Synthesis of Manganese Oxide Clusters with Oxidation Catalysis

我们分别以tacn（1，4，7-三氮杂环壬烷）衍生物和Cp（Cp）为配体合成了Mn-Mo和Rh-W氧化物簇合物。双核草酸盐[（n-Bu_4）N]_2[Mo_2O_7]与（tacn）MnCl_3在水中反应，得到了一种新型立方结构的Mn-Mo混合金属氧化物簇合物[{（tacn）Mn}_2Mo_4O_<16>]-4H_2O（1）。1的X射线分析表明，它是由一个锰（IV），三个钼（VI）离子和四个氧原子组成的立方骨架。研究了1对氯化频哪醇染料（PC染料）漂白的催化性能。在使用1的反应中，染料的蓝色在非均相条件下在水中在6小时内消失：过氧化氢（15摩尔），PC染料（15摩尔）和催化剂（1.5摩尔）。由<16>单核[WO_4]^<2->与[Cp^*RhCl（μ-Cl）]_2在CH_3CN中反应，得到了[（Cp^*Rh）_4W_4O_ ]的两种几何异构体：两种几何异构体均具有风车和三立方烷的几何骨架。前者在20℃以下选择性生成。后者是在60℃以上的同一反应体系中得到的。我们用~ 1H NMR和ESI-MS研究了异构化和异构体形成的机理<17>，发现具有梯形结构的物种在异构化和异构体形成中起着重要作用。

We synthesized Mn-Mo and Rh-W oxide clusters with tacn (1,4,7-triazacyclononane) derivatives and Cp (cyclopentadienyl) ligands, respectively. Their ability of oxidation catalysis for hydrocarbon compounds was examined.A reaction of the dinuclear oxometalate of [(n-Bu_4)N]_2[Mo_2O_7] and (tacn) MnCl_3 in water afforded a new cubic type of the Mn-Mo mixed metal oxide cluster of [{(tacn)Mn}_2Mo_4O_<16>]-4H_2O (1). An X-ray analysis of 1 reveals that it is composed of a cubic framework consisting of one Mn(IV), three Mo (VI) ions and four oxygen atoms. It also has an incomplete cubic framework formed by three Mo (VI) ions and four oxygen atoms.We examined catalytic ability of 1 towards the bleaching of pinacyanol chloride dye (PC dye). In the reaction using 1 the blue color of the dye disappeared in 6h in water under heterogeneous conditions : hydrogen peroxide (15 mol), PC dye (15 mol) and catalyst (1.5 mol). This preliminaly results show that cluster 1 is able to use a mild bleaching catalyst for a heterogeneous system.Rh-W oxide clusters with the Cp^* ligand were prepared in two geometrical isomers of [(Cp^*Rh)_4W_4O_<16>] from the reaction of the mononuclear [WO_4]^<2-> with [Cp^*RhCl(μ-Cl)]_2 in CH_3CN : two geometrical isomers have a windmill and a triple cubane geometrical framework. The former was formed selectively below 20℃. Above 60℃ the latter was obtained specifically in the same reaction system. We studied the mechanisms for the isomerization and the formation of those isomers by using ^<17>O NMR spectroscopy and ESI-MS.It is found that a species with a ladder structure plays an important role for both the isomerization and the formation of the isomers.