Synthesis,Characterization And Photophysical Properties Of Cyano/Tetrazolyl Bipyridine Cuprous Phosphine Complexes

Luminescent metal complexes have important applications in organic light-emitting devices(OLEDs),light-emitting electrochemical cells(LEECs),solar cells,luminescent sensors,biological probes and biological labeling.Copper(I)complexes has become a class of important and excellent emissive metal complexes materials,because of high relative abundance,low cost,environmentally friendly and unique and intense luminescence properties.In this thesis,a new class of copper(I)complexes have been designed and synthesized by using 6-cyano-2,2’-bipyridine and 6-tetrazolyl-2,2’-bipyridine ligand,combined with the flexible and rigid bisphosphine ligands.The specific research contents are summarized as follows:Three luminescent mononuclear copper(I)complexes have been successfully synthesized by using 6-cyano-2,2’-bipyridine(cbpy)and 6-cyano-4,4’-dimethyl-2,2’-bipyridine(cmbpy)as nitrogen ligands combined with two πelectron rich rigid bisphosphine ligands 4,5-bisdiphenylphosphine-9,9-dimethylxanthene(xantphos)and bis[(2-diphenylphosphino)phenyl]ether(POP)reacted with[Cu(CH3CN)4](ClO4).Complexes 1-3 are all four-coordinated with two N donors of the 2,2’-bipyridyl segment and the two phosphine atoms of the rigid bisphosphine ligand,forming a markkedly distorted N2P2 tetrahedron.At room temperature,complexes 1-3 display good emissive properties in both solid and liquid states.The results show that the introduction of the two methyl groups into the 4,4 ’position of the 6-cyano-2,2’-bipyridine significantly enhances the luminescence properties of the Cu(I)complexes.Three novel Cu(I)complexes 4-6 have been successfully synthesized by using 6-cyano-2,2’-bipyridine(cbpy)and 6-cyano-4,4’-dimethyl-2,2’-bipyridine(cmbpy)combined with flexible bisphosphine ligand(bis(diphenylphosphine)methane(dppm)and 1,3-bis(diphenylphosphino)propane(dppp))reacted with[Cu(CH3CN)4](ClO4).It is shown that dppm as the auxiliary phosphine ligand obtain bridged dinuclear copper(I)complexes 4,while dppp as the auxiliary phosphine ligand get mononuclear copper(I)complexes 5 and 6.The[Cu2(μ-dppm)2]2+unit of complex 4 exhibits an eight-membered ring structure of Cu2P4C2,while the copper(I)ion of complexes 5 and 6 are all four-coordinated with two N atoms from 2,2’-bipyridyl segment and the two P atoms from disphosphine ligand,form a markedly distorted P2N2 tetrahedron.It is demonstrated that complexes 4-6 exhibit good luminescence properties in both solution and solids at ambient temperature.In addition,dinuclear Cu(I)complexes have significantly improved luminescence quantum efficiency than mononuclear Cu(I)complexes.Four new Cu(I)complexes 7-10 have been synthesized via the successive reaction of[Cu(CH3CN)4](ClO4)with nitrogen ligands 6-(1H-tetrazol-5-yl)-2,2’-bipyridine(tbpyH)or 6-(1-ethyl-tetrazol-5-yl)-2,2’-bipyridine(etbpy)and bisphosphine ligand bis[(2-diphenylphosphino)phenyl]ether(POP)or 4,5-bisbiphenylphosphine-9,9-dimethylxanthracene(xantphos).The single crystal structural analysis indicates that complexes 7-10 are all in four-coordination mode,however,the structure of complex 10 markedly differ from complexes 7-9 because the sources of the coordinated nitrogen atoms are different.In complex 10,the copper(I)is coordinated with one nitrogen atom from tetrazole and another from the adjacent pyridine ring.In complexes 7-9,the sources of the coordinated nitrogen atoms are all from bipyridine rings.Different structures lead to significant differences in the properties of the complexes.Luminescence measurements indicate that only complex 10 displays good emission properties in both solid and solution at room temperature.