| Copper(?)complexes have been considered to be a family of promising luminescent materials,because of relative abundance,low cost,and environment benignancy of copper as well as structural diversity,tunable luminescence properties,long excited-state lifetimes of Cu(?)compounds.In addition,Cu(?)complexes often show intense phosphorescence,thermally activated delayed fluorescence,stimuli-responsive(temperature,mechanical grinding,pressure,vapour,etc.)luminescence.In this thesis,two new series of eleven Cu(?)complexes have been designed and synthesized successfully by using the triazole-based chelating ligands including 3-(2'-pyridyl)-1,2,4-triazole and 3-(2'-pyrimidyl)-1,2,4-triazole as well as the diphosphine ligands including 1,1'-bis(diphenylphosphino)ferrocene and bis(diphenylphosphino)methane,and the structural and photophysical properties of the resulting Cu(?)species have also been investigated.1.A new series of four cationic and three neutral heterobimetallic copper(I)complexes bearing 1,1'-bis(diphenyl-phosphino)ferrocene and functional 3-(2'-pyridyl)-1,2,4-triazole have been synthesized.They all present a highly distorted tetrahedral P2N2 geometry around Cu(?),in which functional 3-(2'-pyridyl)-1,2,4-triazole adopts either mono-anionic ?2(N1,N2)or neutral ?2(N1,N2)or ?2(N1,N4)bonding mode,depending on the substituent and NH(?)N-conversion of 1,2,4-triazole.All these Cu(?)complexes are air-stable in solution and solid states.All these 1,2,4-triazole-based complexes show a relatively weak and broadened low-energy absorption band,attributed to the charge-transfer transitions,as suggested by time-dependent density functional theory(TDDFT)calculations,which is more remarkably influenced by the NH(?)N-conversion of 1,2,4-triazole relative to the variation of the substituent.Since the charge-transfer excited state is quenched by a photoinduced intramolecular energy transfer from the {Cu(N^N)(PP)} moiety to the ferrocene,as supported by the lowered oxidation potential of the ferrocene in comparison to the Cu(?)center,these dppf-based Cu(?)complexes all show no detectable emission in solution and solid states at room temperature and at 77 K.2.Based on our previous research,four novel binuclear Cu(?)complexes 8-11 bearing both functional 3-(2'-pyrimidine)-1,2,4-triazole and bis(diphenylphosphino)methane have been synthesized.The Cu(?)ions of complexes 9 and 11 are all four-coordinated,and one of the Cu(?)ions coordinates with two bis(diphenylphosphino)methane ligands and two N donors of the 3-(2'-pyrimidine)-1,2,4-triazole to form a markedly distorted P2N2 tetrahedron,the other coordinates with two P atoms of two bis(diphenylphosphino)methane ligands,one N atom of the triazole ring form the 3-(2'-pyrimidine)-1,2,4-triazole ligand and one acetonitrile solvent molecule to form a distorted tetrahedral model of N2P2.The two Cu(?)ions of complexes 8 and 10 adopt two different coordination modes:one of the Cu(?)ions are four-coordinated and in a highly distorted N2P2 tetrahedral environment,the another Cu(?)ion are three-coordinated,in a distorted N2P trigonal planar arrangement.All these Cu(?)complexes display an eight-membered Cu2C2P4 ring of {Cu(?-dppm)2Cu} unit,and these four complexes all adopt the boat-boat conformation.These Cu(?)complexes are triply bridged by a charge-neutral(8 and 9)or monoanionic(10 and 11)3-(2'-pyrimidinyl)-1,2,4-triazole in a?-?1(N),?2(N,N)tridentate binding mode.All the Cu(?)complexes 8-11 are stable in solid state and they are all emissive in solution and in the solid state at ambient temperature,and their emission properties can be well-modulated via structural modification of 3-(2'-pyrimidinyl)-1,2,4-triazole including the alteration of the substituent(-CF3 and-C(CH3)3)and the introduction of acetonitrile solvent molecules. |
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