The Study Of The Preparation And Optical Features Of High-Nucleus Silver Alkynyl Clusters Constructed By Diphenylphosphoric Ligands

High-nucleus alkyne silver clusters have become a focus of attention due to their diverse molecular structures and rich physicochemical properties.However,the formation process involves the self-assembly of several complex components,including template anions,metal ions,organic ligands and anti-balance ions,and some of the silver clusters are prone to oxidative decomposition when exposed to light or air,which makes the construction of high-nucleus silver clusters very difficult.Previous studies have shown that a series of high-nucleus alkyne silver clusters with novel structures and unique properties can be prepared by using various inorganic or organic anions as templates,and the introduction of second ligands such as pentafluorobenzoic acid and diphenyl phosphate into the surface of the silver clusters can significantly affect the optical properties of the high-nucleus alkyne silver clusters.In this thesis,based on the use of a new negative tetrahedral template anion arsenate(AsO43-)as a template for the construction of a series of high-nucleus alkyne silver clusters with diphenyl phosphate as a ligand,the group further constructed a series of highnucleus alkyne silver clusters with negative divalent tetrahedral anions such as chromate(CrO42-),sulfate(SO42-),molybdate(MoO42-),and molybdenum polyacid ion[Mo6O22]8-as a template for the construction of a series of high-nucleus alkyne silver clusters with diphenyl phosphate as a ligand.The high-nucleus alkyne silver clusters with diphenyl phosphate as ligand were constructed as templates,and their thermal stability and optical properties were comparatively studied by thermogravimetric analysis,solid-state UV absorption spectroscopy and fluorescence spectroscopy along with the comparative analysis of their structural changes.The main research contents for this thesis are as follows:1.Two examples of one-dimensional alkyne-silver coordination polymers without template anion[Ag16(C≡CtBu)6(tfa)6(Ph2PO2)4(CH3OH)]n(1)and[Ag21(C≡CtBu)8(tfa)6(Ph2PO2)7]n(2)were prepared by adjusting the amount of diphenyl phosphoric acid,indicating that adjusting the amount of the second ligand diphenyl phosphoric acid can significantly change the structure and composition of the alkyne-silver clusters.The results of thermogravimetric analysis showed that the decomposition temperature of the two examples of one-dimensional alkyne-silver coordination polymers was up to 250 ℃,which exhibited good thermal stability.The optical properties showed that the energy gap of both ligand polymers was 3.00 eV,and the solid powders fluoresced bright orange at 77 K.2.Using negative divalent tetrahedral anions such as chromate(CrO42-),sulfate(SO42-),and mol ybdate(MoO42-)as templates,a series of high-nucleus alkyne silver clusters[(CrO4)@Ag19(C≡CrBu)8(Ph2PO2)6(tfa)3(CH3OH)2](3)、[(SO4)@Ag19(C≡CtBu)8(Ph2PO2)6(tfa)3CH3OH)2](4)、[(MoO4)@A g20(C≡CtBu)8(Ph2PO2)7(tfa)2]·(tfa-)(5)、[(CrO4)@Ag19(C≡CtBu)8(Ph2PO2)7(OTf)]·(OH-)(6)and[(M oO4)@Ag18(C≡CtBu)8(Ph2PO2)7]·(OH-)(7).The hydrogen-bonded supramolecular surface structures such as CH3O-H...O2CCF3 and CH3O-H...O2CPPh2 and Ag+…π surface supramolecular interaction were observed on the surfaces of clusters 3 and 4 by single-crystal diffraction analysis.The results of t hermogravimetric analysis showed that the thermal decomposition temperature of the five case cluster s was around 200℃,which exhibited good thermal stability.The study of their optical properties sho wed that the energy gaps of the five cases of clusters were 2.37 eV,3.70 eV,3.57 eV,2.24 eV and 3.72 eV,respectively,and the optical absorption properties of the two cases of clusters with chromate as th e anion template were better,and the solid powders of clusters 4,5 and 7 fluoresced light yellow,brig ht white and bright white at 77 K,respectively.3.An example of high-nucleus alkyne silver clusters[(Mo6O22)@Ag40(C≡CtBu)20(tfa)10(Ph2PO2)2(CH3OH)2](8)containing two diphenylphosphonates on the surface was prepared using the molybdolytic[Mo6O22]8-anion as a template.Thermogravimetric analysis shows that its thermal decomposition temperature is 190℃,which is slightly lower than that of the series of alkyne silver clusters with negative divalent tetrahedral anions as templates.The study of its optical properties shows that its optical energy gap is 3.01 eV and its solid powder fluoresces white at 77 K,which is a potential low-temperature fluorescent material.