Synthesis Of Several Nitrogen-containing Heterocyclic Ligand-modified Ag-S Nanocluster Coordination Polymers And The Application In Solvent Recognition

Due to the unique properties of organometallic coordination polymers for the application in the fields of optics,magnetism,electrochemistry and so on,they have received considerable attention in the chemical research in recent years.Compared with other metal ions,silver ions have attracted more attentions in the research community because of their various coordination forms and the formation of unique silver-silver interactions.In this thesis,combining with the wide-ranging property tunability of coordination polymer nanomaterials,some novel silver-sulfur cluster coordination polymers were prepared by using nitrogen-containing heterocyclic ligands as bridging molecules.Moreover,the application of these coordination polymers in the detection of solvent moleucles also were investigated.Firstly,a silver coordination polymer with a helical structure was prepared by introducing benzimidazole(Bz)molecule into the Ag-S cluster.It was named Ag-Bz and its basic structural unit was[Ag5(CF3COO)(S/Bu)4(Bz)].The chemical stability and fluorescence intensity after forming the coordination polymer are significantly enhanced compared to the parent Ag-S cluster.The red fluorescence emission was confirmed by density functional theory(DFT)calculations ascribled to the charge transfer process(MLCT)between the organic ligand and the intermediate metal atom.Based on the influence of solvent molecular polarity on the MLCT process,an analytical method for identifying alcohol molecules was established.The linear range of n-butanol in ethanol is 10%-80%,and the detection limit is 3.81%.The linear range of methanol in ethanol is 10%-40%,and the detection limit is 3.75%.Next,using three pyridylcarbonyl hydrazide(p-iah,m-iah,o-iah)as ligands,the effect of nitrogen position in the heterocyclic ring on the formation of coordination polymer structure was investigated.The basic structural unit of obainted silver coordination polymers were[Ag10(CF3COO)4(S'Bu)6(p-iah)2(CH3CN)2],(abbreviated as Agl-iah);[Agio(CF3COO)4(S/Bu)6(m-iah)2(CH3CN)4]n,(abbreviated as Ag2-iah);[Agio(CF3COO)4(StBu)6(o-iah)2(CH3CN)]n,(abbreviated as Ag3-iah),respectively.Ag1-iah,Ag2-iah and Ag3-iash demostrated one-dimensional cross-helix chain,two-dimensional network s and one-dimensional parallel chain structure respectively.Both Ag1-iah and Ag2-iah are formed by the connection of centrally symmetric Ag-S clusters,while Ag3-iah is formed by the connection of asymmetric central clusters.Finally,the stability and optical properties of Ag1-iah,Ag2-iah and Ag3-iah were studied.According to their properties,they were applied to the detection of halogen ions in water and the identification of halogenated alkanes.The fluoresent intensity of Ag1-iah was responded to Cl-,Br-,I-with linear range of 0.1-1.2 mM,0.1-0.8 mM and 0.1-0.6 mM,detection limits of 106 nM,62 nM and 52 nM.Finally,Ag3-iah was applied to detect dichloromethane/trichloromethane in tetrachloride.The linear ranges were 10%-45%and 5%-60%,and the detection limits were 3.08%and 2.27%,respectively.