The present work shows a new one-stage mechanochemical method for the direct synthesis of alkoxysilanes.

A methodology for synthesizing a wide range of dumbbell‐shaped, graft and bottlebrush polymers with all‐siloxane nature (without carbosilane linkers) is suggested. These macroarchitectures are synthesized from SiOH‐containing compounds—silanol (Et3SiOH) and siloxanol dendrons of the first and second generations, with various peripheral substituents (Me or Et)—and from linear siloxanes comprising terminal and internal SiH groups by the Piers–Rubinsztajn reaction. Products and key building blocks are obtained in yields up to 95%. These polymers are heat and frost‐resistant siloxanes. As it turns out, the product physical properties are determined not only by the macromolecular structure, the linear chain length, the size and frequency of branched pendant, but also by the type of peripheral substituents—Me or Et—in the pendant. Thus, the viscosity of the graft polymers with branched pendant groups comprising peripheral Me‐groups is more than ≈3–5 fold lower than that of analogous polymers with peripheral Et‐groups.

This work presents a solution to one of the most fundamentally and practically important challenges in the production of silica-based aerogels, time consumption and expensiveness of these processes, with the main focus on the sol−gel process. We suggested a highly efficient BF 3 -catalyzed method for the production of aerogels, which allows one to shorten the stage of the formation of a (wet) gel to 5 min, the stage of gel aging to 0, while the stage of gel workup is not required; the duration of these stages, according to the literature, ranges from days to weeks. The process is performed using commercially available, simple, and inexpensive reagents and under mild reaction conditions: BF 3 •Et 2 O as the catalyst, acetone as the solvent, room temperature, and at atmospheric pressure. This approach allows one to quickly obtain both classic opaque and transparent silica-based aerogels from Si(OMe) 4 or Si(OEt) 4 as well as transparent superhydrophobic ones from their mixtures with MeSi(OMe) 3 or Me 2 Si(OMe) 2 . In addition, we succeeded in obtaining a series of aerogels with various organic and inorganic additives, in particular, in this way, luminescent and metallasiloxane ones were prepared. Also, the effect of the method for producing silica-based aerogels on their (supra)molecular structure and morphology was thoroughly studied by a set of physicochemical methods of analysis: scanning electron and light microscopy, X-ray microtomography, and NMR experiments. These findings allow to tune the density, transparency, mechanical strength, hydrophobicity, and other properties depending on the need by choosing the right technique.

Preparation methodology for a series of hydrophobic and amphiphilic well-defined stereoregular cyclic p-tolyl-substituted siloxanes has been proposed.

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Back Cover: In article number 2000645 by Ashot V. Arzumanyan and co‐workers, a methodology for synthesizing dumbbell‐shaped, graft and bottlebrush polymers with all‐siloxane nature is suggested. They are synthesized from different generations and structure dendritic siloxanols and polyhydride‐siloxanes by the Piers–Rubinsztajn reaction. The product physical properties are determined not only by the macromolecular structure, the linear chain length, the size and frequency of branched pendant, but also by the type of peripheral pendant substituents: Me or Et.

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