烷基紫精/五氧化二钒插层化合物的组装、表征及磁性的研究  

Assembly, Structural Characteristics and Magnetic Property of Alkylviologen/V_2O_5 Intercalation Compounds

作　　者：赖克强[1] 王一蕾[1] 杨帆[1] 孔爱国[1] 丁旵明[1] 单永奎[1] 

机构地区：[1]华东师范大学化学系,上海200062

出　　处：《化学学报》2006年第14期1456-1464,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20273021);上海市科学技术委员会(No.05Jc14070)资助项目.

摘　　要：以烷基紫精(alkylviologens;又称紫精或紫罗精)为有机客体、层状五氧化二钒为无机主体,在液、固两相反应体系中,利用I-与V5+的氧化还原反应,使烷基紫精阳离子通过静电引力作用进入被还原的五氧化二钒层板之间,形成一系列新颖的无机-有机插层化合物.并运用X射线粉末衍射(XRD)、红外(FT-IR)、X射线光电子能谱(XPS)、紫外-可见漫反射(UV-visDRS)等方法对其进行了表征.XRD分析结果证明,五氧化二钒的层间距随着烷基紫精中烷基链的增长而增大,但其结晶度随着烷基紫精阳离子中烷基链的增加而降低.XPS研究表明,该类材料中的钒是以V4+和V5+两种混合价态存在,氧原子处于三种不同的化学环境,这些现象说明烷基紫精阳离子的引入对五氧化二钒的骨架结构影响不大,主体五氧化二钒的层状结构保存完好;氮原子处于两种不同的化学环境,证实插层化合物中主客体之间相互修饰的协同效应,有可能起到了稳定客体分子激发态的作用,同时FT-IR光谱中芳香环特征谱带强度的变化也进一步证明了这一结论.UV-visDRS分析发现由于主客体的相互作用使插层化合物在紫外和可见光区域产生特殊的光吸收性质.从磁性研究的结果可以看出,在温度低于15K时,插层化合物RV2为反铁磁性的有序结构;当温度高于15K时,转变为顺磁性,表现出磁无序结构.In the system of two phases of the liquid and the solid, a novel series of inorganic-organic intercalation compounds were prepared by intercalating alkylviologen cation guest into the layered vanadium pentoxide host with negative charges, which were formed by the redox of I^- and V^5＋, and characterized by XRD, FTIR, XPS and UV-vis DRS. The XRD investigations indicate that the interlayer spacing was increased with the increase of the alkyl chain in the alkylviologen cations and the structural regularity of the intercalation compounds was decreased with the increase of the alkyl chain in the alkylviologen cations. The XPS data show that the phase of vanadium oxides in the intercalation compounds is composed of mixed-valence vanadium oxides, and oxygen atoms are in three different chemical environments. These phenomena indicate that the introduction of alkylviologen cation has little effect on the framework of the V2O5, and the lamenar structure of the V2O5 is basically intact. That nitrogen atoms are in two different chemical environments suggests that the synergic effect of the guest and the host can lead to the stabilization of the excited state of organic guest, which is further confirmed by the intensity change of characteristic bands of aromatic rings in FT-IR spectra. The analysis of UV-vis DRS shows that the intercalation compounds have the absorption character within ultraviolet and visible light region owing to the interaction between such guest and host. The study of the magnetic susceptibility has testified that the intercalation compound was antiferromagnetic with ordered magnetic structure below 15 K. At above 15 K, such compound exhibited paramagnetic behavior and the disordered magnetic structure.

关 键 词：插层化合物 五氧化二钒 烷基紫精 协同效应 主-客体化合物 

分 类 号：O621.25[理学—有机化学]