Synthesis, Characterization And Application Of Copper Based Nanocluster Materials

Metal nanoclusters?MNCs?containing several to a few hundreds of atoms,and often show molecule-like electrical and opticalproperties.Due to their ultra small size,high photostability,high fluorescence quantum yield,low toxicity,good water solubility,and good biocompatibility,they have exhibited potential applications in the fileds such as cell imaging,biological tracer,environmental detection,biosensing,catalysis,etc.Copper is a cheap and earth abundant element.Compared to other noble metal nanocluster material,nanocopper is unstable in the air and easy to be oxidated as copper oxide.Therefore,there are less copper based nanoclusters than others till now.It has been reported that polymers,single-chain/double-stranded DNA,proteins/peptides and other macromolecules are used as stabilizing agents to protect metal nanoclusters.Small molecules contain mercapto group have attracted much attention to used as stabilizer and reductant to protect nanoclusters in recent years.2-amino-5-thiol-1,3,4-thiazolide?AMTD?and 2,5-dimercapto-1,3,4-thiadi-azole?DMTD?have been used for the synthesis of copper nanoclusters?AMTD-Ac-CuNCs?and copper sulfide nanoclusters?Cu₉S₅NCs?at room temperature in this paper.Furthermore,Ag-CuNCs gel-nanocomposite?Ag-CuNCs@FA?has beenprepared by combining the fluorescent Cys-CuNCs with AgNPs and folic acid hydrogel.These materials were characterized by FL,UV-vis,XPS,FT-IR,Raman,¹HNMR and TEM,etc,respectively.The expertiment results indicated that they have potential applications in sensing,catalysis and as the substrate monitoring reaction of SERS respectively.The paper is divided into the following parts:?1?Synthesis of a novel copper nanoclusters?AMTD-Ac-CuNCs?stabilized by2-amino-5-thiol-1,3,4-thiazolide?AMTD?and acetate?Ac^-?simultaneously.The nanoclusters has been characterized by UV-vis,TEM,MS,XPS,etc.The CuNCs obtained was ultrasensitive response to water,the fluorescence"turns on"and the fluorescence intensity increases rapidly with the increase of water content.The material can be utilized fordetecting trace water in organic solvents such as ethanol,THF,acetone and acetonitrile.The detection limits are as low as 0.036%,0.018%,0.024%and 0.026%,respectively.In addition,the aqueous solution of the AMTD-Ac-CuNCs has a strong fluorescence,but its fluorescence"turns off"in the solution of Fe³⁺.The detection range is 0⁵?mol·L^-1,and the detection limit is 0.14?mol·L^-1.We have also discussed the mechanism of AMTD-Ac-CuNCs with water molecules.?2?Cu₉S₅ nanoclusters?Cu₉S₅NCs?with photoluminescence emission in the visible region have been synthesized via a simple treatment of copper-2,5-dimercapto-1,3,4-thiadiazole?Cu?II?-DMTD?coordination polymer with ammonium hydroxide.This procedure involves a desulfurative C-N cross-coupling route,in which one mercapto group was replaced by amine,resulting in2-mercapto-5-amine-1,3,4-thiadiazole?AMTD?as protecting agent for Cu₉S₅ NCs.The material obtained has been characterized by SEM,UV-vis,TEM,IR,XPS,FL,etc.The product exhibits a fluorescence emission at 598 nm with a quantum yield???0.068.The as-prepared Cu₉S₅ NCs were employed as a broad-range p H sensor by virtue of the fluorescence intensity responding sensitively to pH fluctuating in a linear range of 3.0¹0.0.Obviously the materisl obtained is superior to the other materials for p H sensing.?3?Ag-CuNCs@FA nanocomposites were prepared by embedding Cys-CuNCs and AgNPs in the hydrogel matrix of folic acid.The material has been characterized by SEM,TEM,XRD,IR,XPS,Raman,etc.It exhibites excellent peroxidase-like activity and rapidly catalyze oxidation of theperoxidase substrate 3,3?,5,5?-tetramethylbenzidine?TMB?in the presence of H₂O₂.On the basis of the excellent SERS properties of Ag-CuNCs@FA nanocomposites,the catalytic oxidation of TMB can be monitored by SERS.?4?Other work:AgNPs/Ag-AMTD-OXA gel-nanocomposites have been synthesized by 2-amino-5-thiol-1,3,4thiazole?AMTD?,oxalic acid?OXA?and AgNO₃ in DMF/H₂O.The effects of OXA on the amounts and the size of AgNPs,the stability of the gel were also discussed.The experimental results demonstrate that the nanocomposites obtained can be used for the removal of Hg²⁺in waste water.The gel-nanocomposites we preparedmay be a potential excellent material to treat wastewater.