Synthesis & Characterization Of Pyridyl Phosphine Copper(?) Halide Complexes And Polyoxometalates-based Hybrid Derivatives

Phosphorescent copper?I?complexes,with high photoluminescence quantum yeild,cheap,environment friendly,is becoming one of the hot candidates applied in organic light-emitting diode.In recent years,a variety of copper?I?complexes with thermally activated delayed fluorescence?TADF?effect have been designed and synthesized.Studies have shown that these complexes could convert triplet excitons and harvest singlet excitons by reverse intersystem crossing?RISC?in efficiently at room temperature,making the theory internal quantum efficiency?IQE?of organic light-emitting diodes?OLED?device in theory could reach 100%.Therefore,the design and synthesis of copper?I?complexes with TADF effect have become one of important field in OLED.The derivatization of POMs using organic compounds modified or hybridized to the polyoxometalates?POMs?,can integrate structural topology,adjustable charge,acid-base property,redox property and thermal stability of POMs and organic components,and can expand their applications in catalysis,pharmaceutical chemistry,magnetic and photoelectric materials,et al.In many derivatization methods,covalent hybrid method has the advantages of high reaction selectivity and yield,easily determined the compositions of the structure,which has been becoming a hot issue of POMs-based hybrids.Chapter? IntroductionOn one hand,this chapter briefly introduces the development history,device structure,working principle,and classification of light-emitting materials of OLED,mainly focus on the types of phosphorescent copper?I?complexs and the research status of them are introduced mainly.Moreover,the research progress of TADF materials and copper?I?complexes with TADF effect have also been discussed.On the other hand,it introduces the research progress on the POM-based derivatives including using molecular interactions.The types of covalent hybrids based on a variety of configurations of POMs have been carried on.Finally,the research progress on organosilyl,organophosphonate,organotin,organogermyl derivatives based on monolacunary Keggin-POMs or Dawson-POMs has been reviewed.Chapter? Synthesis,characterization and photophysical properties of pyridyl phosphine copper?I?halide complexes.Luminescent dinuclear copper?I?complexes,[Cu₂X₂?tpyp?₂][X=I,Br,Cl;tpyp=tri?pyridin-2-yl?phosphine],were successfully synthesized by a solvent-assisted solid phase synthesis.A trace amount of the assisting solvent plays a key role in the synthesis.X-ray single crystal diffraction analysis revealed that the dinuclear structure with no Cu···Cu interactions,bridged by two tpyp ligands,was commonly formed in all CuX species.These complexes exhibited bright yellow-green emission in the solid state at room temperature(?_PL=4.70¹6.64%;?_max,em=520⁵30 nm).Emission decay measurement and DFT calculation suggested that the luminescence of three complexes could be assigned to phosphorescence from the triplet metal-to-ligand charge-transfer?³MLCT?excited state,effectively mixed with the halide-toligand charge-transfer?³XLCT?excited state,at 77 K.The source of emission changed to TADF with the same electronic transition nature at room temperature.Chapter? Synthesis and characterization of organophosphonate covalent hybrids based on monolacunary Keggin type heteropolytungstates.Using two monolacunary Keggin type heteropolytungstates[Si W₁₁O₃₉]^8-and[PW₁₁O₃₉]^7-as the inorganic component,4-?diphenyl phosphine?phenylphosphonic acid as the organic component,through phase transfer catalytic synthesis by tetrabutylammonium bromide in acetonitrile,two kinds of organophosphonate derivatives based on Keggin type heteropolytungstates were synthesized successfully.FT-IR,NMR and other test methods showed that the organic components combined with POMs by molar ratio of 2:1.Electron transfer properties of hybrid system were studied by the electronic spectra and cyclic voltammetry,and the results showed that POMs can accept electronics from the conjugated system,which makes electrons transfer and delocalize in the hybrid system.Electrochemical studies showed that the redox properties of POMs were largely preserved in hybrids system.At the same time,they are easier to accept the electrons to be restored.These properties indicate that hybrid derivatives have potential application in electric photocatalytic reduction and photic catalytic degradation of organic dyes,and relevant other fields.Chapter? Electrocatalysis and photocatalysis properties of organophosphonate covalent hybrids based on monolacunary Keggin type heteropolytungstates.Using two kinds of hybrid derivatives as chemical modifier,two chemically modified carbon paste electrode?CPE?was prepared respectively.The cyclic voltammetric behavior of CPEs were investigated in 1M H₂SO₄ solution.Three reversible redox peaks were observed for each CPE.The electrocatalysis ability of these CPEs toward nitrite ion,bromate ion and hydrogen peroxide in the 1M H₂SO₄ solution had been studied and compared.As photocatalysts,under irradiation of 400W high pressure mercury lamp,the catalytic degradation rate of hybrid derivatives toward methylene blue?MB?had been studied and compared by UV absorption spectra.Control experiments displayed that the catalytic performance of hybrid derivatives is superior to pure POMs,and the photocatalysis ability of[PW₁₁O₃₉]^7-series is better than[SiW₁₁O₃₉]^8-series.