent chemical sensor HL¹ which canrecognize CN^-ions efficiently was studied,and its synthesis method and recognition mechanism were discussed.At the same time,three ligands were synthesized based on p-aminoacetophenone allyl oxime and the corresponding six complexes were obtained,then the synthesis,characterization and spectral properties of the ligands and complexes were studied.First,4-aminobenzenesulfonamide was synthesized by multi-step reaction using acetanilide as raw material,and after purification,the fluorescence chemical sensor HL¹ was obtained by reacting with 3-ethoxy salicylaldehyde.After scanning it with 18 kinds of anions,it was found that the chemical sensor HL¹ and CN^-ion combined with obvious fluorescence enhancement,then it was proved that HL¹ has good selectivity to CN^-ion by ion competition experiment.It also calculated that the detection limit was far below the level specified by the World Health Organization.The recognition mechanism of chemical sensor HL¹ for CN^-ion was studied by NMR titration,and the stability of chemical sensor HL¹ was tested according to the change of fluorescence.Then,the O-allylamine hydrochloride was reacted with 4-aminoacetophenone to obtan p-aminoacetophenone allyl oxime,and reacted with 2-hydroxy-1-naphthalaldehyde,2-Hydroxy-3-methoxybenzaldehyde and 5-Chloro-2-hydroxybenzaldehyde to obtan ligands HL²,HL³ and HL⁴,respectively.Two mononuclear complexes[Cu（L²）₂]（1）and[Ni（L²）₂]（2）and a binuclear complex[Ag₂（L²）₂（H₂O）₂]（3）were obtained by the reaction of the ligand HL² with the transition metal salts copper（Ⅱ）acetate,nickel（Ⅱ）acetate and silver（I）nitrate;Two binuclear complexes[Cu₂（L³）₂]（4）and[Cd₂（L³）₂]（5）were obtained by the reaction of ligand HL³ with the transition metal salts copper（Ⅱ）acetate and cadmium（Ⅱ）acetate;A binuclear complex[Cu₂（L⁴）₂]（6）were obtained by the reaction of the ligand HL² with the transition metal salts copper（Ⅱ）acetate.The structures of three ligands and six complexes were characterized and analyzed by IR,UV-Vis and fluorescence spectra.In addition,Hirshfeld’s surface analysis,DFT calculation and supramolecular forces were also studied.