高荧光性含锌类水滑石研究

本研究将适量锌离子(II)取代镁铝水滑石中的镁离子(II), 以及将一定量的8-羟基喹啉(8-hydroxyquinoline)分散于镁铝水滑石层间的亲油性阴离子中, 使与其板层表面上的锌离子配位, 经共沉淀法, 合成、组装得到一类迄今未见报道的具高荧光性的类水滑石(Zn-HTLC)荧光材料. 采用荧光光谱、红外光谱、紫外光谱、X射线衍射和热分析等对其进行了表征. 研究表明, 这种类水滑石在紫外光下可发出强烈的蓝绿色荧光(501 nm), 荧光强度高达4.5×10⁵ a.u., 说明锌离子(II)分散于类水滑石的氢氧化镁板层中, 可有效防止发光结构单元的荧光猝灭, 而且溶于层间阴离子中的配体与板层上的锌离子(II)配位所形成的特殊组装结构, 增强了发光中心的不对称性, 也是其具有高荧光性的可能原因. 热分析结果显示, 这种类水滑石耐热性强, 有望应用于各种功能性荧光材料.

Study on the Strong-fluorescent Zn-containing Hydrotalcite-like Compound

A hydrotalcite-like compound in which magnesium(II) was partially substituted by zinc(II) in the hydrotalcite-like layers and 8-hydroxyquinoline was dispersed into the anions in the interlayer region was synthesized by a coprecipitation method. Each Zn^2＋ ion in the layers was coordinated by 8-hydroxyquino- line through the oxygen and nitrogen atoms, making a strong-fluorescent Zn-containing hydrotalcite-like compound (Zn-HTLC) that has never been reported before. The sample has been characterized by X-ray powder diffraction, FT-IR techniques, thermogravimetric analysis, UV/Vis spectrography, fluorescence spectrum, and its composition and structure were determined. It was found that the Zn-HTLC could radiate strong light (501 nm) under ultraviolet radiation, demonstrating that the zinc(II) dispersed in the hydrotalcite-like layers can prevent the fluorescence quenching effect efficiently. The Zn^2＋ ion in the layers was coordinated by the ligand in the interlayer region, forming a special self-assembly structure that may enhance the fluorescence intensity. Otherwise, the result of TG-DSC measurement clearly shows the enhanced thermal stability of the Zn-HTLC compared with that of Mg-Al hydrotalcite. The Zn-HTLC may become a promising candidate for the luminescent functional materials.