Syntheses And Luminescence Properties Of Rare Earth Complexes With 2'-Hydroxyacetophenone And Its Derivatives

In this paper,β-diketone-like compounds,for example,2'-Hydroxyacetophenone (HOHAP) and its derivatives,4,6-diacetyl-resorcinol,2'-Hydroxychalcone and its derivatives,5-Acetamido-2-hydroxyacetophenone,N,N,N',N'-tetraacetylethylenediamine and so on,were synthesized.All structures were proved via elementary analysis,IR,UV, and by contrasting their melting point with their reference.Based experimental,all the ligands are coordinated to rare earth ion via the carbonyl and phenolic oxygens,and 4,6-diacetyl-resorcinol is concluded to be bis-bidentate donor.The complexes were characterized by elementary analysis,IR,UV and thermo-gravimetric analysis.The results show that in these complexes,only those of Eu(â…¢) with 4,6-diacetyl-resorcinol and 2'-Hydroxyacetophenone can emit strong red fluorescence,and the position of fluorescence emission is around 611 nm.Other complexes cannot emit fluorescence.The phenomenon was interpreted by electron-effect and energy-matching mechanism.The "Antenna effect" between the rare earth ions and the ligands was proved again.Energy transfer mechanism of the luminescence in the complexes was discussed.In order to eliminate O-H oscillators in the short range and reduce the nonradiative decay from the excited state of Ln(â…¢),some synergic ligands with aromatic segment, 1,10-phenanthroline-1-oxide,1,10-Phenanthroline-5,6-dioxide and 2,2'-Bipyridine N,N' -Dioxide were synthesized.Because when they were coordinated with Eu(â…¢) via N atom, the coordination sphere should be supplemented.Quenching water molecules in the coordination sphere of lanthanide ion can be replaced by the synergic ligand and thus the luminescence intensity of the complex is enhanced.Based on our luminescence observations,the luminescence intensity of the ternary complexes is larger than that of the binary complexes,and the life time and quantum yield were increased.The Gd³⁺ complexes with 2'-Hydroxyacetophenone and 4,6-diacetyl-resorcinol were prepared and the phosphorescence spectra were measured,the triplet state of HOHAP(L¹) can be calculated to be 23095cm^-1(21739cm^-1).With that we can explain the differences in luminescence intensity. Crystal structure for L⁷ was measured by X-ray diffractomer.Crystallographic data was shown as follows:L⁷:C₁₀H₁₆N₂O₄,crystal system monoclinic,space group P2₁/c,a =5.95220(10)(??,b=10.2591(2)(?),c=9.3392(2)(?),β=95.6980(10)°,V=567.473(19) (?)³,Z=2,F=244,R₁(＞2σ(I))=0.0390,wg₂(＞2σ(I))=0.1093.