Cage-like Cu₅Cs₄-Phenylsilsesquioxanes: Synthesis, Supramolecular Structures, and Catalytic Activity

Abstract

A small family of nonanuclear Cu5Cs4-based phenylsilsesquioxanes 1–2 were prepared by a convenient self-assembly approach and characterized by X-ray diffraction studies. The compounds 1 and 2 show some unprecedented structural features such as the presence of a [Ph14Si14O28]14– silsesquioxane ligand and a CuII 5CsI 4 nuclearity in which the metal cations occupy unusual positions within the cluster. Copper ions are “wrapped” into a silsesquioxane matrix, while cesium ions are located in external positions. This resulted in cesium-involved aggregation of coordination polymer structures. Both compounds 1 and 2 realize specific metallocene (cesium–phenyl) linkage between neighboring cages. Compound 2 is evaluated as a catalyst in the Baeyer–Villiger (B-V) oxidation of cyclohexanone and tandem cyclohexane oxidation/B-V oxidation of cyclohexanone with m-chloroperoxybenzoic acid (mCPBA) as an oxidant, in an aqueous acetonitrile medium, and HNO3 as the promoter. A quantitative yield of ε-caprolactone was achieved under conventional heating at 50 °C for 4 h or MW irradiation for 30 min (for cyclohexanone as substrate); 17 and 19% yields of lactone upon MW irradiation at 80 °C for 30 min and heating at 50 °C for 4 h, respectively (for cyclohexane as a substrate), were achieved. Complex 2 was evaluated as a catalyst for the oxidation of alkanes to alkyl hydroperoxides and alcohols to ketones with peroxides at 60 °C in acetonitrile. The maximum yield of cyclohexane oxidation products was 30%. Complex 2 exhibits high activity in the oxidation of alcohols.

A Family of Cagelike Mn-Silsesquioxane/Bathophenanthroline Complexes: Synthesis, Structure, and Catalytic and Antifungal Activity

“…To the best of our knowledge, the current study is the first report on the application of Mn-CLMSs in the synthesis of cyclic carbonates from CO 2 and epoxides. The topic deserves further investigation, namely by alteration of the CLMS metal and of the silsesquioxane ligand …”

Cagelike Manganesesilsesquioxane Complexes: Synthesis via an Acetone Approach, Structure, and Catalytic Activity for Toluene Oxidation

“…CLMSs are widely applied as homo-and heterogeneous catalysts as well as components of catalytic systems. 28,33−39 Among recent reports, CLMSs' activity in (i) deacetalization/deketalization-Knoevenagel reactions, 40 (ii) Chan−Evans−Lam couplings, 41 (iii) Baeyer−Villiger reactions, 42 (iv) CO 2 valorization, 31,43 and (v) carboxylations 44 should be mentioned. Intriguingly, despite detailed investigations of Mn complexes in catalysis, 45,46 the very first example of catalytically active Mn−CLMSs has been reported by some of us very recently for the oxidative amidation conditions.…”

“…A choice of fruitful synthetic solutions for the self-assembly of CLMS complexes remains a challenging task. Numerous articles confirm the opportunity for transformation of simple RSi(OR') 3 reagents into complicated CLMS structures [14][15][16][17][18][20][21][22][23][24][25][26][41][42][43][44]86,87 via the intermediate alkaline hydrolysis stage. 88,89 In this context, recent positive results witnessed a successful approach to a large family (14 examples) of copper-based CLMSs via the use of acetone as a key solvate.…”

“…Among these, CLMSs’ derivatives were investigated in the design of molecular magnets (including examples of single-molecule magnet or spin glass behaviors) − and objects with photophysical properties (e.g., CLMS-based luminescent thermometers). − In turn, several functional coordination polymers, − ceramics, , anodes, , fungicides, and flame retardants were successfully developed on the basis of CLMSs. CLMSs are widely applied as homo- and heterogeneous catalysts as well as components of catalytic systems. ,− Among recent reports, CLMSs’ activity in (i) deacetalization/deketalization-Knoevenagel reactions, (ii) Chan–Evans–Lam couplings, (iii) Baeyer–Villiger reactions, (iv) CO 2 valorization, , and (v) carboxylations should be mentioned. Intriguingly, despite detailed investigations of Mn complexes in catalysis, , the very first example of catalytically active Mn–CLMSs has been reported by some of us very recently for the oxidative amidation conditions .…”

Synthesis of a bistriazolyl-phenanthroline–Cu(ii) complex immobilized on nanomagnetic iron oxide as a novel green catalyst for synthesis of imidazoles via annulation reactions

“…2 The primary goal of process design is to develop highly efficient catalysts for selective and sustainable reactions, improving rates and minimizing by-products. 3–5 Diligent researchers work on identifying novel catalyst materials and exploring innovative synthesis techniques. 6 By harnessing the potential of heterogeneous catalysis, scientists contribute to cleaner, greener, and more resource-efficient chemical processes, building a sustainable and eco-friendly future.…”