Synthesis And Characterization Of Copper(?)Complexes Containing Alkynyl And Phosphines

Alkynyl metal complexes which are coordinately formed by metal and linear,have highly stable alkynyl processing?electrons,and excellent nonlinear optical effects,fluorescence,photoconductivity,electron transport,molecular wire and liquid crystal properties.The alkynyl group can be connected with metal by?bond to form a linear structure,or bridged with the metal through?-bond to form a more stable cluster.The Cu(I)complexes with thermally activated delayed fluorescence(TADF)effect can harvest triplet excitons through the reverse intersystem crossing,and theoretically achieve 100%internal quantum efficiency,which is expected to replace heavy transition metals such as iridium and platinum complexes.Among them,the reported copper halide complexes with rigid diphosphines have aroused the interest of researchers because they are comparable to green iridium complexes.However,the study on Cu(I)complexes containing alkynyl and diphosphines are rarely reported.This article introduces the present situation of the research in this field,and puts forward the research idea and content.Three ligands(L₁,L₂and L₃)containing alkynyl and diphosphines were synthesized and reacted with Cu(I)halides to obtain seven mononuclear three-coordinate Cu(I)complexes.These complexes were characterized on the structures and photophysical properties by nuclear magnetic resonance(NMR),mass spectrometry(MS),infrared spectroscopy(IR),X-ray single crystal diffraction,ultraviolet-visible absorption spectroscopy(UV-vis),fluorescence spectroscopy,and thermogravimetric analysis(TGA).Luminescence mechanism was analysized by density functional theory(DFT)calculations.The research results show that the C?C group of complex 1-3 is not coordinated with copper,and the complexes emit greenish yellow light at room temperature.The maximum emission wavelengths are 580,583 and 572 nm,respectively,with quantum efficiencies of 2.84?3.43%,lifetimes of 1.7?6.3 ns,the emissions are prompt fluorescence,which mainly come from MLCT and XLCT.The C?C group in complexes 4-6 is coordinated with copper by?bond,and the complexes emit greenish yellow light at room temperature.The maximum emission wavelengths of solid complexes 4-6 are538?575 nm,with quantum efficiencies of 0.08?0.30%,lifetimes of 0.27?16.01?s.Complexes 4-6 display TADF,which mainly comes from MLCT and XLCT.The C?C group in complex 7 is coordinated with copper by?bond.At room temperature the solid complex 7 emits yellow green light,with the maximum emission wavelength of 550 nm,the quantum efficiency of 0.27%,and the lifetime of 11.1 ns.The emission is prompt fluorescence,which mainly originates from XLCT and MLCT.