Synthesis of Monofunctionalized Silsesquioxanes (RSiMe2 O)(iBu)7 Si8 O12 via Alkene Hydrosilylation

Organocatalytic synthetic route to esters and their application in hydrosilylation process

A facile esterification of α,β-unsaturated aldehydes with alcohols has been developed for the synthesis of esters by using bulky N-heterocyclic (NHC) carbene as a metal-free and eco-friendly organocatalyst. This new protocol has been proved to be effective with a wide substrate scope, giving selective esters in yields greater than 84% under mild conditions. Moreover, proposed synthetic strategy enables modification of various types of silsesquioxanes (SQ) which cannot or are technically difficult to be carried out with known protocols. For the first time, a one-pot sequential esterification/hydrosilylation has been successfully carried out.

Exploring Polyol-Functionalized Dendrimers with Silsesquioxane Cores

Silsesquioxane dendrimers offer versatile structural potential, prompting our innovative synthesis of G1 and G2 polyol dendritic systems with diverse silsesquioxane cores, ranging from mono-T8 to difunctional and tetrafunctional double-decker silsesquioxanes. Through a strategic combination of hydrosilylation and O-silylation reactions, we have formed an extensive compound library. A major focus was directed toward investigating the reaction conditions of G1.5 dendrimers, as well as evaluating the stability and reactivity of the novel -O-Me2Si-H group. Notably, we unveiled solubility trends of these synthesized dendritic systems in basic organic solvents, offering vital information for potential applications. Our work advances dendrimer research by unraveling intricate synthesis, reactivity, and properties. We contribute to the broader understanding of these organic-inorganic complex interactions and envisage diverse applications in multiple domains.

Distinct insight into the use of difunctional double-decker silsesquioxanes as building blocks for alternating A–B type macromolecular frameworks

A distinct look at known, hydrosilylation reactions used for the formation of DDSQ-based linear A–B alternating macromolecular systems with DPn > 1000 is presented. Selected physicochemical properties of obtained hybrid co-polymers were determined.

Vinyl- and chloromethyl-substituted mono-T8 and double-decker silsesquioxanes as specific cores to low generation dendritic systems

We report the series of G1 and G1.5 dendritic systems with mono-T₈ SQs and DDSQ as specific types of dendron and dendrimer cores, respectively. The trivinyl- and tri(chloromethyl)-derivatives were obtained via hydrolytic condensation followed by the hydrosilylation reaction, optimized to yield selectively β-products. Their structures were confirmed by spectroscopic and XRD analyses. It is the first example of double-decker SQs used as cores for the construction of a low generation of dendrimer featuring specific dumbbell frameworks expanding in two or four directions.

Polysiloxanes Grafted with Mono(alkenyl)Silsesquioxanes-Particular Concept for Their Connection

Herein, a facile and efficient synthetic route to unique hybrid materials containing polysiloxanes and mono(alkyl)silsesquioxanes as their pendant modifiers (T₈@PS) was demonstrated. The idea of this work was to apply the hydrosilylation reaction as a tool for the efficient and selective attachment of mono(alkenyl)substituted silsesquioxanes (differing in the alkenyl chain length, from -vinyl to -dec-9-enyl and types of inert groups iBu, Ph at the inorganic core) onto two polysiloxanes containing various amount of Si-H units. The synthetic protocol, determined and confirmed by FT-IR in situ and NMR analyses, was optimized to ensure complete Si-H consumption along with the avoidance of side-products. A series of 20 new compounds with high yields and complete β-addition selectivity was obtained and characterized by spectroscopic methods.

Pt(0)-Catalysed synthesis of new bifunctional silanes

We report herein very efficient syntheses of new functional silanes obtained via olefin hydrosilylation. New bifunctional compounds contain attractive functional groups such as epoxy, fluoroalkyl, trisilylamine, chloropropyl, and methacroiloxy which can play different roles in molecular systems. Moreover, the catalytic system proposed by us exhibits high selectivity and tolerance to a wide range of functional groups. It also permitted obtaining total conversions of the starting reagents in a relatively short time under mild conditions.

Dialkenylgermanes as Precursors of Silsesquioxane-based Macromolecular Structures

Herein we report a study of highly efficient platinum-catalyzed hydrosilylation of dialkenylgermanes with silsesquioxanes and spherosilicates. The use of divinyl- and diallylgermanes allowed the synthesis of new classes of compounds, i. e., dumbbell-type systems, silsesquioxanes with alkenyl pendant group, and oligomeric derivatives. The results are supported by detailed data from in situ FT-IR and NMR measurements, enabling precise monitoring of the reaction progress and determination of regioselectivity of the formed products.

Introduction of organogermyl functionalities to cage silsesquioxanes

In this work, we present the first example of highly efficient platinum-catalyzed hydrosilylation of vinyl- and allylgermanes with different types of silsesquioxanes and spherosilicates. This protocol allows the straightforward introduction of organogermyl functionalities with alkyl chains linked to the silsesquioxane core with good yields and excellent selectivity. These derivatives may be applied as precursors for the development of advanced hybrid materials in the future. In addition, a comparison made between vinylsilanes and vinylgermanes showed a higher reactivity of germanium compounds in the hydrosilylation reaction. To the best of our knowledge, this is the first literature example of the functionalization of silsesquioxanes and spherosilicates with these types of germanium derivatives. The reaction parameters and kinetics were determined by in situ FT-IR. In addition, our research is supported by extensive data obtained from NMR measurements.

A facile approach for the synthesis of novel silsesquioxanes with mixed functional groups

An efficient pathway for the synthesis of novel organofunctional silsesquioxanes with varied functional groups.

Silica Surface Modification and Its Application in Permanent Link with Nucleic Acids

In this paper, the Pt-catalyzed hydrosilylation of hydroxyl ethers is described. Various bifunctional alkoxysilanes were obtained and applied in O-silylation of free hydroxyl groups on the silica surface. These modified solid materials have been used as excellent supports for linking synthetic nucleic acids. Nucleic acids permanently attached to the solid surface were tested in hybridization with complementary fluorescence-labeled sequences. Detection of nucleic acids anchored to the solid support was performed by fluorescence microscopy after hybridization.

Selective Hydrosilylation of Alkynes with Octaspherosilicate (HSiMe2 O)8 Si8 O12

Comprehensive studies on platinum-catalyzed hydrosilylation of a wide range of terminal and internal alkynes with spherosilicate (HSiMe2 O)8 Si8 O12 (1 a) were performed. The influence of the reaction parameters and the types of reagents and catalysts on the efficiency of the process, which enabled the creation of a versatile and selective method to synthesize olefin octafunctionalized octaspherosilicates, was studied in detail. Within this work, twenty novel 1,2-(E)-disubstituted and 1,1,2-(E)-trisubstituted alkenyl-octaspherosilicates (3 a-m, 6 n-t) were selectively obtained with high yields, and fully characterized (1 H, 13 C, 29 Si NMR, FTIR, MALDI TOF or TOF MS ES+ analysis). Moreover, the molecular structure of the compound (Me3 Si(H)C=C(H)SiMe2 O)8 Si8 O12 (3 a) was determined by X-ray crystallography for the first time. The developed procedures are the first that allow selective hydrosilylation of terminal silyl, germyl, aryl, and alkyl alkynes with 1 a, as well as the direct introduction of sixteen functional groups into the 1 a structure by the hydrosilylation of internal alkynes. This method constituted a powerful tool for the synthesis of hyperbranched compounds with a Si-O based cubic core. The resulting products, owing to their unique structure and physicochemical properties, are considered novel, multifunctional, hybrid, and nanometric building blocks, intended for the synthesis of star-shaped molecules or macromolecules, as well as nanofillers and polymer modifiers. In the presented syntheses, commercially available reagents and catalysts were used, so these methods can be easily repeated, rapidly scaled up, and widely applied.