Study Of The Grinding-responsive Luminescent Copper(?) Pyridylpyrazolyl Complexes

Stimuli-responsive luminescent materials are the research hotspots of the current luminescent materials due to their good potential applications in sensing and detection,data storage and security protection.It is very important to use low-cost and environmentally friendly copper(?)luminescent complexes to develop stimuli-responsive luminescent materials.In this thesis,two classes of stimuli-responsive copper(?)luminescent complexes have been designed and synthesized by using functionalized 3-(2?-pyridyl)pyrazole and1,1?-bis(diphenylphosphino)methane ligands.Their structures,properties,and stimuli-responsive mechanism have been systematically studied.The detailed research contents are as follows:1.Three binuclear copper(?)complexes bearing the pyridylpyrazole-based ligand(3-(2?-pyridyl)pyrazole(pypz H),5-trifluoromethyl-3-(2?-pyridyl)pyrazole(pyfpz H)and5-tert-butyl-3-(2?-pyridyl)pyrazole(pybpz H))and 1,1?-bis(diphenylphosphino)methane(dppm),[{Cu(pypz H)}₂(?-dppm)₂](Cl O₄)₂(1),[{Cu(pyfpz H)}₂(?-dppm)₂](Cl O₄)₂(2),and[{Cu(pybpz H)}₂(?-dppm)₂](Cl O₄)₂(3),have been synthesized.These Cu(?)complexes all show mechanochromic luminescence and thermally activated delayed fluorescence(TADF)properties.It is shown that the mechanochromic luminescence is caused by the destruction and restoration of the N-H???O hydrogen bond between the pyrazolyl N-H and the neighbouring Cl O₄?anion,affecting the HOMO-LUMO energy gap of Cu(?)complexes.In addition,the luminescence color of Cu(?)complex before and after grinding can be well regulated by changing the substituents on the pyrazole ring(-CF₃,-H,-(CH₃)₃).The difference of luminescence colors is 2<1<3,which is consistent with the electron-donating ability of the substituents.2.By using two pyridylpyrazole ligands(3-(2?-pyridyl)pyrazole(pypz H)and5-trifluoromethyl-3-(2?-pyridyl)pyrazole(pyfpz H))and 1,1?-bis(diphenylphosphino)methane(dppm),two new three-and four-coordinate bimetallic Cu(?)complexes,[{Cu₂(?-?¹(N)?²(N,N)-pypz)}(?-dppm)₂](Cl O₄)?CH₂Cl₂(4)and[{Cu₂(?-?¹(N)?²(N,N)-pyfpz)}(?-dppm)₂](Cl O₄)?CH₂Cl₂(5),have been synthesized under alkaline conditions.In 4 and 5,the coordinationmode of functionalized3-(2?-pyridyl)-pyrazole ligands is?-?¹(N3),?²(N1,N2),that is,Cu1 coordinates with the N1atom on the pyridine ring and the N2 atom on the pyrazole ring,while Cu2 coordinates with the other N3 atom on the pyrazole ring.The two atoms of Cu1 and Cu2 are linked by two dppm phosphine bridging ligands.Complexes 4 shows three-color luminescence conversion,which is due to the loss and recovery of the solvate CH₂Cl₂ molecule and the destruction and recovery of the ordered molecular stacking model caused by the destruction and restoration of the O···H hydrogen bonding interactions around Cl O₄?.Complex 5 shows reversible two-color luminescence conversion,which results from the destruction and restoration of the O···H hydrogen bonding interaction around Cl O₄?.