【作者】 张海军；

【导师】 杨汝栋；

【作者基本信息】 兰州大学 ， 无机化学， 2008， 博士

【摘要】 功能材料成为当今国际上重点开发的领域。本论文以环境友好,简化合成方法以便于实现工业化为目的,以研究和改良材料性能为目标,就我们所感兴趣的稀土配合物荧光材料、锂离子电池材料、以及一些功能材料的纳米化作了探索性研究。本论文的主要内容如下:1.就稀土配合物荧光材料、锂离子电池材料、以及一些功能材料的纳米化的研究进展作了简要的文献综述。2.围绕具有敏化稀土发光的吡啶氮氧化物基团合成了两个新型化合物N,N’-二（2-吡啶氮氧基）吡啶-2,6-二酰胺（H₂L¹）和N,N’-二（2-吡啶-1-氮氧基）-1,2-已二胺（L²）及其稀土配合物,并对这两个配体及其配合物进行了一系列组成及结构表征。对配体H₂L¹与三价稀土离子形成的配合物研究结果表明在不同的合成条件下所得配合物组成不同,同样的合成条件不同的稀土离子形成的配合物组成也略有不同。用H₂L¹与稀土离子直接反应所得的配合物的组成为:Ln（H₂L¹）（NO₃）₃·nH₂O（Ln=Y,Eu,Gd,Tb,n=1;Ln=La,n=2）,配体H₂L¹只提供两个配位点,而其刚性类平面结构由于分子内氢键的作用在配位前后改变很小。而Sc³⁺与H₂L¹直接反应却形成了去质子配合物ScL¹NO₃·2H₂O。对该配合物的单晶结构的表征也证明了我们所推测结构的正确性,同时发现无手性的配合物各个分子之间通过分子间氢键作用进行自组装,形成了具有右手螺旋手性的一维配位超分子链。为此我们用碱调节H₂L¹与除钪外的稀土离子反应溶液的pH值,同样得到了去质子型配合物LnL¹NO₃·nH₂O（Ln=Y,Eu,Gd,Tb,n=1;Ln=La,n=2）。这些去质子配合物中配体均提供五个配位点,配体分子内氢键完全破毁,刚性结构改变较大。对配合物荧光性能的研究发现,这种刚性结构的改变对配体敏化Eu³⁺,Tb³⁺发光有较大影响,未去质子配合物荧光强度均强于相应去质子配合物,其中Tb（H₂L¹）（NO₃）₃·H₂O显示出优异的荧光性能,其荧光强度最强,单色性好。配体L²与三价稀土离子形成的配合物组成为:LnL²（NO₃）₃·H₂O（Ln=Eu,Gd,Tb）。对其荧光性能研究发现Eu和Tb的配合物均有较好的荧光性能,配体能有效的敏化稀土离子发光,且配合物荧光强度较配体未氮氧化时的母体所形成的相应配合物而言,均有所增强。通过配体三重态能级的测定,很好地解释了配合物荧光强度变化的趋势。3.从寻找易于工业化的合成方法和改善材料电化学性能出发,以柠檬酸为络合沉淀剂,首次在有机溶剂中直接优化得到了作为合成锂离子电池正极材料尖晶石型LiMn₂O₄的前驱体LiHMn₂cit₂·2H₂O和合成层状o-LiMnO₂的前驱体LiMncit·H₂O。并通过元素分析、络合滴定、ICP、XRD等对其组成和结构进行了表征。由前驱体LiMncit·H₂O于水中培养得到了单晶Mn₃cit₂·11H₂O,间接的证明了前驱体结构。通过优化煅烧条件得到了纯相正极材料尖晶石型LiMn₂O₄和层状o-LiMnO₂。研究发现在前驱体中柠檬酸有效的络合了Li⁺和Mn²⁺,保证了二者混合的均匀性。同时在烧结时柠檬酸分解产生的物质有效的抑制了正极材料的团聚现象,使其粒径控制在很小的尺寸范围内,为下一步提高材料的电化学性能做好了准备。4.围绕材料纳米化时的尺寸和形貌控制,采用阳离子交换法合成了直径可以从几纳米到几十纳米控制,长度可达几个微米,有望做成纳米器件的Ag₂Te一维纳米线。另外还合成了零维Ag₂Te纳米粒子,以及CdS的零维纳米四面体和一维纳米棒等纳米材料。并就其组成、形貌及性能进行了表征和初步研究。更多还原

【Abstract】 Recently there has been great interesting in studying functional materials.In this dissertation we studied on the rare earth complexes as the luminescence materials,the lithium ion cathode materials,and some other functional nanomaterials.The main content of this dissertation is listed below:First,we reviewed recent research and progress of rare earth luminescence materials,lithium ion cathode materials and some functional nanomaterials.Second,two kinds of new ligands N,N’-di（pyridine N-oxide-2-yl）pyridine-2,6-dicarboxamide （H₂L¹） and N,N’-Bis（2-pyridinecarboxamide-1-N-oxide）-1,2-Ethane （L²） and their corresponding rare earth complexes were synthesized and characterized. It is found that the composition and the structure of the complexes formed by H₂L¹ with rare earth ion change with alternating synthesis condition as well as with different rare earth ion.Direct reaction of H₂L¹ with rare earth ion forms Ln（H₂L¹）（NO₃）₃·nH₂O（Ln = Y,Eu,Gd,Tb,n = 1;Ln = La,n = 2）.The rigid structure of free ligand changes little after coordination because of intramolecular hydrogen bonded interaction.Nevertheless,dehydrogenated complex,ScL¹NO₃·2H₂O, is formed by direct reaction of H₂L¹ with Sc³⁺.We also confirmed its structure by employing X-ray analysis to determine the crystal structure.It’s interesting that each molecule of the complex self-assemble to form right hand helical 1D supermolecular chain by intermolecular hydrogen bonded interaction.Also we succeeded in synthesizing dehydrogenated complexes LnL¹NO₃·nH₂O（Ln = Y,Eu,Gd,Tb,n = 1; Ln = La,n = 2） by adjusting the pH when H₂L¹ reacted with rare earth ion.It is found that the rigid structure of free ligand changed a lot in the as formed complexes.Such a structure change plays an important role on the luminescence properties of the Eu³⁺, Tb³⁺ complexes.The fluorescent intensity of the luminescent non-dehydrogenated complexes is much higher than the corresponding dehydrogenated complexes.While ligand L² forms LnL²（NO₃）₃·H₂O（Ln = Eu,Gd,Tb） with rare earth ion.It is found that as formed Eu and Tb complexes show good luminescence properties.The fluorescent intensity is higher than the corresponding complexes formed by non N-oxide matrix.We also explained the luminescence properties by employing triplet energy level of the ligand.Third,considering simplification of synthesis method and modification of electrochemical properties,we first time synthesized the precursor of LiMn₂O₄, LiHMn₂cit₂·2H₂O and LiMncit·H₂O as the precursor of o-LiMnO₂ in an organic solvent by employing citric acid as a chelating ligand.The structure and composition of each precursor were also characterized by using element analyses,titration,ICP, XRD.Pure phase cathode materials spinel LiMn₂O₄ and layered o-LiMnO₂ were formed by optimizing calcined conditions of precursors.It is found that the decomposed matter of citric acid can restrain effectively the reuniting of as formed cathode material.Fourth,in order to study on the size and shape control of inorganic nanomaterials, semi-conductor Ag2Te nanowires with varied in diameter from several to tens of nanometers and with several micrometers in length were synthesized and characterized.Also we synthesized Ag₂Te nanoparticles as well as CdS nanotetrahedrons and nanorods using high temperature organic phase method.更多还原