Synthesis and Luminescence Properties of a New Complex of Divalent Europium with Cinnamic Acid, Eu(L)2(THF)4 (L = Cinnamate Anion, С6H5СH=СHCOO–)
摘要
A previously unknown luminescent complex of divalent europium, Eu(L)2(THF)4 (L = cinnamate anion, С6H5СH=СHCOO–), was prepared by the reaction of europium(III) cinnamate crystal hydrate Eu(L)3∙H2O with diisobutylaluminum hydride (iso-C4H9)2AlH in tetrahydrofuran at room temperature and atmospheric pressure. The complex Eu(L)2(THF)4 was isolated in the solid state and was characterized by complexometric titration (Eu2+) and elemental analysis (C, H, O). The yield of the complex Eu(L)2(THF)4 was 68%. The quantum yield of the photoluminescence (PL) of the complex (φPL = 0.05), the PL and PL excitation spectra, and the lifetime (τ = 377 ns) of the europium excited state, Eu2+*, in the complex were measured. The PL of the complex Eu(L)2(THF)4 is due to the interconfigurational transition 4f65d1 → 4f7 and is manifested as a broad diffuse band in the green part of the spectrum (λPL = 515 nm) with the nanosecond lifetime of the excited Eu2+* ions. The complex Eu(L)2(THF)4 exhibiting bright PL visible by naked eye can be used as a phosphor in the development of new materials with preset photophysical properties.