【作者】 李强；

【导师】 郭洪猷；

【作者基本信息】 北京化工大学 ， 应用化学， 2005， 博士

【摘要】 多酸化合物是由钒、铌、钽、钼和钨等过渡元素自身或相互间、或与其它元素间所形成的一大类阴离子型“分子态”金属氧化物簇。由于多酸化合物具有纳米范畴的分子尺寸和由d-π轨道和d-π电子所决定的特征电子结构,故表现出奇特的光、电、磁、催化及药理等特性;而有机化合物具有优良的分子裁剪与修饰性能,特别是有机共轭化合物作为新一代的光电材料,其结构和性质易于调控。因此两类化合物的化学结合,由于p-π与d-π轨道的互相作用,可获得性能优异的新材料。特别是由Maatta等人开创的直接亚胺基化法,这样所得到的多酸有机亚胺衍生物,由于有机配体上的氮原子以三键方式与多酸根中的金属原子配位,因而可以使多酸根与有机共轭体系共价键联,导致d-π轨道和p-π轨道间十分强烈的相互作用,而产生更加新颖奇特的物理和化学性能。此外,利用分子剪裁和组装而形成的多酸衍生物可以构造含多酸的网状和树枝状分子系统,从而制备出新型的有机-无机杂化材料。因此,多酸有机亚胺衍生物的合成、结构与性能研究,开发一类具有新奇结构和特异性能的有机-无机杂化材料,将对多酸化学的发展起巨大的推动作用。这无论在理论上还是在应用上都具有重要的意义。 本论文在DCC脱水法的基础上,详细研究多酸衍生物的合成化学,采用各种有机伯胺类化合物及其它含氨基的配体,对Lindqvist结构类型的含钼多酸根及其衍生物进行了化学修饰,进而利用亲核反应进行分子剪裁和组装,制备出新型的有机-无机杂化材料。初步探索其作为催化材料和光、电、磁功能材料的应用。 在Maatta等人开创的直接亚胺基化法的基础上,本论文提出了新的合成方案,即盐酸苯胺盐法。并采用此方案合成了六个新的单取代多酸有机亚胺衍生物（Bu₄N）₂[Mo₆O₁₈（=NR）],式中R为:o-ClC₆H₄,m-ClC₆H₄,p-ClC₆H₄,p-BrC₆H₄,o-CH₃C₆H₄,o-CNC₆H₄。 通过UV-Vis光谱对该合成反应进行监测,提出了最佳的合成条件,即为:采用10mL脱水乙腈为溶剂,于81-84℃回流反应6小时,原料配比为（Bu₄N）₄[α-Mo₈O₂₆]:RNH₂·HCl:DCC=1∶2.0∶3.4。 此外,仅以邻甲苯胺作为合成原料,则合成反应得到邻甲苯胺双取代的六钼酸根有机亚胺衍生物。通过这两种合成方案的对比,提出更多还原

【Abstract】 The early transition metals(V,Nb,Ta,Mo,W) themselves or combining with each others or other elements are able to form molecular metal-oxide cluster anions, commonly referred to as polyoxometalates or polyoxoanions. Those species are remarkable for their important optical, electronic, magnetic, catalytic and medical properties owing to their nanometer-sized shapes and electronic structures involving d-π orbits and d-π electrons. On the other hand, molecular structures of organic compounds are easy to be sheared and modified, particularly, organic conjugated molecules are novel electrically and optically active materials and their molecular structures and properties are also easily controlled. Therefore, the molecular natures of these two types of materials offer the opportunity to generate covalently bonded molecular hybrids where the interaction of delocalized π or p electrons of the organic moiety with d electrons of the cluster may bring exciting synergitic effects and novel materials with excellent properties. Best of all, organoimido derivatives of polyoxometalates with the typical structures of organoimido groups bonded at an octahedral metal center and consistent in a substantial degree of Mo ≡ N triple bond character were synthesized by Maatta’ method. Beside these, an alternative way to efficiently construct novel hybrid molecular materials containing covalently bonded metal-oxygen clusters and organic conjugated segments has also been discovered. In summary, studies on synthesis, structure and properties of organoimido derivatives of polyoxometalates, will promote the development of polyoxometalate chemistry, and also discover a novel kind of organic-inorganic hybrids with novel structures and unusual properties. This is very important in theoryand application.With N,N’-dicyclohexyl-carbodiimide (DCC) as dehydrating agent, the synthesis way of organoimido derivatives of polyoxometalates is studied in detail in this dissertation. Lindqvist hexamolybdates and their derivatives were modified via the reaction of [ a -Mo8O26]4* with aromatic amines or other amines, which are also important building blocks for constructing novel organic-inorganic hybrids based on polyoxometalates by controllable organic synthesis technology such as the nucleophilic reaction, thus a novel kind of organic-inorganic hybrids with novel structures and unusual properties is obtained, which will contribute to be optical, electronic, magnetic, catalytic and medical materials.On the basis of the Maatta’s direct modified method with organoimido, a novel reaction routine to organoimido derivatives of polyoxometalates has been developed, which is the Aromatic Amine halides’ method. And six new organoimido derivatives of polyoxometalates were synthesized via this reaction routine. These six new organoimido derivatives of polyoxometalates can be described with a general chemical formula:(Bu4N)2[Mo6Oi8 (=NR) ].(R=: o-ClQH*, m-ClQsEU, P-CIQH4, p-BrC6H4, 0-CH3QH4, o-CNC6H4).The optimum reaction conditions such as the amount of each raw material and the reaction time can be obtained by monitoring the reaction system with UV-Vis Spectra. In this thesis, by comparing UV-Vis spectroscopy of the product under different conditions, a favorable routine has been obtained and is given in below: A mixture of (Bu4N)4[ a -Mo8O26] (1.0 mmol), Aromatic Amine hydrochloride (RC6H4NH2 ? HC1 2.0 mmol, 1.5 equiv ) and N,N’-dicyclohexyl-carbodiimide (DCC) (3.4 mmol) was refluxed(81-84°C) in anhydrous acetonitrile (10 mL) for about 6h.Moreover, A novel bifunctionalized arylimido derivative of hexamolybdate was synthesized according to the literature procedure where the aromatic amine hydrochloride was not existed in the reaction mixture. By comparison of the synthesis routine of imido and bifunctionalized derivative of [Mo6Oic>]2" with each other, the possible reaction mechanism was suggested. In the novel reaction routine to organoimido derivatives of polyoxometalates, an aromatic amine hydrochloride salt(instead of Yf) is added into the reaction, and contributed to catalyze the reaction, andprevent the side reaction to take place, such as the redox reaction.The structures of these four new organoimido derivatives of polyoxometalates were initially obtained according to X-rays single crystal structure analysis. Most of those compounds crystallized in monoclinic space group P2(l)/n. An important feature that should be pointed out here is the dimerization of cluster anions of these new organoimido derivatives of polyoxometalates in the solid state through the ji - 31 stacking of parallel phenyl rings of two neighboring cluster anions. The existence of k - % interactions between the pairs of cluster anions has not been mentioned up to date. Moreover, the molecular structure of compound (Bu4N)2[Mo6O17 (=NR) 2], (R=o-CH3C6H4, 7) has also been confirmed by single-crystal X-ray diffraction. There is also dimerization of the cluster anions of 7 through k-tl stacking between parallel phenyl rings on two neighboring hexamolybdate cluster anions in the crystal. The existence of the supramolecular n - jt interactions between the pairs of cluster anions is clearly indicated by the short vertical phenyl ring separation of 2.9752A. It is interesting that four such dimers form a supramolecular ring-like structure by linking the dimers with each other via C-H—O hydrogen bonding between a C-H group( C(3)-H(3),0.93A) of one aromatic ring attached to the cluster anion and a terminal oxo group(O(3)) on neighboring cluster anion (C(3)-H(3)—O(3)i, 3.311 A). Such a structural feature has not been mentioned since the phenylimido derivative of hexamolybdate was reported.The composition and structures features of these compounds have also been confirmed by IR and ’H-NMR spectroscopy. The peaks in IR and ] H-NMR spectra of these compounds were also attributed via comparing the corresponding peaks of raw materials. Some factors, such as inductive and conjugative effects, which have an influence on IR and 1 H-NMR spectra of these organoimido derivatives of polyoxometalates, have also been discussed. It is very useful to confirm the compositions and structures of these compounds.The UV-Vis Spectra of these organoimido derivatives of polyoxometalates have been studied in depth, and their characters have also been confirmed. There is a good linear relationship between the shift of UV-Vis absorptions(A A max) and conjugated effect of the p-substituted更多还原