Study On The Synthesis, Structure And Properties Of Dumbbell-shaped Silver Alkyne Complexes

In recent years,silver clusters have received sustained attention due to its unique structures and its potential applications in catalysis,luminescence,biology,etc.Among them,silver clusters are assembled from a single alkynyl ligand.has hindered the rapid development of the silver acetylides to a certain extent due to its poor solubility and stability.Therefore,the researchers used mixed ligand method or ligand modification method to increase the solubility and stability of silver clusters,and greatly increased the yield of silver clusters,and showed good catalysis and luminescent properties.On the basis of this,six novel silver acetylide clusters were designed and synthesized by introducing phosphine groups into alkynyl ligands by ligand modification method,and their structures and optical properties were studied in detail.First,six dumbbell-like silver acetylide clusters were synthesized by using a new bifunctional ligand Ph2P-C6H4-3-C?CH(L),and obtained their single-crystal x-ray structure,which is a cage-like structure composed of 36 silver atoms.Structural analysis of the six silver acetylide clusters:(1)argentophilic interactions and Ag(?)-ethynide interactions are important for the formation of silver cores,during the self-assembly process of silver acetylides.(2)the introduction of phosphine group into alkynyl ligands not ouly regulates the structure of silver acetylides,but also prevents the infinite growth of silver acetylides,thus increasing the solubility of silver acetylides.(3)?-?interactions,C-H…? interactions,C-H…F interactions,and C-H…O interactions are also found in these complexes,which are essential for stabilizing these silver clusters.(4)The anions like BF4?,ClO4-,and SbF6-are not only counter anions but also they are connected with acetonitrile molecules within the structure as well as L ligands through weak molecular interactions,further consolidate the rigidity and stability of the whole silver acetylides.Second,we have studied the optical properties of complex 1-3.[(CH3CH2)3NH][Ag36L24Cl3(ClO4)6(CH3CN)8](C104)4(1)[Ag36L24Cl3(C03)2(OH)(Py)4(CH3CN)4](BF4)4(2)[(CH3CH2)3NH][Ag36L24Cl3(CH3CN)10](SbF6)10(3)Complexes 1-3 show intense orange luminescence when exposed to UV light at room temperature.Through UV absorption spectra,solid fluorescence emission spectra,binding lifetime and so on,the photoluminescence mainly comes from ligand to metal charge transfer(LMCT)and metal cluster centered transitions(MC)within the silver clusters.In addition,when the temperature is raised or the ultraviolet irradiation time is prolonged,the luminescence intensity of the compounds changes obviously.This kind of interesting optical phenomenon is rare in the silver acetylides,which again shows that the silver acetylide clusters have potential application in optical materials.