Coinage Metal Nanocluster Construction And Fluorescence Response Based On Hydrogen Sulfide Stimulation

Atomically precise coinage metal nanoclusters fill the gap between discrete atoms and plasma nanoparticles,and provide a perfect opportunity to study the quantum effect and the precise structure property correlation at the atomic level.The synthesis of atomic level accurate coinage metal nanoclusters has become a prerequisite for the study of "structure-activity relationship".In recent years,with the development of Xray single crystal diffraction technology,the synthesis of atomic level accurate coinage metal nanoclusters has become an important research topic,more and more accurate structures of coinage metal nanoclusters have been determined,which greatly stimulates chemists' enthusiasm for exploring the properties of coinage metal nanoclusters.Among them,coinage metal nanoclusters which are sensitive to stimulation have great application prospects in sensing and detection.Among them,stimulant inducers such as oxygen molecules,metal ions and various solvent molecules have been reported.Hence,it is expected to be applied in the field of sensing.However,the thermodynamic instability of coinage metal clusters preclude the study of their application.In view of above,this paper uses the method of "kill two birds with one stone" to realize the construction of coinage metal nanoclusters and the detection of hydrogen sulfide by using hydrogen sulfide to provide sulfide ion template.The specific work is as follows:we prepared a chain-like thiolated Ag(I)complex?[Ag18StBu)10(NO3)8CH3CN)2(H2O)2]·[Ag18(StBu)10(NO)3)8(CH3CN)6]}n(abbreviated as Ag18)in which Ag18 cluster pairs are connected to 1D chain through NO3-.The solution containing Ag18 reacted with hydrogen sulfide with controlled concentration,promptly producing another identifiable and bright red-emitting highnuclearity silver(I)cluster,Ag62(S)13(StBu)32(NO3)4(abbreviated as Ag62).We tracked its transformation using time-dependent electrospray ionization mass spectrometry(ESI-MS),UV-Vis absorption and photoluminescence spectra.Based on this cluster transformation,we further developed an ultra-sensitive turn-on sensor detecting H2S gas with an ultrafast response time(30 s)at a low detection limit(0.13 ppm).This work opens a new way of understanding the growth of metal clusters and developing their luminescent sensing applications.Two copper-phosphine complexes,[Cu2(dppm)2(NO3)2](Cu2-1)and[Cu2(dppm)2(CH3CN)4](PF6)2(Cu2-2)were prepared by one pot method.first,through the reaction of Cu2-1 solution with hydrogen sulfide,and then using PF6-for anion exchange,a yellow bulk crystal with the molecular formula of[Cu4(S)(dppm)4](PF6)2(Cu4)was successfully crystallized.In the process of transformation,hydrogen sulfide"turn-on" the visible florescence with the expansion of copper nuclearity.Based on this,we have successfully obtained a ratio fluorescent hydrogen sulfide probe Cu2-2 by adjusting the anions of copper phosphine precursor.The reacting of Cu2-2 with hydrogen sulfide also produced Cu4.The transformation process was traced by electrospray ionization mass spectrometry(ESI-MS),31P {1H} NMR spectrum,UVVis absorption spectrum and photoluminescence spectrum,and the transformation process was speculated.After calculation,the detection limit of Cu2-1 is 0.17 ppm.Hence,the copper-phosphine complex can be used as an ultra-sensitive fluorescent probe for hydrogen sulfide.