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Various sectors of the industry are searching for new materials with specific requirements, providing improved properties. The study presents novel composite materials based on polylactide that have been modified with the organosilicon compound, (3-thiopropyl) polysilsesquioxane (SSQ-SH). The SSQ-SH compound is a mixture of cage structures and not fully condensed random structures. The composite materials were obtained through injection moulding. The study includes a comprehensive characterization of the new materials that analyze their functional properties, such as rheology (MFR), mechanical strength (tensile strength, Charpy impact strength), and thermal properties. SEM microscopic photos were also taken to analyze the microstructure of the samples. The addition of a 5% by-weight organosilicon compound to polylactide resulted in a significant increase in MFR by 73.8% compared to the neat polymer. The greatest improvement in impact strength was achieved for the 5% SSQ-SH/PLA composite, increasing it by 32.0 kJ/m2 compared to PLA, which represents an increase of up to 187%. The conducted research confirms the possibility of modifying the properties of the polymer by employing organosilicon compounds. [ABSTRACT FROM AUTHOR]

This study delineates a methodology for the preparation of new composites based on a photocurable urethane-acrylate resin, which has been modified with (3-thiopropyl)polysilsesquioxane (SSQ-SH). The organosilicon compound combines fully enclosed cage structures and incompletely condensed silanols (a mixture of random structures) obtained through the hydrolytic condensation of (3-mercaptopropyl)trimethoxysilane. This process involves a thiol-ene "click" reaction between SSQ-SH and a commercially available resin (Ebecryl 1271®) in the presence of the photoinitiator DMPA, resulting in composites with significantly changed thermal properties. Various tests were conducted, including thermogravimetric analysis (TGA), Fourier transmittance infrared spectroscopy (FT-IR), differential scanning calorimetry (Photo-DSC), and photoreological measurement mechanical property, and water contact angle (WCA) tests. The modification of resin with SSQ-SH increased the temperature of 1% and 5% mass loss compared to the reference (for 50 wt% SSQ-SH, T5% was 310.8 °C, an increase of 20.4 °C). A composition containing 50 wt% of SSQ-SH crosslinked faster than the reference resin, a phenomenon confirmed by photorheological tests. This research highlights the potential of new composite materials in coating applications across diverse industries. The modification of resin with SSQ-SH not only enhances thermal properties but also introduces a host of functional improvements, thereby elevating the performance of the resulting coatings. [ABSTRACT FROM AUTHOR]

Current research on materials engineering focuses mainly on bio-based materials. One of the most frequently studied materials in this group is polylactide (PLA), which is a polymer derived from starch. PLA does not have a negative impact on the natural environment and additionally, it possesses properties comparable to those of industrial polymers. The aim of the work was to investigate the potential of organosilicon compounds as modifiers of the mechanical and rheological properties of PLA, as well as to develop a new method for conducting mechanical property tests through innovative high-throughput technologies. Precise dosing methods were utilized to create PLA/silicone polymer blends with varying mass contents, allowing for continuous characterization of the produced blends. To automate bending tests and achieve comprehensive characterization of the blends, a self-created workstation setup has been used. The tensile properties of selected blend compositions were tested, and their ability to withstand dynamic loads was studied. The blends were characterized through various methods, including rheological (MFI), X-ray (XRD), spectroscopic (FTIR), and thermal properties analysis (TG, DSC, HDT), and they were evaluated using microscopic methods (MO, SEM) to examine their structures. [ABSTRACT FROM AUTHOR]

The reaction of chlorosilanes with organometallic reagents is an old and well‐developed approach to organosilicon compounds, however, its application was limited due to the sensitivity of organometallic reagents to air, water. Here we display a mechanochemical access to arylsilanes via Barbier‐type reaction of chlorosilanes with aryl halide with magnesium. By treatment of the two halides with Mg powder under electromagnetic milling, a series of arylsilanes are obtained within 15 minutes. Taking the advantages of the electromagnetic milling, this protocol features transition‐metal free, good functional group tolerance, air stable and mild conditions. [ABSTRACT FROM AUTHOR]

In this study, organosilicon compounds were used as modifiers of filaments constituting building materials for 3D printing technology. Polymethylhydrosiloxane underwent a hydrosilylation reaction with styrene, octadecene, and vinyltrimethoxysilane to produce new di- or tri-functional derivatives with varying ratios of olefins. These compounds were then mixed with silica and incorporated into the ABS matrix using standard processing methods. The resulting systems exhibited changes in their physicochemical and mechanical characteristics. Several of the obtained composites (e.g., modified with VT:6STYR) had an increase in the contact angle of over 20° resulting in a hydrophobic surface. The addition of modifiers also prevented a decrease in rheological parameters regardless of the amount of filler added. In addition, comprehensive tests of the thermal decomposition of the obtained composites were performed and an attempt was made to precisely characterize the decomposition of ABS using FT-IR and optical microscopy, which allowed us to determine the impact of individual groups on the thermal stability of the system. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed skeletal rearrangement of 2‐(2‐allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5‐C−Pd/C−Si bond exchange. The reaction pathways can be switched toward 4‐membered ring‐forming C(sp2)−H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C−Pd/C−Si bond exchange. [ABSTRACT FROM AUTHOR]

Waterlogged wood conservation is a complex and challenging task. Detailed knowledge about the interactions between the applied chemicals and wood is necessary to ensure the effective and safe conservation of wooden artifacts. The present research aims to determine the mechanism of dimensional stabilization of archeological wood by organosilicon compounds using the combination of synchrotron-based X-ray fluorescence microscopy (XFM) and nanoindentation. Archeological oak wood was treated with methyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, or 1,3-bis-[(diethylamino)-3-(propoxy)propan-2-ol]-1,1,3,3-tetramethyldisiloxane, which in previous studies were found to be more effective than other organosilicons in stabilizing wood dimensions. The XFM and nanoindentation results showed that all three organosilicons infiltrated wood cell walls and enhanced their mechanical properties. The XFM also showed that part of the chemicals filled some void spaces like cell lumina. Based on the results obtained here and in our previous research, it is determined that the mechanism of archeological wood dimensional stabilization by organosilicon treatment is complex and likely involves both filling cell lumina and infiltration into cell walls where organosilicons interact with wood polymers. [ABSTRACT FROM AUTHOR]

Selective dehydrogenative silylation is one of the most valuable tools for synthesizing organosilicon compounds. In this study, a regio- and stereoselective ruthenium-catalyzed dehydrogenative intermolecular silylation was firstly developed to access (E)-alkenyl silyl-ether derivatives and silyl-ether heterocycles with good functional group tolerance. Furthermore, two pathways for RuH2(CO)(PPh3)3/NBE-catalyzed dehydrogenative intermolecular silylation of alcohols and alkenes as well as intermolecular silylation of naphthol derivatives were investigated with H2SiEt2 as the hydrosilane reagent. [ABSTRACT FROM AUTHOR]

Aerogels are a class of materials that have gained increasing attention over the past several decades due to their exceptional physical and chemical properties. These materials are highly porous, with a low density and high surface area, allowing for applications such as insulation, catalysis, and energy storage. However, traditional aerogels, such as pure silica aerogels, suffer from brittleness and fragility, which limit their usefulness in many applications. Herein, we have addressed this problem by using organosilicon compounds, namely polymethylsilsesquioxane derivatives, for the synthesis of aerogel-like materials. Specifically, we have developed a novel approach involving surfactant-free synthesis of microcapsules from partially PEGylated hyperbranched polymethylethoxysiloxane. Due to the highly diphilic nature of these compounds, they readily concentrate at the oil/water interface in aqueous emulsions encapsulating oil droplets. During the subsequent condensation, the organosilicon precursor is consumed for hexane encapsulation (yielding hollow microcapsules) followed by the formation of a continuous condensed phase. Concurrently, methyl groups ensure the hydrophobicity of the resulting materials, which eliminates the need of using additional reagents for their hydrophobization. [ABSTRACT FROM AUTHOR]

ω‐Alkenyltrimethylsilanes of different alkenyl moieties, i.e., 3‐butenyltrimethylsilane, 5‐hexenyltrimethylsilane, and 7‐octenyltrimethylsilane, are used as model compounds to study the alkenyl length effect in copolymerization of ethylene with steric‐hindered tri‐substituted silane‐functionalized α‐olefins over MgCl2/TiCl4 catalysts. The experimental results reveal that 3‐butenyltrimethylsilane tops the three α‐olefins in incorporation rate into PE while 7‐octenyltrimethylsilane is slightly better than 5‐hexenyltrimethylsilane. The coordination‐insertion events for different ω‐alkenyltrimethylsilanes are investigated by DFT simulation. The results suggest that the three ω‐alkenyltrimethylsilanes encounter similar energy barriers during insertion, with similar repulsive interactions between the bulky trimethylsilane substituent and growing PE chain found in the energy decomposition of transition state configuration. However, complexation abilities at the Ti active site for the three ω‐alkenyltrimethylsilanes follow the order of 3‐butenyltrimethylsilane > 5‐hexenyltrimethylsilane > 7‐octenyltrimethylsilane, in line with their molecular compactness, which are deemed to be where the alkenyl length effect originates in the ω‐alkenyltrimethylsilane/ethylene copolymerization. [ABSTRACT FROM AUTHOR]

Hot-melt adhesives (HMAs) are thermoplastic materials that can bond various substrates by solidifying rapidly upon cooling from the molten state, and their modification with organosilicon compounds can result in crosslinking behavior, characteristic of gels. Organosilicon compounds are hybrid molecules that have both inorganic and organic components and can enhance the properties and performance of HMAs. The gel aspect of HMA with and without organosilicon modifiers can be considered in organosilicon-modified systems, the modifiers are often either sol–gel condensation products or their mechanism of action on the adherent surface can be considered of sol–gel type. The purpose of this manuscript is to present the current state of the art on the formulation, characterization, and application of HMAs and optimize their performance with organosilicon compounds for application in various industries such as automotive, construction, and photovoltaics. This review covers articles published within the period of 2018–2022. The article is divided into sections, in which information about hot-melt adhesives is described at the beginning. The following part of the presented review focuses on the composition of hot-melt adhesives, which takes into account the use of organosilicon compounds. The last part of this review outlines the future trends in hot-melt adhesives. [ABSTRACT FROM AUTHOR]

Catalytic enantioselective intermolecular C−H silylation offers an efficient approach for the rapid construction of chiral organosilicon compounds, but remains a significant challenge. Herein, a new type of chiral silyl ligand is developed, which enables the first iridium‐catalyzed atroposelective intermolecular C−H silylation reaction of 2‐arylisoquinolines. This protocol features mild reaction conditions, high atom economy, and remarkable yield with excellent stereoselectivity (up to 99 % yield, 99 % ee), delivering enantioenriched axially chiral silane platform molecules with facile convertibility. Key to the success of this unprecedented transformation relies on a novel chiral PSiSi‐ligand, which facilitates the intermolecular C−H silylation process with perfect chem‐, regio‐ and stereo‐control via a multi‐coordinated silyl iridium complex. [ABSTRACT FROM AUTHOR]

Catalytic enantioselective intermolecular C−H silylation offers an efficient approach for the rapid construction of chiral organosilicon compounds, but remains a significant challenge. Herein, a new type of chiral silyl ligand is developed, which enables the first iridium‐catalyzed atroposelective intermolecular C−H silylation reaction of 2‐arylisoquinolines. This protocol features mild reaction conditions, high atom economy, and remarkable yield with excellent stereoselectivity (up to 99 % yield, 99 % ee), delivering enantioenriched axially chiral silane platform molecules with facile convertibility. Key to the success of this unprecedented transformation relies on a novel chiral PSiSi‐ligand, which facilitates the intermolecular C−H silylation process with perfect chem‐, regio‐ and stereo‐control via a multi‐coordinated silyl iridium complex. [ABSTRACT FROM AUTHOR]

We use the Clayton and Frank copulas and the exponentiated odd log-logistic family to define a new flexible bivariate model to fit bimodal and asymmetry data. The copulas allow different distributions for the response variable, thus making analysis more suitable. We present some structural properties of the new model and describe a simulation study to show the consistency of the estimators. We construct a bivariate regression model based on the new family to fit oak lettuce plant data for different concentrations of silicon dioxide and organosilicon compounds. We check the response variables fresh weight and plant height together in order to verify the existing correlation between them. These variables exhibit a bimodal form, and the family used is able to model this behavior. Different marginal distributions are selected, which is an interesting point of the copula methodology. The variables have strong positive dependence, and the experiment is carried out comparing the control treatment with others leading to the following results: (i) the treatment 1-ethoxysilatrane (with concentrations 5 × 10 − 4 mL·L − 1 and 10 − 3 mL·L − 1 ) is not significant for the response variables; (ii) the treatment amorphous silicon dioxide (with concentrations 50 mg·L − 1 and 100 mg·L − 1 ) and the same treatment (with concentrations 5 × 10 − 3 mL·L − 1 and 10 − 2 mL·L − 1 ) are significant and have positive effects on both responses; (iii) the treatment amorphous silicon dioxide (with concentrations 200 mg·L − 1 and 300 mg·L − 1 ) are significant and have negative effects on the response variables. Overall, the proposed bivariate model is suitable for the current data and can be useful in other applications. [ABSTRACT FROM AUTHOR]

Acylsilanes are an important class of organosilicon compounds that have gained increased attention recently. Their various reaction modes in particularly their ability to generate carbenes under thermal or photochemical conditions render them valuable reagents in organic synthesis. In this communication, an unprecedented route towards acylsilanes is reported by introducing the acylsilane moiety directly in a single step through alkene hydrosilylation. In this context, acylhydrosilanes representing a novel class of acylsilanes are introduced and applied as silylation reagents in rhodium catalyzed alkene hydrosilylations to access a great variety of acylsilanes. These reactions occur in good to excellent yields under mild conditions and show high functional group tolerance and atom economy. [ABSTRACT FROM AUTHOR]

Background: Monochorionic (MC) twins present a higher incidence of unfavorable clinical perinatal outcomes than dichorionic (DC) twins, often in association with placental vascular anastomosis. In this study, we profiled the umbilical cord plasma metabolomes of uncomplicated MC and DC twin pregnancies and related these to several offspring outcomes, previously associated with birthweight. Methods: Umbilical vein blood samples were collected at birth from 25 pairs of uncomplicated MC twins and 24 pairs of uncomplicated DC twins. The samples were subjected to gas chromatography-mass spectrometry-based metabolomics. 152 metabolites were identified from the cord plasma samples of MC and DC twins. Partial least squares discriminant analysis and pathway analysis were performed to compare within DC/MC twin pairs and between DC and MC twins. A generalized estimating equation (GEE) model was utilized to explore the correlation between metabolic differences and birthweight discordance within and between twin pairs. Results: Our study revealed clear differences between the metabolite profiles of umbilical cord plasma of MC and DC twins. Metabolite profiles in MC within twin pairs and DC within twin pairs were characterized by the differences in 2 − hydroxyglutaramic acid levels and nicotinamide levels, respectively. The metabolic pathways of GSH, tryptophan, and fatty acid metabolism, were significantly downregulated in MC twins compared to DC twins. In addition, the concentration of caffeine and decamethyl-cyclopentasiloxane (D5) was positively correlated with birthweight in MC and DC twins. Conclusion: This study demonstrated that the altered metabolites in umbilical plasma made contributions to the different chorionicities between uncomplicated MC twins and DC twins. The chorionicity of twins seems to affect the metabolic cross-talk between co-twin pairs and be related to birthweight discordance of twins. [ABSTRACT FROM AUTHOR]

This article presents the results of investigations on heterophase polymerization of vinyl monomers in the presence of organosilicon compounds of different structures. On the basis of the detailed study of the kinetic and topochemical regularities of the heterophase polymerization of vinyl monomers, the conditions for the synthesis of polymer suspensions with a narrow particle-size distribution using a one-step method have been determined. [ABSTRACT FROM AUTHOR]

The activation of Si-H bonds and/or Si-Si bonds in organosilicon compounds by transition-metal species plays a crucial role for the production of functional organosilicon compounds. Although group-10-metal species are frequently used to activate Si-H and/or Si-Si bonds, so far, systematic investigation to clarify the preferences of these metal species with respect to the activation of Si-H and/or Si-Si bonds remain elusive. Here, we report that platinum(0) species that bear isocyanide or N-heterocyclic-carbene (NHC) ligands selectively activates the terminal Si-H bonds of the linear tetrasilane Ph2(H)SiSiPh2SiPh2Si(H)Ph2 in a stepwise manner, whereby the Si-Si bonds remain intact. In contrast, analogous palladium(0) species are preferably inserted into the Si-Si bonds of the same linear tetrasilane, whereby the terminal Si-H bonds remain intact. Substitution of the terminal hydride groups in Ph2(H)SiSiPh2SiPh2Si(H)Ph2 with chloride groups leads to the insertion of platinum(0) isocyanide into all Si-Si bonds to afford an unprecedented zig-zag Pt4 cluster. Group 10 metal species are commonly used to activate Si–H and Si–Si bonds, but their preferred reactivity towards Si–H vs Si–Si activation is poorly understood. Here, Pt(0) species are shown to selectively activate the Si–H bonds in a linear tetrasilane, whereas Pd(0) preferentially activates the Si–Si bonds. [ABSTRACT FROM AUTHOR]

Changes in the composition and physicochemical properties of porous monolithic 3D nanostructures of aluminum oxyhydroxides (porous monolithic aluminum oxides, PMAO) chemically modified in methyltrimethoxysilane vapors have been studied by thermal-analysis methods. The conditions of formation and compositions of organosilicon compounds on the PMAO surface have been determined, a high degree of hydrolysis (91%) of the alkoxy groups of the modifier during chemisorption has been confirmed. The dependence of the composition of the porous nanocomposite structure (Al2O3–SiO2) on the conditions of chemical and thermal treatment has been investigated. General changes in the chemical composition of the nanocomposite when using different annealing times in the range from 100 to 1200°C has been described. [ABSTRACT FROM AUTHOR]

[Display omitted] New N -isopropyl- N' , N' -diphenyl- N -(silylmethyl)ureas were obtained, and their structure was explored by 1H, 13C, 29Si NMR spectroscopy and X-ray analysis. These results have shown that N -isopropyl- N' , N' -diphenyl- N -[(fluorosilyl)-methyl]ureas exist as (O–Si) chelates with intramolecular dative bond C=O→Si. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed C(sp2)–H silylation of morpholinones to afford silyl morpholinones is reported. The native secondary amine, which is tolerated in the reaction, is able to promote the C–H activation and silylation of the aryl group. The substrates are monosilylated selectively and tolerate various functional groups. The resulting silyl morpholinone derivatives are potentially useful in pharmaceuticals and agrochemicals. [ABSTRACT FROM AUTHOR]

The readily available cyclobutadiene platinum complex [(C4Et4)PtCl2] catalyzes hydrosilylation of alkenes and alkynes. The reaction typically proceeds at room temperature and does not require any solvent. The target products are obtained from both terminal and internal alkynes, as well as from terminal alkenes in 43–99% yields. The scope of silanes includes various tertiary silanes (Et3SiH, (EtO)3SiH, Ph3SiH) and the disubstituted silane Ph2SiH2. The hydrosilylation proceeds with typical anti‐Markovnikov regioselectivity giving mainly β(E)‐vinylsilanes from alkynes and linear alkyl silanes from alkenes. [ABSTRACT FROM AUTHOR]

Anti-icing coatings have provided a very good alternative to current, uneconomic, active deicing methods, and their use would bring a number of significant benefits to many industries, such as aviation and energy. Some of the most promising icephobic surfaces are those with hydrophobic properties. However, the relationship between hydrophobicity and low ice adhesion is not yet clearly defined. In this work, chemical modification of an epoxy gelcoat with chemical modifiers from the group of double organofunctionalized polysiloxanes (generally called multifunctionalized organosilicon compounds (MFSCs)) was applied. The anti-icing properties of manufactured coatings were determined by means of measurements of shear strength between the ice layer and the modified surface, conducted using a tensile machine. In the work, tests were also performed on the roughness, wettability, and durability of the properties in an aging chamber. It was found that the performed modifications of the coating's chemical composition by the addition of polysiloxanes enabled us to reduce ice adhesion by 51% and to increase the water contact angle by 14% in comparison to the neat gelcoat. A reduction in ice adhesion was also observed with the increasing water contact angle and with decreasing surface roughness. In addition, only one modification recorded an increase in ice adhesion after exposure in the aging chamber. [ABSTRACT FROM AUTHOR]

Hydroxyalkyl-functionalized organosilicon compounds have been prepared from hydrogen-containing organosilicon compounds by hydrosilylation. Various carboxyalkyl-modified organosilicon compounds were then prepared by reacting the hydroxyalkyl-functionalized organosilicon compounds with various cyclic acid anhydrides under solvent and catalyst free. The effects of the nature of the hydroxyalkyl functional groups and the structure of the organosilicon compounds on the ring-opening reaction have been investigated. The synthesized carboxyalkyl-modified organosilicon compounds have been used to treat cotton fabric samples, and the effects of their structures on the softness, whiteness, breaking strength, hydrophilicity, and fiber surface morphology of the cotton have been studied. [ABSTRACT FROM AUTHOR]

In this work, we synthesized some organosilicon derivatives of piroxicam. Due to some properties of organosilicon compounds, including increased lipophilicity and thermal stabilization and prodrug for drugs, some silyl ethers of this drug were synthesized and characterized. Increasing of the lipophilic properties of this drug can be very important in the rate of absorption and its effectiveness. We synthesized silyl ethers of this drug, in the next step some copolymers this drug was synthesized. All of compounds were identified by spectroscopic methods. [ABSTRACT FROM AUTHOR]

In this study, the influence of TiO2 pigment filler modified with spherosilicate derivatives on the processes and thermomechanical properties of composites based on PLA was investigated. Rheological tests (MFR) were carried out, on the basis of which it was found that the addition of organosilicon compounds has a plasticizing effect on the polymer-filler systems. TGA and DSC analysis were performed. The analysis of the contact angle showed that 1.5% of the additives had an influence on the superhydrophobic properties of TiO2 (above 135°), and a slight improvement of this parameter was also observed for composites containing the modified pigment. Microscopic analysis and mechanical tests (tensile strength, impact strength and flexural strength tests) were carried out as well. It has been observed that the addition of certain derivatives adversely affects the dispersion of the filler, thus a slight improvement in mechanical properties is observed. For modifiers that do not affect filler agglomeration, a plasticizing effect on the composite is observed. [ABSTRACT FROM AUTHOR]

The main known patterns of thermal and/or catalytic destruction of high-molecular-weight organosilicon compounds are considered from the viewpoint of the prospects for processing their wastes. The advantages of using supercritical fluids in plastic recycling are outlined. They are related to a high diffusion rate, efficient extraction of degradation products, the dependence of solvent properties on pressure and temperature, etc. A promising area for further research is described concerning the application of supercritical fluids for processing the wastes of organosilicon macromolecular compounds. [ABSTRACT FROM AUTHOR]

A Cu-catalyzed cascade reaction of four-membered silacyclobutanes (SCBs) and thiosulfonates to construct S (Se)-containing organosilicon compounds was developed. The protocol shows a wide range of substrate scope, high functional group compatibility and mild reaction conditions. New C–S (Se) and Si–O bonds were constructed in one step. [ABSTRACT FROM AUTHOR]

A novel NiH-catalyzed highly regioselective coupling of alkenes with vinyl chlorosilanes, constructing C–Si bonds, is developed. Under mild reaction conditions, a series of benzyl organosilanes with various functional groups could be accessed. Further synthetic studies illustrate that the products of this chemistry could be used as versatile precursors to prepare complicated organosilicon compounds. Moreover, the NiH-catalyzed mechanism of the present transformation was proposed based on control experiments. [ABSTRACT FROM AUTHOR]

Organosilicon varnishes, such as polymethylphenylsiloxane and polyaluminomethylphenylsiloxane, filled with modified clay minerals are the object of research. The most vulnerable place of the organosilicon coating is insufficient mechanical properties (hardness, impact strength, etc.) and low adhesive strength of the film to the surface, especially when operating at elevated temperatures. Various oxides, ceramic compounds, natural and synthetic silicate materials are introduced into organosilicon compositions to improve the specified properties. But only individual units can comprehensively improve both the mechanical and heat-resistant properties of organosilicon compounds although the range of such materials is quite wide. The clay minerals palygorskite, which is classified as an intermediate type between strip and layered silicates, and montmorillonite from the subclass of layered silicates, which have a natural high dispersion, were used as fillers during the study. The choice of palygorskite and montmorillonite is explained by the sufficient study of their behavior in organic environments by a number of scientists, availability and economic advantages for introduction into production. Existing clay minerals, which are traditionally used to solve the problem of improving the physical and mechanical properties of organosilicon coatings, are not sufficiently active due to the hydrophilic properties of the particles surface. Based on this, a modifier that has proven itself well in this field was used for the study. A number of compositions of heat-resistant organosilicon varnishes with modified fillers based on the abovementioned clay minerals were obtained. It was established that the introduction of modified forms of natural aluminosilicates contributes to the increase of temperature resistance in filled coatings, compared to coatings made of pure polymer. At the same time, the best effect is achieved when using montmorillonite. This is related with the fact that the proposed compositions of polymethylphenylsiloxane varnish and montmorillonite have a number of features, in particular, the highest comprehensive result of simultaneous improvement of the physical, mechanical and thermal properties of the specified coatings. It is possible to obtain compositions with stable physico-mechanical properties, as they withstood heat treatment at 400 °C for 100 hours without visible changes in integrity, due to the introduction of the optimal amount of modified montmorillonite into organosilicon varnishes KO-08K and KO-921. Compared to similar heat-resistant polymethylphenylsiloxane varnishes, longer service life at elevated temperatures is ensured. [ABSTRACT FROM AUTHOR]

The article presents an in‐depth study of the applicability of cooperative [M]‐/Organo‐catalytic systems in aerobic Si−H‐functionalization. A thorough kinetic study allowed us to identify two "complementary" catalytic systems based on earth‐abundant [M]‐catalysts and inexpensive commercially available organic catalysts. The first system, Co(OAc)2/N‐hydroxysuccinimide, made it possible to oxidize a Si−H‐group to a Si−OH‐group in a wide range of monomers, including previously unknown ones, that dramatically differ in their reactivity. However, this system failed in the case of oligomeric and polymeric substrates. This problem was solved by application of the Cu(OAc)2/N‐hydroxyphthalimide system. A wide potential for gram‐scale (50–100 g) preparation of Si−OH‐containing products with molecular architectures of different complexity was revealed using the established "substrate‐reactivity‐catalytic system" relationship. In particular, previously unknown types of dumbbell‐shaped and graft polymers were synthesized using alkoxysilanols. [ABSTRACT FROM AUTHOR]

The effectiveness of protective coatings based on 3-(2,2,3,3,4,4,5,5-octafluoropentyloxy)propyltriethoxysilane (OFTES) in protecting concrete surfaces against water was tested. For the synthesis of OFTES, 2,2,3,3,4,4,5,5-octafluoropentanol, which is a by-product in the synthesis of poly(tetrafluoroethylene), was used. The proposed silane is a cheaper alternative to the fluorinated organosilicon compounds currently used. The coatings were deposited by the sol-gel method. As a result of the creation of chemical bonds between the concrete surface and the silane, a coating was created that permanently increases the hydrophobicity of the concrete. Fluorine chains attached to silicon atoms are an effective barrier that prevents access to water and limits its impact on the concrete surface. As a result of the proposed silanization, the concrete surface obtained a hydrophobic character at contact angles of up to 126°, and the water absorption of the concrete decreased by up to 96%. [ABSTRACT FROM AUTHOR]

Despite growing progress in the construction of chiral organosilicon compounds, the catalytic asymmetric synthesis of silicon‐stereogenic silanols is less explored and remains a considerable challenge. Herein, we report the first enantioselective construction of silicon‐stereogenic silanols by the catalytic asymmetric hydrolytic oxidation of dihydrosilanes. This practical procedure features ambient reaction conditions, high atom economy, good functional‐group compatibility, and H2 as the only by‐product, and produces a wide range of valuable chiral silanols and bis‐silanols in decent yields with excellent chemo‐ and stereoselectivity. [ABSTRACT FROM AUTHOR]

This review presents the main achievements in the use of the thiol-ene reaction in the chemistry of silicones. Works are considered, starting from monomers and ending with materials.The main advantages and disadvantages of this reaction are demonstrated using various examples. A critical analysis of the use of this reaction is made in comparison with the hydrosilylation reaction. [ABSTRACT FROM AUTHOR]

Despite growing progress in the construction of chiral organosilicon compounds, the catalytic asymmetric synthesis of silicon‐stereogenic silanols is less explored and remains a considerable challenge. Herein, we report the first enantioselective construction of silicon‐stereogenic silanols by the catalytic asymmetric hydrolytic oxidation of dihydrosilanes. This practical procedure features ambient reaction conditions, high atom economy, good functional‐group compatibility, and H2 as the only by‐product, and produces a wide range of valuable chiral silanols and bis‐silanols in decent yields with excellent chemo‐ and stereoselectivity. [ABSTRACT FROM AUTHOR]

The work is devoted to studying the properties of polydimethylsiloxane rubber crosslinked with MQ copolymer and modified with organosilicon compounds of different architectures: asymmetric stereoregular organosilicon stars with flexible siloxane arms and organosilicon nanogel. The statistics of crystallization of water droplets on polydimethylsiloxane-rubber-based coatings has been investigated at temperatures of –15 and –20°С. It has been shown that the coatings are hydrophobic and exhibit anti-icing properties. At –15°С, the droplets on the surfaces of these coatings may remain in a metastable supercooled state for up to 30 hours. At –20°С, the time of droplet crystallization is reduced to 30 min. Under isothermal low-temperature conditions, the positive effect of the modifiers incorporated into polydimethylsiloxane rubber crosslinked with MQ copolymer manifests itself as a decreased rate of droplet crystallization on the coatings containing 1 wt % nanogel or organosilicon stars with flexible siloxane arms as compared with that on the initial polymer. [ABSTRACT FROM AUTHOR]

Three events occurred in the second half of 1946 in three adjoining US States (NJ, NY, and PA) which marked the birth of Hydrosilylation Technology. They occurred before the landmark 1957 JACS paper and the 1958 issued US patent by Speier et al. and before Chalk and Harrod named the reaction. First, on 27 June 1946, Mackenzie et al., of Montclair Research Corp., applied for a patent to prepare addition compounds of hydridosilanes and unsaturated organic compounds. Then, on 9 October 1946, Wagner and Strother of Union Carbide Corp. applied for a patent on a process to produce organic compounds of silicon with Si–C bonds by reacting a hydridosilane and an alkene or alkyne in the presence of a catalyst metal of the platinum group. Finally, Sommer et al., submitted a paper on peroxide-catalyzed hydrosilylation to JACS on 17 December 1946. It was published in January 1947. The landmark patent interference § and priority § case law associated with the Mackenzie et al. and Wagner et al., applications is well known to patent attorneys. This presentation will retrace the origins of hydrosilylation and report events (1946–1960) in the history of the reaction that are most probably unknown to most authors and presenters of hydrosilylation investigations. George Wagner's contribution to the birth of this technology is also highlighted. [ABSTRACT FROM AUTHOR]

The effect of modifying epoxy polymers with organosilicon compounds and curing with agents containing aminophenol groups on their thermal stability was studied. It was shown that the NPPN-638 epoxy-navolac resin is characterized by the highest thermal stability (50% weight loss thereof is achieved at 440°C, while that of the ED-20 epoxy-diane resin is at 365°C). It was found that all the modifiers used, and especially the SILRES MSE 100 polysiloxane, significantly enhance the heat resistance of the NPPN-638 epoxy pillowcase polymer, shifting the temperature corresponding to a 50% weight loss by 200°C to higher temperatures. ED-20 epoxy oligomer-based compositions modified with Phobe 1500N polyorganosilane were produced, the crosslinking of which with Cardolite NC-558 and NC-552 phenalamines makes it possible to yield composites with long-term stability in the temperature range of 350–450°C. Compositions based on the hybrid binder SILIKOPON EC : NPPN-631 reinforced with mineral powders were developed, and coatings with heat resistance in an oxidizing environment in the range of 700–1000°C were produced, which are of interest for use in the aviation and space industries. [ABSTRACT FROM AUTHOR]

Silica is an important inorganic compound used in many materials, including quartz products and resin fillers. To synthesize silica by a dry process, combustion methods using organosilicon compounds as raw monomers have been extensively studied. However, few studies have considered mass production or compared preparation methods using different types of organosilicon compounds and the same equipment. In this study, we used six starting materials in a dry process and examined the effect of monomer species on particle shape and size. The amount of raw monomer supplied was adjusted so that the calorific value of combustion was the same for all the raw monomers. We focused on the calorific value because it affects the construction cost of industrial‐scale production plants. For example, when the calorific value is high, the manufacturing plant is large and costly because the heat generated after the reaction must be removed. We obtained spherical silica particles by a dry process using six monomers. The particle size depended on both the basic unit of the monomer and the required oxygen (RO) ratio of the primary burner gas. This combination was essential in determining the speed of the initial reaction, number of nuclei, and residence time. Consequently, we established a factor that determines the size of spherical silica particles and successfully adjusted the particle size. [ABSTRACT FROM AUTHOR]

[Display omitted] The metallation of CH-groups in carboranyl polyhedra with n -butyllithium followed by end-capping with chloro(di-methyl)vinylsilane was explored using a model B -substituted organosilicon derivative obtained previously, the optimal conditions being Et 2 O, –10 →20 °C, total processing time 125 min. This procedure was applied to prepare a zero-generation polyfunctional B -substituted carborane-carbo-silane dendrimer G 0 -4 cages. [ABSTRACT FROM AUTHOR]

A series of mono- and polyfunctional carborane organosilicon derivatives were prepared with good yields based on the hydrosilylation reactions of allylcarboranes with hydride-containing organosilicon compounds such as tetramethyldisiloxane, decamethylpentasiloxane and triethoxysilane in the presence of Karstedt's catalyst. The functionalization of the double bonds in the allylcarboranes proceeded regioselectively in accordance with the Farmer's rule, providing efficient access to carborane silicon compounds. It was found for 9-o- and 9-m-allylcarboranes that an excess of Karstedt's catalyst could promote the migration of a double bond in allylcarboranes to form boron-substituted propenyl derivatives; the structure of the ortho-isomer was supported by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

This review considers the key advantages of using supercritical carbon dioxide as a solvent for systems with organosilicon compounds. Organosilicon polymeric materials synthesis as well as the creation and modification of composites based on them are discussed. Polydimethylsiloxane and analogues used as polymerization stabilizers and nucleation promoters in pore formation processes are analyzed as well. [ABSTRACT FROM AUTHOR]

Some organosilicon compounds, including alkoxysilanes and siloxanes, proved effective in stabilizing the dimensions of waterlogged archaeological wood during drying, which is essential in the conservation process of ancient artifacts. However, it was difficult to determine a strong correlation between the wood stabilizing effect and the properties of organosilicon compounds, such as molecular weight and size, weight percent gain, and the presence of other potentially reactive groups. Therefore, to better understand the mechanism behind the stabilization effectiveness, the reactivity of organosilicons with wood polymers was studied using a 2D 1H–13C solution-state NMR technique. The results showed an extensive modification of lignin through its demethoxylation and decarbonylation and also the absence of the native cellulose anomeric peak in siloxane-treated wood. The most substantial reactivity between wood polymers and organosilicon was observed with the (3-mercaptopropyl)trimethoxysilane treatment, showing complete removal of lignin side chains, the lowest syringyl/guaiacyl ratio, depolymerization of cellulose and xylan, and reactivity with the C6 primary hydroxyls in cellulose. This may explain the outstanding stabilizing effectiveness of this silane and supports the conclusion that extensive chemical interactions are essential in this process. It also indicates the vital role of a mercapto group in wood stabilization by organosilicons. This 2D NMR technique sheds new light on the chemical mechanisms involved in organosilicon consolidation of wood and reveals what chemical characteristics are essential in developing future conservation treatments. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) were synthesized by microwave irradiation, the corresponding technology was substantiated, and the properties and structure of the resultant CNTs were examined. The process flow diagram of the synthesis was described, and the microwave irradiation regimes for the catalytic systems based on ferrocenes (C10H10Fe) were substantiated. Information about the morphological features of the synthesized CNTs was derived and analyzed using transmission electron microscopy, as well as Raman spectroscopy and differential scanning calorimetry methods. Considering great importance of CNTs in the modification of organosilicon matrices, studies on modification of polymers with the use of the synthesized CNTs were carried out. The uniformity of distribution of the CNTs in the polymer matrix was estimated, and the thermal conductivity of the organosilicon compound at different CNTs concentrations was investigated. The thermal conductivity was found to change from 0.2 to 0.32 W/(m °C), when the CNTs concentration is varied from 1 to 7%. [ABSTRACT FROM AUTHOR]

The impact of three different organosilicon compounds: poly(dimethylsiloxane) (PDMS), potassium methylsiliconate (MESI) and triethoxyoctylsilane (OTES), used as integral admixtures, on Portland cement hydration has been investigated by isothermal calorimetry and DTA-TG analysis. The silicon-based compounds are widely used as internal hydrophobic agents added into batch water; therefore, their effectiveness was investigated by means of capillary water absorption test. The isothermal calorimetry was used to measure the rate and amount of heat released during ordinary Portland cement hydration with integral organosilicon admixtures at 20 °C, 30 °C, 40 °C and 50 °C. It allowed to determine the activation energy as well. The results indicate that used admixtures (except MESI admixture) decrease in the rate and amount of heat release during cement hydration. In addition, it is noticeable that the addition of MESI admixture significantly prolongs the induction period and delays hydration. In contrast to MESI and OTES admixtures, PDMS-based admixture does not affect significant on the activation energy. DTA-TG analysis had shown differences between reference sample and samples containing organosilicon admixtures during thermal decomposition, in terms of the amount of moisture and bound water, as well as Ca(OH)2 or carbonates. The results presented in this paper enable a better understanding of the interactions between the organosilicon integral admixtures and the cement matrix. The study shows the effect of integral admixtures on cement hydration and thus the potential effect on the final properties of the cement-based material. [ABSTRACT FROM AUTHOR]

We have developed a palladium‐catalyzed addition of a C−Si bond of acylsilanes across a range of unactivated allenes. The reaction proceeds with complete regioselectivity, in which a silyl group binds to the central carbon of the allene, allowing for the straightforward access to functionalized alkenylsilane derivatives. [ABSTRACT FROM AUTHOR]

We have developed a palladium‐catalyzed addition of a C−Si bond of acylsilanes across a range of unactivated allenes. The reaction proceeds with complete regioselectivity, in which a silyl group binds to the central carbon of the allene, allowing for the straightforward access to functionalized alkenylsilane derivatives. [ABSTRACT FROM AUTHOR]

Organosilicon compounds are widely used in materials science, medicinal chemistry and synthetic chemistry. Recently, significant progress has been achieved in transition metal‐catalyzed dehydrogenative C−H silylation. Particularly, recently developed monohydrosilane and dihydrosilane mediated C−H silylation have emerged as powerful tools in constructing C−Si bonds. Besides, dihydrosilane‐mediated enantioselective asymmetric C−H silylation has successfully enabled the construction of central and helical silicon chirality. In addition, chiral organosilicon compounds have exhibited excellent photoelectric material properties and broad application prospects. Furthermore, organosilicon compounds could under a series of functional group transformations to enrich the diversity of silicon chemistry. This review will present a comprehensive picture of the development of transition metal‐catalyzed hydrosilane‐mediated intramolecular C(sp2)−H and C(sp3)−H silylation organized by their reaction types and mechanisms. In addition, dihydrosilane‐mediated enantioselective asymmetric C−H silylation to construct central and helical silicon chirality will also be highlighted in the review. [ABSTRACT FROM AUTHOR]

In recent years, transition-metal-catalyzed enantioselective C–H bond functionalization has emerged as a powerful and attractive synthetic approach to access silicon-stereogenic centers, which provides impetus for the innovation of chiral organosilicon chemistry. This short review summarizes recent advances in the construction of silicon-stereogenic silanes via transition-metal-catalyzed enantioselective C–H functionalization. We endeavor to highlight the great potential of this methodology and hope that this review will shed light on new perspectives and inspire further research in this emerging area. 1 Introduction 2 Enantioselective C–H Functionalization Induced by Oxidative Addition- of an Aryl-OTf Bond 3 Enantioselective C–H Functionalization Induced by Oxidative Addition- of a Silacyclobutane 4 Directing-Group-Assisted Enantioselective C–H Functionalization 5 Enantioselective Dehydrogenative C–H/Si–H Coupling 5.1 Enantioselective C(sp2)–H Silylation 5.2 Enantioselective C(sp3)–H Silylation 6 Summary and Outlook [ABSTRACT FROM AUTHOR]