Cu42Ge24Na4—A Giant Trimetallic Sesquioxane Cage: Synthesis, Structure, and Catalytic Activity

Abstract

Unprecedented germanium-based sesquioxane exhibits an extremely high nuclearity (Cu42Ge24Na4) and unusual encapsulation features. The compound demonstrated a high catalytic activity in the oxidative amidation of alcohols, with cost-effective catalyst loading down to 400 ppm of copper, and in the oxidation of cyclohexane and other alkanes with H2O2 in acetonitrile in the presence of nitric acid. Selectivity parameters and the mode of dependence of initial cyclohexane oxidation rate on initial concentration of the hydrocarbon indicate that the reaction occurs with the participation of hydroxyl radicals and alkyl hydroperoxides are formed as the main primary product. Alcohols have been transformed into the corresponding ketones by the catalytic oxidation with tert-butyl hydroperoxide.

Cage-like manganesesilsesquioxanes: features of their synthesis, unique structure, and catalytic activity in oxidative amidations

“…Intriguingly, unlike several known examples of phenanthroline-induced supramolecular aggregations provoking extended structures, 70,71,73 stacking interactions in 4 stopped at the dimer stage. This could be compared to a similar effect of dimerization, reported by us, 78 which resulted in the aggregation of metallagermsesquioxane with the record-high nuclearity Cu 42 Ge 24 Na 4 .…”

Oxidation of Organic Compounds with Peroxides Catalyzed by Polynuclear Metal Compounds

“…Such an increase in regioselectivity can be explained by the fact that oxidation in the case of complex 18 occurs in the cavities formed by bulky ligands surrounding the reaction centers of the catalyst molecule. As in the case of iron ions, a large number of works have been devoted to silsesquioxane complexes with copper and their use in catalytic oxidation [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. A few structures of the catalysts used in the most recent years are shown in Figures 12-15.…”

“…Germanium-based sesquioxane copper complex exhibits an extremely high nuclearity (Cu42Ge24Na4) and unusual encapsulation features. This compound is a very active catalyst in the oxidation of al- Not only silsesquioxane complexes, but germsesquioxanes, which are precatalysts in the oxidation of organic compounds, were obtained and described [86][87][88]. An example of structure of such catalysts is given in Figure 15.…”

“…Germanium-based sesquioxane copper complex exhibits an extremely high nuclearity (Cu42Ge24Na4) and unusual encapsulation features. This compound is a very active catalyst in the oxidation of alkanes and alcohols [87]. A recent publication [89] described the synthesis and catalytic properties of complex 21 (see Figure 16).…”

Imidazole-Dependent Assembly of Copper Polymolybdate Frameworks for One-Pot Sulfide Oxidation and C–H Activation

“…The efficient removal of sulfureous compounds and polycyclic aromatic hydrocarbons (PAHs) from petroleum is of great importance and urgent consideration owing to their heavy threat to the atmosphere or human health arising from their combustions. − During the past decades, various removal techniques including adsorption, microbial remediation, photocatalysis, and oxidation have been developed. − Among those methods, oxidation techniques like the sulfide oxidation and C–H oxidation activation for PAHs have been regarded as the most promising technique by virtue of their atom economical, environmentally benign, and commercially viable processes. − Specifically, the resulting carbonyl compounds have been demonstrated as important organic intermediates with a variety of applications in the areas of antibiotics, perfumes, nylon, agrochemicals, and flavor compounds, and these value-added carbonyl compounds can serve as functional fine chemicals in the chemical industry. − Nonetheless, the diverse conditions for the removal of PAHs and sulfurs, along with environmental and economic concerns associated with present techniques, , have sparked research into alternative routes for their simultaneous one-pot oxidation. However, it is seldom reported that two oxidation reactions can be accomplished by a single catalyst under mild conditions and the key challenge to achieve this feasible goal is to develop novel catalysts that enable multifunctional catalysis systems. − …”