摘要
近来，自组装超薄膜越来越引起人们的广泛关注，因为它可作为可调控结构的纳米复合膜材料。层接层(LbL)自组装方法，最初产生于一对相反电荷聚电解质的静电吸附，是一种简单而通用的技术，并且具有制备大面积超薄膜的应用潜力。由于制备过程中膜的每一层的厚度、膜间组分的组成都是可控的，LbL技术提供了在分子设计水平上制备多样性有序结构的方法，这一方法在开发各种材料的器件应用上具有明显的优势。
为了探索多金属氧酸盐(简称POMs)阴离子有机官能化的新途径和开发新型的多酸基无机-有机纳米复合膜材料，本文利用层接层(LbL)自组装方法，首次制备出多金属氧酸盐阴离子和重氮树脂(简称DR)的稳定多层复合膜。迄今为止，由多金属氧酸盐和DR制备复合膜并且研究多金属氧酸盐和感光聚合物间发生光诱导反应的工作还未见文献报道。借助于感光聚合物DR在UV光照下容易分解而产生芳环阳离子的特殊性质，然后在UV光照下，有机组分的-N_2~+和多金属氧酸盐阴离子的O-之间的离子键可能转换成共价键，这将大大改善多层膜的结构稳定性。基于上述考虑，我们利用POMs和感光聚合物间的光诱导反应，设计了合理的的稳定多层膜的方法，制备出一系列多金属氧酸盐阴离子和DR合成的稳定的多层膜：(PMo_(12)／DR)n；(PW_(18)／DR)n；(P_2Mo_(18)／DR)n；(Mo_(36)／DR)n，并利用UV-vis；IR；XPS；AFM等方法对所制成的膜进行了表征，获得了一些有价值的基础数据。
此外，多金属钼酸盐阴离子在水溶液中的组成和结构转换是一个富有挑战性的研究课题，其研究结果将对多金属钼酸盐有机官能化反应的设计具有指导意义。已报道的分析结果认为，有[NH_4]_6Mo_7O_(24)·4H_2O、K_6Mo_7O_(24)·4H_2O、Na_6Mo_7O_(24)·4H_2O三种形式能够在水溶液中形成，Raman光谱和~(17)O的核磁共振光谱的分析也为此提供了证据。在本文中，我们初步研究了由七聚体过渡到Mo_8的转换反应机理，考察了抗衡阳离子效应
对多金属铝酸盐阴离子结构稳定性的影响，首次在水溶液中获得八铝
酸四甲基钱盐，测定了它的晶体结构。
The fabrication of self-assembled ultrathin film has recently attracted considerable interest in view of their importance to nanomaterials with tailored structures and properties . The layer-by-layer (LbL) self-assembly method, initially developed for pairs of oppositely charged polyelectrolytes , is a facile and versatile technique that has lately emerged as a viable approach to prepare large area ultrethin films. Because the composition, thickness, and components of each layer in the film can be controlled, the LbL technique provides a route to fabricate various regular structures at the molecule level, which offers potential advantages for device application. Polyoxometalates (POM), a class of molecularly defined inorganic metal-oxide cluster, hold intriguing structures and unexpected properties, and attract increasing attention worldwide .
In addition, a diazo resin can link POMs by electrostatic interactions between the cationic diazonium group (-N2+) and the anionic POMs (O-) in order to form a LbL ultrathin film. Since the photosensitive diazo resin could easily decomposes under UV irradiation, the electrostatic interaction between -N2+ and O- may partly transformed into covalent linkage under UV light [15]. For this consideration, we attempt to enhance the stability of multilayer films by photoinduced interaction between POMs and photosensitive polymers. Here we reported the preparation and characterization of one kind stable multilayer films constructed by polyoxometalates(POMs) and diazo resin.
Polyoxometalates(POMs) are a well-known and significant class of inorganic compounds and currently receiving much attention because of their chemical, structural and electronic versatility and their wide
applications in many fields such as catalysis, medicine,biology,and materials science. Moreover, the syntheses of various polyoxometalate help to obtain new information of intermolecular interaction,which is apparently important for rational design and construction of new framework structures.One of the interesting aspects of octamolybdates, Mo8O264-,is seen in varied structural flexibility in solution. In this paper,we simply studied the reaction mechanism of the transfer of the heptamolybdate into octamolybdate, invested the influence of different cations to the stability of polyoxoanions. We first report the synthesis and crystal structure of [(CH3)4N]4Mo8O26.
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