Eugenol-containing oligoorganosilsesquioxanes were synthesized by the method of hydrolytic polycondensation in an active medium under various reaction conditions. The obtained products were characterized by 29Si NMR spectroscopy and MALDI-TOF spectrometry. It was shown that factors such as the reaction temperature, polycondensation duration, and molar ratio between the initial alkoxysilane monomer and acetic acid may affect the molecular weight characteristics and molecular structure of the formed oligomer, like the content of stressed cyclic units (T3, DTT, TDT) and unstressed silsesquioxane units TnDm. In particular, an increase in the ratio of the initial reagents led to an increase in the content of silsesquioxane Tn fragments from 28.2%mol to 41.7%mol, while the number of strained cyclic structures decreased by more than two times. An increase in the synthesis time is of no particular practical value since it was found that the composition of the oligomers synthesized for 6 h and 12 h was practically identical, as was that of the oligomers synthesized for 24 h and 48 h. A noticeable transition in the oligomer composition was observed only when the synthesis time was changed from 12 h to 24 h. Finally, it was shown that the choice of synthesis temperature had the strongest effect on the oligomer composition. The oligomer synthesized at 95 °C contained the highest amount of silsesquioxane Tn fragments, >77%mol, while a Tn fragment content of ~42%mol was observed during the synthesis at 117 °C. It was shown that silsesquioxanes are devitrified at room temperature (Tg from −6.4 to −10.6 °C), and their thermal stability in an inert atmosphere is 300 °C. The synthesized oligomers, due to the presence of hydroxyl-containing eugenol units, may be promising binders and additives for functional epoxy–silicone paints and coating materials.

Modern research in the field of synthesis of organofunctional oligosilsesquioxanes is considered. Relationships between the composition and structure of oligomeric organosilsesquioxanes and the conditions for their formation during the hydrolytic and acidohydrolytic polycondensation of organotrialkoxysilanes containing various functionalities, such as methacrylic, aminopropyl, carboxyl, and cyclotriphosphazene groups, in organic radicals bonded to silicon atoms are shown. A comparative analysis of approaches to the synthesis of organofunctional incompletely condensed oligosilsesquioxanes has been carried out.

The influence of the phase state of the reaction system and the HCl concentration during hydrolytic polycondensation of methyltrichlorosilane on the composition of the formed oligomers, their stability during storage and ability to thermal curing is shown. The technological production process is developed and the scheme of a pilot plant for obtaining oligomethylsilsesquioxanes used for the production of highly filled thermo- and fire-resistant polymer composite materials is presented.

Phosphazenes are a well-studied class of organometallic compounds with perspective characteristics, already tested in various applications. However, until now, three-dimensionally crosslinked structures based on them are primarily obtained by irradiation (that is UV and Cobalt-60). It is generally accepted that such processes proceed via the mechanism of the cleavage of C-H bonds present in the organic substituents, which clearly indicates the lack of selectivity and the impossibility to control the crosslinking degree and distribution. Within this article, multifunctional organosubstituted structures based on the short-chain penta-functional trichlorophosphazodichlorophosphonyl with eugenol and methacrylic fragments were obtained. All products were characterized by1H and31P NMR spectroscopy and MALDI-TOF mass spectrometry. The tendency of compounds with linear methacrylic substituents to undergo the phosphazene-phosphazane rearrangement, so that the dominant reaction product turns to the tetrasubstituted derivative, has been shown. All the obtained compounds can be used as the independent monomers to obtain rigid hybrid organo-inorganic matrices, as well as polyfunctional crosslinking agents for various polymers.

Despite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a given size and for the controlled cyclization reaction when it is secondary and undesirable. We synthesized a series of short linear phosphazene oligomers with the general formula Cl[PCl2=N]n–PCl3+PCl6– and studied their tendency to form cyclic structures under the influence of elevated temperatures or in the presence of nitrogen-containing agents, such as hexamethyldisilazane (HMDS) or ammonium chloride. It was established that linear oligophosphazenes are inert when heated in the absence of the mentioned cyclization agents, and the formation of cyclic products occurs only when these agents are involved in the process. The ability to obtain the desired size phosphazene cycle from corresponding linear chains is shown for the first time. Known obstacles, such as side interaction with the PCl6– counterion and a tendency of longer chains to undergo crosslinking elongation instead of cyclization are still relevant, and ways to overcome them are being discussed.

Amino-containing oligosilsesquioxanes are synthesized by the hydrolytic polycondensation of 3‑aminopropyltriethoxysilane and its cocondensation with phenyltrimethoxysilane in ethanol. According to 1H and 29Si NMR spectroscopy, the oligomers contain incomplete cyclochain structures along with ladder fragments. It is suggested that the spontaneous gelation of the oligomers during long-term storage is due to the intermolecular interactions of siloxane chains with silanol and aminopropyl groups.

According to 1H, 13C, and 29Si NMR spectroscopy, in the hydrolytic copolycondensation of 3‑aminopropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane, side reactions of addition of amine groups to methacrylate groups (the Michael reaction), as well as partial hydrolysis and transesterification of ester bonds, occur along with the main process of the formation of oligomeric silsesquioxanes. Depending on the ratio of the starting alkoxysilanes, the oligomers are soluble in water (excess of 3-aminopropyltriethoxysilane) or in organic solvents (excess of 3-methacryloxypropyltrimethoxysilane). Mixed oligomers are capable of gelation at room temperature; the duration of the process increases and the content of the gel fraction decreases with an increase in the proportion of 3-methacryloxypropyltrimethoxysilane units in the oligomer molecules.

Methacrylate-containing silsesquioxane–siloxane oligomers with M w = (2–20) × 10 3 determined by gel permeation chromatography (GPC) are synthesized by acidohydrolytic copolycondensation of γ‑methacryloxypropyltrimethoxysilane and diorganodialkoxysilanes. According to the data of 29 Si NMR spectro-scopy, the molecules of these oligomers contain silsesquioxane units (RSiO 1.5 ) n , where R is a γ-methacryloxypropyl radical, and mixed cyclic structures of the (RSiO 1.5 ) m (R'R''SiO) p type, where R' is CH 3 and R'' is CH 3 or C 6 H 5 , with linear diorganosiloxane fragments added to them. The introduction of 6 wt % silsesquioxane–siloxane oligomers into a filled base dental compound based on a mixture of bismethacrylates increases its mechanical characteristics by more than a factor of 1.25–1.75 with a simultaneous substantial decrease in the polymerization shrinkage, water uptake, and water solubility.

Imidophosphoric organic esters containing phosphoryl groups are potential polydentate ligands and promising extractants of rare-earth elements. For their preparation, a monophosphazene salt [PCl3=N−PCl3]+[PCl6]− and short phosphazene oligomers of the general formula [Cl–(PCl2=N)n–PCl3]+[PCl6]−, where n = 4–7, were synthesized via living cationic polymerization of Cl3P=NSiMe3 and used as starting compounds. All phosphazenes were reacted with 2-ethylhexanol to obtain the corresponding esters of imidophosphoric acids (EIPAs). The formation of imidophosphoric acids occurs due to the phosphazene-phosphazane rearrangement of –P(OR)2=N– or –P(OH)(OR)=N– units, where R = 2-ethylhexyl. The prepared EIPAs were characterized by 1H, 31P NMR, and MALDI-TOF analyses and their extractive capacity towards lanthanide ions in aqueous solutions of nitric acid was examined. The EIPAs are mixtures of mono-, di-, and trifunctional compounds of the type HxA, where x = 1–3, which can form chelate complexes of lanthanide ions [Ln(A)z], where z = 3–6, depending on the chain length. The longer chain EIPAs are more suitable for collective rare-earth elements extraction. A comparison of the extraction properties of the EIPAs with the industrially used polyalkylphosphonitrilic acid (PAPNA) was drawn.

Methacrylate-containing oligosilsesquioxanes were synthesized by acidohydrolytic copolycondensation of γ-methacryloyloxypropyltrimethoxysilane and phenyltrimethoxysilane in a mixture of bismethacrylate monomers, 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)phenyl]propane and triethylene glycol dimethacrylate, and were characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Performing the process in the bismethacrylate medium favors formation of uniform blends. Their introduction in an amount of 3 wt % into filled methacrylate dental composites considerably improves the physicomechanical characteristics of these composites.

Methacrylate-containing oligosilsesquioxanes with a molecular mass of 700–4000 are synthesized via the acidic hydrolytic polycondensation of γ-methacryloxy-propyltrimethoxysilane (A-174) in the medium of methyl methacrylate or in a mixture of bis(methacrylates). The structure of the oligomers is studied by 1Н and 29Si NMR spectroscopy and MALDI-TOF mass spectrometry.

A new route to a high molecular weight polyphosphazene precursor, phosphoranimine, Cl3PNSiMe3, via the interaction between PCl5 and HN(SiMe3)2 is described. The effects of process temperature and initial reagents ratio are discussed. The synthesis is performed heterogeneously, without a preliminary dissolution of PCl5.

Triethoxysilylphosphazenes have been synthesized via hydrosilylation of cyclotriphosphazenes with various contents of 4-allyl-2-methoxyphenoxy groups by triethoxysilane at an equimolar phosphazene–silane ratio. Hydrolytic copolycondensation of the latter compounds with ?-methacryloxypropyltrimethoxysilane resulted in oligosiloxanes involving functional methacrylic and phosphazene fragments. The oligomers have been used as additives to a dental composition based on bisphenol A-diglycidyl methacrylate and triethylene glycol dimethacrylate. The modified filled compositions are characterized by reduced (4-fold) sensitivity to external illumination and improved strength properties and microhardness.

Methyl acrylate oligosilsesquioxanes based on γ-methacryloxypropyltrimethoxysilane and its mixtures with phenyltrimethoxysilane have been synthesized through acidohydrolytic polycondensation and studied via NMR spectroscopy and MALDI-TOF mass spectrometry. It is shown that the addition of the aforementioned oligosilsesquioxanes to a dental composition based on 2,2-bis[ p -(3-metacryloyloxy-2-hydroxypropoxy)phenyl]propane and triethylene glycol dimethacrylate improves the mechanical characteristics of cured polymer composites.

Методом ацидогидролитической поликонденсации синтезированы и с помощью ЯМР-спектроскопии и масс-спектрометрии MALDI-TOF исследованы метакрилатсодержащие олигосилсесквиоксаны на основе -метакрилоксипропилтриметоксисилана и его смесей с фенилтриметоксисиланом. Добавки указанных олигосилсесквиоксанов в стоматологическую композицию на основе 2,2-бис-[n-(3-метакрилоилокси-2-гидроксипропокси)фенил]пропана и диметакрилата триэтиленгликоля улучшают физико-механические характеристики отвержденного полимерного композита.