【作者】 刘建才；

【导师】 廉世勋；

【作者基本信息】 湖南师范大学 ， 有机化学， 2007， 硕士

【摘要】 将阳光中的紫外光和绿光转换成蓝光和红光是提高植物光合作用的一种途径。添加光致发光材料的农用塑料薄膜称之为转光膜。转光膜具有光转换功能，并能够有效地促进植物的生长。水滑石因其特殊的层状结构和化学组成而具有选择性红外吸收功能。所以，它已经被当作一种新型的塑料助剂，用于农膜增加保温效果。普通水滑石不具有发光性能，若在水滑石的层板或层间引入发光离子或基团，则有望成为一种同时具有选择性红外吸收和发光性质的双功能农膜添加助剂。稀土元素由于其独特的4f层电子结构，具有良好的光电磁性质，近年来逐渐成为光电磁等新型功能材料的重要掺杂元素。因此，我们立意在水滑石中引入稀土离子或稀土配合物，研究具有选择性红外吸收性能和转光性能的有机—无机杂化材料。本学位论文设计了两条合成路线：（1）利用水滑石层板阳离子的同晶取代性将稀土Eu³⁺掺入水滑石层板，然后再利用水滑石层间阴离子的可交换性将有机配体插层进入水滑石层间，敏化稀土离子的发光，得到无机-有机杂化的层状材料。（2）先合成可插层组装的稀土有机配合物，以MgAl-NO₃ LDHs为前体采用离子交换法将稀土配合物插层组装进入水滑石层间，得到另一种无机-有机杂化的层状材料。主要内容如下：1．层板掺铕镁铝类水滑石的制备和性质采用共沉淀法水热合成了稀土铕掺杂的镁铝类水滑石层状化合物（MgAlEuCO₃-LDHs）。探讨了溶液pH值、组分配比和陈化时间、温度对水滑石晶体结构的影响。控制体系的合成条件可得到结晶好、纯度高的镁铝铕类水滑石；MgAlEuCO₃-LDHs保持了水滑石的层状结构，在600～1350 cm^-1有红外吸收；荧光光谱测试发现掺杂稀土Eu³⁺离子的MgAlEuCO₃-LDHs具有Eu³⁺的⁵D₀→⁷F_J特征光谱。Eu³⁺成功地插层组装进入LDHs层板，MgAlEuCO₃-LDHs化合物是一种具有选择性红外吸收和红色发光性质的双功能材料。2．有机配体阴离子插层镁铝铕类水滑石的制备和发光性质通过离子交换法，以硝酸根型的镁铝铕类水滑石为前体，制备了结晶度高的苯甲酸、对苯二甲酸、水杨酸和吡啶-2，6-二羧酸插层柱撑的镁铝铕类水滑石。稀土铕离子和有机配体阴离子分别进入水滑石层板和层间，保持了良好的水滑石层状结构，增加了水滑石在中红外区域的吸收；有机配体阴离子的插入，增加了材料的发光效率，获得了典型的稀土铕离子的红色发光，尤以吡啶-2，6-二羧酸插层水滑石发光效果最好。通过XRD和FT-IR的表征结果，结合理论计算有机配体阴离子的电荷布居，建立了有机阴离子插层柱撑镁铝铕类水滑石的超分子结构模型，并初步探讨了材料的发光机理。3．铕配合物插层柱撑镁铝类水滑石的合成与性质我们通过离子交换法在水热条件下成功的制备了铕配合物插层镁铝类水滑石（MgAl-Eu（DPA）₃LDHs）。稀土铕配合物作为整体插层进入水滑石层间，保持良好的层状结构，分析表明Eu（DPA）₃^3-采取C3轴垂直于层板方式定向在层间。由于在层间引入了有机配体，所以插层后的水滑石也增加了在1100～1600 cm^-1的红外吸收，MgAl-Eu（DPA）₃LDHs保持了高效Eu³⁺的特征红色发光，与纯稀土铕配合物相比，其荧光强度增强。更多还原

【Abstract】 A possible way to increase the photosynthetic effective of plants is toconvert the ultraviolet （UV） and green （G） component in sunlight intoblue （B） and red （R）. The plastic farm film containing specialphotoluminescent materials is called light-conversion farm film, whichcan considerably increase the growth of plants.Layered double hydroxides （LDHs） have selectivity absorption ofinfrared light owing to their special layers structure and chemicalcomposition. So, LDHs have been used as a new additive in the plasticfarm film to enhance temperature of greenhouse. However, the commonLDHs don’t have luminescent properties. But novel layered doublehydroxide （LDH） phases containing rare earth （RE） have been preparedby ion-exchange method using complexes as guest anions. It issuggestion that it is possible to synthesis a novel dual-function additivesfor plastics farm film with selectivity absorbing infrared wavelength andlight conversion function by ion exchange or intercalation method in thebase of LDHs.Rare earths have better optical, electronic and magnetic propertiesdue to their distinctive 4f shell electronic structure. So, the aim of ourinvestigation focuses on the synthesis inorganic/organic hybrid materialswith dual-functional by the method of intercalation the rare earth or rareearth ligand into LDHs structure.In this thesis, in order to getting dual-functional LDHs materials,two strategies are designed. （1） First, Al³⁺ cations within LDHs layerswere replacement of Eu³⁺ by using the isomorphous substitution; then intercalation of organic anions intercalate into LDHs interlayer by theion-exchange method, to enhance the luminescence of LDHs doped withEu³⁺ ions. （2） The rare earth complexes were prepared; it was intercalatedinto MgAl-NO₃ LDHs precursor by ion-exchange method. The details areas follow:1. Preparation and luminescence of LDHs doped with Eu³⁺ ionsThe samples of MgAl-hydrotalcites containing Eu³⁺ （MgAlEu-CO₃LDHs） were prepared by co-precipition and through hydrothermaltreatment. Various preparative factors such as system pH value, content,aging time and temperature, were studies. Through controlling thereaction condition, the results of product may give rise to high purity andbetter crystal form of MgAlEu-CO₃ LDHs. MgAlEu-CO₃ LDHs hold thelayered structure and have infrared absorption at 600～1350 cm^-1. Underexcitation by 399 nm, there are three sharp emissions peaked at 594, 620and 700 nm in emission spectrum of MgAlEu-CO₃ LDHs, which belongto the ⁵D₀→⁷F_J（J=1,2,4） transition of Eu³⁺ ion. Besides, the luminescentintensity changed with the increasing of Eu³⁺/Al³⁺ molar ratio. All ofresults revealed that a few Al³⁺ ions within layers of LDHs were replacedby Eu³⁺ ions in our sample. It was found that the MgAlEu-CO₃ LDHs is anovel dual-function material with selectivity absorbing infraredwavelength and red emitting.2. Preparation and luminescence of Eu-LDHs intercalated organiciigandBenzoate, terephthalte, salicylate and pyridine-2,6-dicarboxylic（DPA）were intercalated into the interlayer MgAlEu-NO₃ LDHs precursor byion-exchange method. It is still good layered structure and infrared absorption. At the same time, organic anions intercalation LDHs enhancethe relative intensity of red luminescent of Eu³⁺ ion.Pyfidine-2,6-dicarboxylic （DPA） Pillared MgAlEu-LDHs have the bestluminescence in above hybrid materials. The samples thus obtained werecharacterized by XRD and FT-IR, then combining the mulliken chargedensity of organic guest anions using an ab initio（HF/6-31G） method byGaussian 03w, the supermolecule structure model of organic guest anionsintercalated MgAlEu-LDHs were build, and its luminescent mechanismwas also discussed.3. Synthesis and properties of europium ligand intercalation in LDHsHaving been prepared, Eu（DPA）₃^3- complex was intercalated into theinterlayer of MgAl-NO₃ LDHs by ion-exchange method throughhydrothermal treatment （MgAl-Eu（DPA）₃ LDHs）. The analyses indicatedthat Eu（DPA）₃^3- complex as an entirety intercalated into LDHs interlayerspace, and Eu（DPA）₃^3- molecules steadily arranged with C3 axisperpendicular to the layer plane. The luminescence studies showed thatMgAl-Eu（DPA）₃ LDHs have keeping typical red luminescence of Eu³⁺ion and exhibits enhanced red luminescence compared with those of purepowder samples.更多还原