Synthesis And Characterization Of Stimuli-Responsive Pyridyl-Diazole-Based Copper(Ⅰ) Luminescent Complexes

Stimuli-responsive luminescent materials are a class of materials whose luminescent properties such as luminescent color and intensity can respond to external stimuli such as temperature,electricity,force,and vapor.Stimuli-responsive luminescent materials have attracted much attention from chemistry and materials researchers because of their potential applications in sensing,security,and storage.The luminescent complexes based on the copper element of high abundance,low price,and environmentally friendness have diverse structures and unique luminescence properties,and their luminescence properties are easy to change with the changes of structure and environment.These advantages make Cu（Ⅰ）luminescent complexes possible to be a good candidate of constructing stimuli-responsive luminescent materials.In this thesis,two series of stimuli-responsive luminescence complexes were designed and synthesized using the pyridyl-diazole ligands.Through the study on the structures and properties,the relationships between structure and weak interaction and luminescence and stimuli-responsive luminescence were revealed.1.Using 4,8,8-trimethyl-3-pyridine-2-yl-4,5,6,7-tetrahydro-4,7-methylene indazole（pydz H）and bis（diphenylphosphino）amine（dppa）ligands and changing the anions,three binuclearcopper（I）complexes[{Cu₂（pydz H）}₂（μ-dppa）₂]（Cl O₄）₂（1）,[{Cu₂（pydz H）}₂（μ-dppa）₂]（BF₄）₂（2）and[{Cu₂（pydz H）}₂（μ-dppa）₂]（PF₆）₂（3）were synthesized.Complexes 1?3 are all binuclear,and contain an identical{Cu₂（μ-dppa）}₂unit.Copper（I）ions are all four-coordinated and exhibit a distorted tetrahedral configuration.Only the N-H???X hydrogen bonds with different anions exist in the crystal structures of complexes1?3,and complexes 1?3 all exhibit luminescence mechanochromism.By Fourier-transform infrared（FT-IR）and X-ray powder diffraction（PXRD）analyses,it is demonstrated that the stimuli-responsive luminescence is mainly caused by the destruction and recovery of N-H???X（X=O,F）hydrogen bonds caused by grinding and CH₂Cl₂vapor.This results in the difference of the LUMO-HOMO and the luminescent color change of complexes 1?3.In addition,the luminescence properties and stimuli-responsive luminescence of copper（I）complexes can be effectively regulated by changing the type and strength of hydrogen bonds.2.Using(3-（2?-pyridinyl）pyrazole（pypz H）and bis（diphenylphosphino）methane（dppm）and selecting(3-（2?-pyridinyl）pyrazole and pyrazole,two copper（I）luminescenct complexes[{Cu₂（μ-η¹（N）η²（N,N）-pypz）}（pypzh）（μ-dppm）₂]（Cl O₄）₂（4）,[{Cu₂（μ-η¹（N）η²（N,N）-pypz）}（pyrazol）（μ-dppm）₂]（Cl O₄）₂（5）were synthesized.Both complexes 4 and 5 are binuclear,and Cu（Ⅰ）ions are four-coordinated and exhibit a distorted tetrahedral configuration.The destruction and restoration of ordered molecular packing are caused by the formation and destruction of intramolecular N-H???πinteractions.Different from complex 5,complex 4 exhibits the luminescence properties in response to the pyridine vapor.To explore the luminescence properties in response to the pyridine vapor of 4,[{Cu₂（μ-η¹（N）η²（N,N）-pypz）}（pyridine）（μ-dppm）₂]（Cl O₄）₂（6）was designed and synthesized.By comparing the PXRD and solid-state emission spectra of complex 4 and 6,it is demonstrated that the luminescence properties in response to the pyridine vapor of complex 4is due to the ligand exchange.Compared with complex 5,the solid-state luminescence of complex 4 shows a blue shift,which is due to the introduction of the pyridine group,enlarging the conjugate system of ligand and raising the LUMO level of copper（I）complex.This indicates that introducing the substituents into nitrogen ligand and changing the conjugation of nitrogen ligand can effectively regulate the luminescence properties and stimuli-responsive behavior of copper（Ⅰ） complexes.