Metal-Organic Salts Constructed By Second Sphere Coordination Used As The Fluorescence Molecular Probe And Inhibitor Of Urease And Nitrifying Bacteria

Metal-organic salts?MOSs?refer to metal organic compounds constructed by metal ions and organic cations,the non-covalent interactions in MOSs,sometimes refers to second sphere interactions of the cationic ligands directly bound to the first coordination sphere of the metal anions.The compounds have attracted much attention due to their fansinating structural topologies and potential applications in recent years.It has been successfully used in metalloenzyme chemistry,solid-state chemistry,gas adsorption,selective gold separation,optical materials,and recently following single-crystal-to-single-crystal reactions to study the dynamic behaviour of various non-porous materials.To our best acknowledge,very few works have been reported in jack bean urease and nitrifying bacteria by using MOSs as inhibitors and little attention has been given to the application of second sphere adducts as sensors for pesticide intermediate nitroaromatic detection until now.In this thesis,we have carried out the following works aimed to design new metal-organic salts with specific structures and properties through second-sphere interactions.?1?The derivatives 4,4'-methylenedicyclohexanamine?L1?,4,4'-methylenebis?N-?pyridin-2-ylmethyl?cyclohexanamine??L2?,4,4'-methylenebis?N-?pyridin-3-ylmethyl?cyclohexanamine??L3?,4,4'-methylenebis?2,6-diethyl-N-?naphthalen-1-ylmethyl?aniline??L4?,N,N,N',N'-tetrakis?2-fluorobenzyl?ethane-1,2-diamine?L5?and N,N,N',N'-tetrakis?3-fluorobenzyl?ethane-1,2-diamine?L6?were designed and synthesized.L1—L6can be quadruply protonated and coordinated with the[MX₄]^2-?M=Cd,Co,Cu,Zn,Pb;X=Cl,Br?to form a series of MOSs?1—19?,The structures of all the complexes were characterized by IR,NMR,SC-XRD and P-XRD.?2?The inhibitory activities against jack bean urease of ligand L1—L6 and complexes 1—19 were evaluated according to the phenolred method.Crystal 8,13,16showed obvious inhibition activities against jack bean urease.The IC₅₀ of 8 was 0.34±0.01m??0.5 h?and 0.93±0.01mM?3 h?,the IC₅₀ of 13 was IC₅₀=0.42±0.02mM?0.5h?,IC₅₀=1.12±0.03mM?3 h?,the IC₅₀ of 16 was IC₅₀=0.89±0.01mM?0.5 h?,IC₅₀=1.87±0.01mM?3 h?.The docking of crystal 8,13 and 16 with urease activity sites was studied by using autodock software.The result showed that crystal 8 was bound to urease mainly by hydrogen bonding,hydrophobic action and?-?stacking.The crystal 13 was bound to urease mainly by hydrogen bonding,hydrophobic action.Two configurations docking with urease activity sites in the crystal 16,mainly in the form of configuration?combined with urease.The result showed that crystal 16 was bound to urease mainly by hydrogen bonding,hydrophobic action and?-?stacking.The three metal-organic salts inhibit urease activities by occupying the space near the urease activity center and affecting the binding of substrate to the urease.The effections of inhibitor on urease activity were crystal 8>crystal 13>crystal 16.?3?Fluorescent molecular probes were prepared by secondary coordination to detect nitroaromatic compounds.The solid state fluorescence indicated that the maximum emission intensities of complex 11 and 14 were higher than the other complexes of the same series.The fluorescence emission spectra of complex 11 and 14 in the same amount of different solvents were tested.The fluorescence quenching phenomenon was found in complex 11 and 14 in the presence of nitroaromatic explosives.Thus,complex 11 and 14were used as fluorescent molecular probes to detect the nitroaromatic explosives.The limit of detection of nitrobenzene of 11 was 0.66mM,the limit of detection of2-nitrotoluene of 11 was 0.68mM,the limit of detection of 3-nitrotoluene detection of 11was 1.45mM.Complex 11 as fluorescent molecular probe detects nitroaromatic compounds,the sequence base on sensitivity was nitrotoluene>2-nitrotoluene>3-nitrotoluene.The limit of detection of nitrobenzene of 14 was 3.8mM,the limit of detection of 2-nitrotoluene of 14 was 7.9mM,the limit of detection of 3-nitrotoluene detection of 14 was 3.4mM.Complex 14 as fluorescent molecular probe detects nitroaromatic compounds,the sequence base on sensitivity was 3-nitrotoluene>nitrotoluene>2-nitrotoluene.The sensitivity of complex 11 was more than complex 14.?4?The ligand L5,L6 and metal-organic salts 14—19 were incubated in soil to study the inhibition effect on nitrifying bacteria.The incubation results showed that complex 16 have a good inhibition effect on nitrifying bacteria.The nitrification inhibitor dicyandiamide was added to the soil,the content of nitrate nitrogen was 40.04 mg/Kg and the nitrification rate was 67.65%at the 14th day of incubate.The content of nitrate nitrogen was 48.90 mg/Kg and the nitrification rate was 73.18%at the 28th day of incubate.Complex 16 was added to the soil,the content of nitrate nitrogen was 43.48mg/Kg and the nitrification rate was 64.87%at the 14th day of incubate.The content of nitrate nitrogen was 53.33 mg/Kg and the nitrification rate was 70.75%at the 28th day of incubate.The inhibitory effect of complex 16 on nitrifying bacteria was similar with dicyandiamide.Therefore,complex 16 can be used as a new nitrification inhibitor to reduce nitrogen emissions.In this work,crystals 1—19 were prepared by second sphere coordination.Complex8 and 13 showed obvious inhibition activities agaist jack bean urease.Complex 16 can inhibite urease and nitrifying bacteria.Complex 11 and 14 were used as fluorescent molecular probes to detect the pesticide intermediate nitroaromatic compouds.Second sphere coordination chemistry as a novel supramolecular chemistry research method has aroused the interest of many scholars.The specific structures and special properties of functional materials will be developed and applied in the field of daily life.