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Ladder-like structured poly(phenyl-co-glycidoxypropyl) silsesquioxanes with different ratios of phenyl to glycidyl group (LPS64 and LPS 82) were synthesized using simple hydrolysis reaction followed by condensation polymerization of phenyltrimethoxysilane (PTMS) and (3-glycidyloxypropyl)trimethoxysilane (GPTMS). Two series of hybrid polyimide composites (PI/LPS64 and PI/LPS82) with different contents of LPS (10, 20, and 30 wt%) were prepared by the chemical reaction of epoxy groups in LPS64 or LPS82 and the terminal amine groups in poly(amic acid). The dielectric constant (k) of hybrid PI composites (k = 1.3) was lower than that of pure polyimide (k = 2.9) and the degree of roughness was increased according to the increase of LPS contents. The dispersion of LPS in the PI matrix was improved due to the chemical bonding between LPS and PI. The thermal stability of PI/LPS82 was higher than that of PI/LPS64 due to the enhanced π-π stacking between PI matrix and LPS82 with more phenyl groups as compared to LPS64. [ABSTRACT FROM AUTHOR]

The synthesis of the phosphorus‐capped heptaphenylsilsesquioxane T7Ph7P is reported. We show that, unlike previous examples, it readily forms Lewis acid‐base adducts with boranes of different steric demand and the FeCO4 fragment. All complexes were characterized by multinuclear NMR and IR spectroscopy in solution and the solid state. The molecular structures of the adducts with BPh3 and B(C6F5)3 were determined from XRD suitable single crystals. The relative conformation of the Ph and C6F5 rings in T7Ph7P−B(C6F5)3 suggests favorable π‐interactions, stabilizing the adducts to such a degree that attempts to activate H2 or CO2 were unsuccessful. [ABSTRACT FROM AUTHOR]

Silsesquioxanes (SQs) are mostly used to provide high‐temperature electrical insulation of resins. Here, SQ is used to functionalize unsaturated polyester (UPE) varnish and investigate the effect of functionalization on the thermal and electrical properties of UPE varnishes. The solvent‐free varnish incorporates a reactive diluent to decrease viscosity and a catalyst to expedite hardening, eliminating the need for solvents. Vinyl toluene (VT) and 1,4‐butanediol dimethacrylate (BDDMA) serve as hardening agents, consistent with prior research. Various characterization tests, including Fourier transform infrared, thermogravimetric analyzer, assessment of thermal conductivity coefficient, and determination of electrical volume–surface resistance, are conducted to determine the physical, thermal, chemical, and electrical properties of the synthesized SQ‐functionalized UPE (UPES) varnishes. Results indicate that the UPES–BDDMA varnish demonstrates the highest thermal decomposition temperature at 438.0 °C, while the UPES–VT varnish exhibits the highest electrical volume resistance of 2.85 × 1015 Ω cm. Volatile organic compound levels in UPE coatings range between 4.9% and 5.10% reflecting the growing demand for eco‐friendly products. It is shown in this study that the use of BDDMA and VT reactive monomers in the synthesis of SQ‐functionalized UPE resin and the properties of the resulting varnishes, especially electrical insulation and thermal stability, are improved. [ABSTRACT FROM AUTHOR]

The efficient and straightforward NHC‐rhodium‐catalyzed thiol‐silane and thiol‐germanane coupling reactions, leading to new classes of functionalized SQ‐based materials, are presented for the first time. The proposed strategies use commercially available reagents and show a broad functional groups tolerance, which opens a possibility of effective synthetic procedures of biologically active compounds. [ABSTRACT FROM AUTHOR]

We report the synthesis and single-crystal X-ray diffraction, magnetic, and luminescence measurements of a novel family of luminescent cage-like tetranuclear silsesquioxanes (PhSiO15)8(LnO15)4(O)(C5H8O2)6(EtOH)2(CH3CN)2-2CH3CN (where Ln = Tb, 1; Tb/Eu, 2; and Gd, 3), featuring seven-coordinated lanthanide ions arranged in a one-capped trigonal prism geometry. Compounds 1 and 2 exhibit characteristic Tb[sup 3+] and Tb[sup 3+]/Eu[sup 3+]-related emissions, respectively, sensitized by the chelating antenna acetylacetonate (acac) ligands upon excitation in the UV and visible spectral regions. Compound 3 is used to assess the energies of the triplet states of the acac ligand. For compound 1, theoretical calculations on the intramolecular energy transfer and multiphonon rates indicate a thermal balance between the [sup 5]D4 Stark components, while the mixed Tb[sup 3+]/Eu[sup 3+] analog 2, with a Tb:Eu ratio of 3:1, showcases intra-cluster Tb[sup 3+]-to-Eu[sup 3+] energy transfer, calculated theoretically as a function of temperature. By utilizing the intensity ratio between the [sup 5]D4^[sup 7]F5 (Tb[sup 3+]) and [sup 5]D0^[sup 7]F2 (Eu[sup 3+]) transitions in the range 11-373 K, we demonstrate the realization of a ratiometric luminescent thermometer with compound 2, operating in the range 11-373 K with a maximum relative sensitivity of 2.0% K[sup -1] at 373 K. These findings highlight the potential of cage-like silsesquioxanes as versatile materials for optical sensing-enabled applications. [ABSTRACT FROM AUTHOR]

As part of this research, new halogen free organosilicon compounds were synthesized for the modification of natural fabrics. Difunctional polysiloxanes containing alkoxysilyl groups and silsesquioxane moieties in their structure were obtained by hydrosilylation or thiol-ene click reaction. Using two different reactions leading to the formation of polysiloxane derivatives, we demonstrate the influence of the chemical structure of the obtained polymers on the properties of modified cotton. The structure of the synthesized compounds was confirmed by FT-IR and NMR spectroscopy. After the synthesis of 6 different polysiloxane derivatives with different content of functional groups in their structures, they were applied to the natural fabrics in order to render them hydrophobic. The samples were modified via the dip-coating process. As a result of the research, superhydrophobic fabrics were obtained that are completely resistant to the process of repeated washing. The water repellency of the fabrics was assessed by measuring the water contact angle. The presence of the modifier on the fiber surface (before and after washing) was confirmed by FT-IR and SEM–EDS analysis. In addition, the surface of the modified fibers was examined using SEM images. [ABSTRACT FROM AUTHOR]

While smaller polyhedral oligomeric silsesquioxanes TnRn (POSS) are readily accessible or even commercially available, unambiguously authenticated larger systems (n>12) have barely been reported. Synthesis and isolation procedures are lengthy, and yields are often very low. Herein, we present the surprisingly straightforward and high‐yielding access to the phenyl‐substituted derivative of a so far only postulated second D3h‐symmetric T14 isomer and with that the largest crystallographically characterized POSS cage with organic substituents. Treatment of the commercially available incompletely condensed T7Ph7(OH)3 silsesquioxane with catalytic amounts of trifluoromethanesulfonic acid results in high yields of the T14Ph14 framework, which is isolated in crystalline form by a simple work‐up. D3h‐T14Ph14 was analyzed by single crystal X‐ray diffraction, multinuclear NMR spectroscopy and thermal analysis. The relative energies of all four theoretically possible T14Ph14 isomers were determined by optimization of the corresponding structure using DFT methods. [ABSTRACT FROM AUTHOR]

While smaller polyhedral oligomeric silsesquioxanes TnRn (POSS) are readily accessible or even commercially available, unambiguously authenticated larger systems (n>12) have barely been reported. Synthesis and isolation procedures are lengthy, and yields are often very low. Herein, we present the surprisingly straightforward and high‐yielding access to the phenyl‐substituted derivative of a so far only postulated second D3h‐symmetric T14 isomer and with that the largest crystallographically characterized POSS cage with organic substituents. Treatment of the commercially available incompletely condensed T7Ph7(OH)3 silsesquioxane with catalytic amounts of trifluoromethanesulfonic acid results in high yields of the T14Ph14 framework, which is isolated in crystalline form by a simple work‐up. D3h‐T14Ph14 was analyzed by single crystal X‐ray diffraction, multinuclear NMR spectroscopy and thermal analysis. The relative energies of all four theoretically possible T14Ph14 isomers were determined by optimization of the corresponding structure using DFT methods. [ABSTRACT FROM AUTHOR]

The bicyclic silicon(I) ring compound Si4{N(SiMe3)Mes}4 (2) was used as starting material in reactions with chalcogens and chalcogen transfer agents at low temperatures. This resulted in the selective formation of new cage compounds. With Me3NO, a silicon oxide with adamantane‐type cage 3 was isolated that represents the first isolated T4 silsesquioxane. Reactions with propylenesulfide and red selenium gave direct access to defect heterocubane‐type cages 4 and 5 with three Si−Si bonds wherein the silicon atoms adopt different low oxidation states of +I and +III. A reaction with elemental tellurium even occurs below room temperature to provide ditelluro−tetrasila−tricyclohexane 6. [ABSTRACT FROM AUTHOR]

The bicyclic silicon(I) ring compound Si4{N(SiMe3)Mes}4 (2) was used as starting material in reactions with chalcogens and chalcogen transfer agents at low temperatures. This resulted in the selective formation of new cage compounds. With Me3NO, a silicon oxide with adamantane‐type cage 3 was isolated that represents the first isolated T4 silsesquioxane. Reactions with propylenesulfide and red selenium gave direct access to defect heterocubane‐type cages 4 and 5 with three Si−Si bonds wherein the silicon atoms adopt different low oxidation states of +I and +III. A reaction with elemental tellurium even occurs below room temperature to provide ditelluro−tetrasila−tricyclohexane 6. [ABSTRACT FROM AUTHOR]

Polytitaniumorganosilsesquioxanes were synthesized by the hydrolysis of triethoxysilanes with octyl and vinyl groups followed by the reaction with tetrabutoxytitanium and studied. [ABSTRACT FROM AUTHOR]

We report the synthesis and single-crystal X-ray diffraction, magnetic, and luminescence measurements of a novel family of luminescent cage-like tetranuclear silsesquioxanes (PhSiO1.5)8(LnO1.5)4(O)(C5H8O2)6(EtOH)2(CH3CN)2⋅2CH3CN (where Ln = Tb, 1; Tb/Eu, 2; and Gd, 3), featuring seven-coordinated lanthanide ions arranged in a one-capped trigonal prism geometry. Compounds 1 and 2 exhibit characteristic Tb3+ and Tb3+/Eu3+-related emissions, respectively, sensitized by the chelating antenna acetylacetonate (acac) ligands upon excitation in the UV and visible spectral regions. Compound 3 is used to assess the energies of the triplet states of the acac ligand. For compound 1, theoretical calculations on the intramolecular energy transfer and multiphonon rates indicate a thermal balance between the 5D4 Stark components, while the mixed Tb3+/Eu3+ analog 2, with a Tb:Eu ratio of 3:1, showcases intra-cluster Tb3+-to-Eu3+ energy transfer, calculated theoretically as a function of temperature. By utilizing the intensity ratio between the 5D4→7F5 (Tb3+) and 5D0→7F2 (Eu3+) transitions in the range 11–373 K, we demonstrate the realization of a ratiometric luminescent thermometer with compound 2, operating in the range 11–373 K with a maximum relative sensitivity of 2.0% K−1 at 373 K. These findings highlight the potential of cage-like silsesquioxanes as versatile materials for optical sensing-enabled applications.

To address the challenges associated with corn stover utilization and the synthesis of phenyl- and methacryloyloxy-based silsesquioxanes (SQs) with difficulty and poor controllability, the authors present a novel approach that combines advanced biorefining techniques and innovative chemical synthesis methods. Spirocyclic alkoxysilane synthesized from corn stover ash was subsequently utilized for the synthesis of phenylSQs. The resulting phenylSQs were then subjected to fluorine ion-catalyzed rearrangement with 3-(trimethoxysilyl)propyl methacrylate (KH570) to yield SQs containing phenyl and methacryloyloxy functional groups. Through manipulating the ratio of phenylSQs and KH570, the authors successfully achieved a desired ratio of functional groups on individual SQ cages. Optimization of the ratio significantly impacted product collection, with a range of 5.5:1 to 8.5:1 recommended for efficient and effective synthesis. This study represents an important advancement in the field of high-value conversion of biomass, offering an easy means of tailoring the structure of phenyl- and methacryloyloxy-based cage SQs.

[Display omitted] • Earth-Abundant 3d metal catalysis. • Excellent chemoselecitivity. • Substantial scope including dihydrosiloxanes and functionalized silsesquioxanes. • Further applications including a one-pot sequential silanolysis/alcoholysis. • Unprecedented dehydrocoupling reaction between germanol and hydrosilane. Disclosed is a mild, scalable, and chemoselective cross-dehydrogenative functionalization protocol for the construction of Si−O−Si moieties under cobalt catalysis. The reaction has a broad scope and can be used to synthesize a wide range of silicon building blocks, including challenging dihydrosiloxanes and functionalized silsesquioxanes. Most importantly, the results are placed into context by benchmarking with state-of-the-art methods. Remarkably, the utilized PNP-Co catalyst enables the development of further synthetic strategies such as a one-pot sequential silanolysis/alcoholysis process or unprecedented dehydrocoupling reaction between germanol and hydrosilane. [ABSTRACT FROM AUTHOR]

Recently, silsesquioxanes (SSQ) and polyhedral oligomeric silsesquioxanes (POSS) have gained much interest in the area of biomaterials, mainly due to their intrinsic properties such as biocompatibility, complete non-toxicity, the ability to self-assemble and to form a porous structure, facilitating cell proliferation, creating a superhydrophobic surface, osteoinductivity, and ability to bind hydroxyapatite. All the above has resulted in new developments in medicine. However, the application of POSS-containing materials in dentistry is still at initial stage and deserves a systematic description to ensure future development. Significant problems, such as reduction of polymerization shrinkage, water absorption, hydrolysis rate, poor adhesion and strength, unsatisfactory biocompatibility, and corrosion resistance of dental alloys, can be addressed by the design of multifunctional POSS-containing materials. Because of the presence of silsesquioxanes, it is possible to obtain smart materials that allow the stimulation of phosphates deposition and repairing of micro-cracks in dental fillings. Hybrid composites result in materials exhibiting shape memory, as well as antibacterial, self-cleaning, and self-healing properties. Moreover, introducing POSS into polymer matrix allows for materials for bone reconstruction, and wound healing. This review covers the recent developments in the field of POSS application in dental materials and gives the future perspectives within a promising field of biomedical material science and chemical engineering. [ABSTRACT FROM AUTHOR]

Titanium dioxide is a commonly used ingredient in cosmetics acting as a thickening agent and inorganic UV filter. However, TiO2 is difficult to disperse, which causes problems in spreading the formulations. The solution to this problem is to modify the titanium dioxide surface to change its properties by creation of the new type of hybrid inorganic–organic UV filter. Therefore, this study aimed to functionalize titanium dioxide with organosilicon compounds and determine how this modification will affect the dispersibility of TiO2 in the colloidal system and the stability of emulsions. First, the functionalized octaspherosilicates were obtained and characterized. Next, the synthesized compounds were applied as modifiers for titanium dioxide and were analyzed by FT-IR, UV-Vis, and laser diffraction. Furthermore, the hydrophilic–hydrophobic character was assessed by measuring the contact angle. The new materials were introduced into emulsions and the formulations were analyzed in terms of particle size distribution and stability by multiple light scattering. It was found that the modification of titanium dioxide with spherosilicates significantly improved both the stability of emulsion and the dispersibility of novel materials in the colloidal system compared to nonmodified TiO2. The covalent binding of the modifier with the titanium dioxide had an impact on the stability of the emulsion. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR), infrared (IR), and Raman spectroscopy are used to determine the structures and substituent groups of siloxanes and silsesquioxanes. Electronic characteristics cause NMR signals and IR bands to shift and overlap. Therefore, they are often assigned incorrectly. Unfortunately, for siloxanes and silsesquioxanes, the sheer volume of data makes it difficult to obtain the desired information. In this paper, we summarize NMR, IR, and Raman data for siloxanes and silsesquioxanes. Highlights: NMR, IR, and Raman data for siloxanes and silsesquioxanes are summarized. NMR signals and IR bands shift by linear, cyclic, ladder, and cage structures. NMR signals shift with substituent groups such as alkoxy, hydroxy, and organic groups. [ABSTRACT FROM AUTHOR]

A Polyhedral oligomeric silsesquioxane (POSS) doped with cerium (III) was synthesized and reacted with potassium hexacyanoferrate (SCeH). The vibrational, structural, morphological and electrochemical properties of this compound were studied by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopic, X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray and voltammetry using a modified graphite paste electrode. The modified paste electrode containing SCeH (SCeGPE) verified one redox pair with formal potential Eθ' = 0.33 V ± 0.01 (vs Ag/AgCl, KCl, 1.0 mol L−1; v = 100 mV s−1), attributed to the Fe2+/Fe3+ process in the presence of Cerium (III) cyanoferrate. The redox couple presents a high sensitivity and wide response range in the detection of L-dopamine. The limit of detection and amperometric sensibility were established at 4.08 × 10–4 mol L−1 and 8.27 × 10−6 mol L−1 employing the voltammetric and chronoamperometric methods respectively. [ABSTRACT FROM AUTHOR]

This article presents the synthesis of new derivatives of octa(3‐thiopropyl)silsesquioxane (SSQ‐8SH) via thiol‐ene reaction with simple olefins bearing alkyl groups as well as methoxysilyl, substituted aryl or fluoroalkyl groups. All products were characterized by 1H NMR, 13C NMR, 29Si NMR, FTIR, GPC, MALDI‐TOF‐MS, as well as thermal analysis (TGA) to confirm their structures, purity and thermal stability, and finally give some insight into their thermal degradation pathway. In some of the structures obtained, the T5% values take place at high temperatures and are close to 230 °C. The thiol‐ene reaction allowed to obtain 7 new compounds with high yield (>92 %), no by‐products and in a relatively short time (24 h). All products are characterized by high conversion >99 %. New derivatives can find potential use as modifiers of plastics to improve their certain properties for example hydrophobicity or thermo‐oxidative stability. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNC)‐based foams are promising tissue engineering materials that may facilitate implant‐tissue integration and allow localized and controlled drug delivery. Herein, hybrid CNC‐based foams, which are ultralightweight (30–100 mg cm−3), highly porous (>95%), ominiphilic and superabsorbent (1500–3000 wt% of water and/or toluene uptake) are obtained by the in situ condensation of poly(ethylene glycol) ditriethoxysilyl (TES‐PEG‐TES) into a 3D network, where silsesquioxane nanoparticles (SS‐NP) are the crosslinking nodes, and CNC are entrapped forming ionic interactions, in a supramolecular structure. In a new approach, using 3‐mercaptopropyltrimethoxysilane, sulfhydryl groups are inserted on the SS‐NP periphery and S‐nitrosated to enable the functionalization of SS‐NP with S‐nitrosothiol groups, which can nitric oxide (NO), in a process triggered by the hydration of the foams and modulated by their supramolecular structure. CNC‐SS‐PEG foams exhibit elevated thermal and structural stability, compressive strength compatible with various soft human tissues, and NO release rates (1–18 pmol mg−1 min−1) within the range of the beneficial NO actions. Thus, the CNC‐SS‐PEG foams herein described represent a new platform of supramolecular hybrid materials for localized delivery of NO, with potential uses in tissue engineering and other biomedical applications. [ABSTRACT FROM AUTHOR]

In this paper, several methods of hydrophobization of cotton fabrics using the thio-ene click reaction were compared. Durable, superhydrophobic textiles were obtained in an easy way. Various variants of functionalized silsesquioxanes were used for the hydrophobization of fabrics. The synthesis of bifunctional silsesquioxanes (RSiMe2O)4(ViSiMe2O)4Si8O12 and (RSiMe2O)4(R'SiMe2O)4Si8O12 were performed via hydrothiolation of silsesquioxane derivative (ViSiMe2O)8Si8O12. Alkoxysilyl, alkyl and fluoroalkyl moieties were introduced as functional groups. Samples were prepared using four methods, differing in the modification method and the number of stages. During the research, fabrics were modified via (a) the dip-coating process, (b) carrying out thiol-ene click reactions directly on the surface of the fabric and (c) using both of these methods. The hydrophobicity of the fabric was evaluated by measuring the Water contact angle (WCA). The obtained samples were also examined using infrared analysis (FT-IR), Scanning electron microscope (SEM), and Elemental analysis (SEM–EDS). All analyses were performed before and after the washing process in order to verify the stability of the performed modifications. [ABSTRACT FROM AUTHOR]

Recently, silsesquioxanes (SSQ) and polyhedral oligomeric silsesquioxanes (POSS) have gained much interest in the area of biomaterials, mainly due to their intrinsic properties such as biocompatibility, complete non-toxicity, the ability to self-assemble and to form a porous structure, facilitating cell proliferation, creating a superhydrophobic surface, osteoinductivity, and ability to bind hydroxyapatite. All the above has resulted in new developments in medicine. However, the application of POSS-containing materials in dentistry is still at initial stage and deserves a systematic description to ensure future development. Significant problems, such as reduction of polymerization shrinkage, water absorption, hydrolysis rate, poor adhesion and strength, unsatisfactory biocompatibility, and corrosion resistance of dental alloys, can be addressed by the design of multifunctional POSS-containing materials. Because of the presence of silsesquioxanes, it is possible to obtain smart materials that allow the stimulation of phosphates deposition and repairing of micro-cracks in dental fillings. Hybrid composites result in materials exhibiting shape memory, as well as antibacterial, self-cleaning, and self-healing properties. Moreover, introducing POSS into polymer matrix allows for materials for bone reconstruction, and wound healing. This review covers the recent developments in the field of POSS application in dental materials and gives the future perspectives within a promising field of biomedical material science and chemical engineering.

Titanium dioxide is a commonly used ingredient in cosmetics acting as a thickening agent and inorganic UV filter. However, TiO2 is difficult to disperse, which causes problems in spreading the formulations. The solution to this problem is to modify the titanium dioxide surface to change its properties by creation of the new type of hybrid inorganic–organic UV filter. Therefore, this study aimed to functionalize titanium dioxide with organosilicon compounds and determine how this modification will affect the dispersibility of TiO2 in the colloidal system and the stability of emulsions. First, the functionalized octaspherosilicates were obtained and characterized. Next, the synthesized compounds were applied as modifiers for titanium dioxide and were analyzed by FT-IR, UV-Vis, and laser diffraction. Furthermore, the hydrophilic–hydrophobic character was assessed by measuring the contact angle. The new materials were introduced into emulsions and the formulations were analyzed in terms of particle size distribution and stability by multiple light scattering. It was found that the modification of titanium dioxide with spherosilicates significantly improved both the stability of emulsion and the dispersibility of novel materials in the colloidal system compared to nonmodified TiO2. The covalent binding of the modifier with the titanium dioxide had an impact on the stability of the emulsion.

A novel silsesquioxane and cobalt nitroprusside compound was prepared from octa(aminopropyl)silsesquioxane, resulting in a nanocomposite (ACCoN), which was then characterized by different spectroscopic techniques. The cyclic voltammograms of the ACCoN‐modified graphite paste electrode indicated a redox pair with a formal potential (Eθ′)=0.38 V, assigned to the Co(II)Fe(II)(CN)5NO/Co(II)Fe(III)(CN)5NO redox couple. The ACCoN‐modified graphite paste electrode was sensitive to isoniazid concentrations, presenting a linear response at a concentration range from 6.0×10−7 to 1.0×10−5 mol L−1, with limit of detection and amperometric sensitivity of 5.53×10−7 mol L−1 and 0.17 A/mol L−1, respectively. [ABSTRACT FROM AUTHOR]

We report here the synthesis, structure, luminescence, and magnetic properties of three new cage-like tetranuclear silsesquioxanes (Et4N)2[(PhSiO1.5)8(Y0.75Dy0.25O1.5)4(O)(NO2.5)6(EtOH)2(MeCN)2] and (Cat)2[(PhSiO1.5)8(DyO1.5)4(O)(NO2.5)6(EtOH)2(MeCN)2] (Cat=Et4N or Ph4P). They present a characteristic green-yellow emission. The Y3+/Dy3+ compound displays in addition a field-induced Single Molecule Magnet (SMM) behavior making it the first reported bifunctional magneto-luminescent silsesquioxane. [ABSTRACT FROM AUTHOR]

Synthesis and study of the physicochemical properties of silsesquioxanes modified with 3-aminopropyl, 2-aminoethyl-3-aminopropyl, and dithiooxamide groups was carried out. The obtained sorbents were characterized by thermal stability, porosity, and a high degree of functionalization; the concentration of groups grafted to the particle surface reached 2.80 mmol g−1. Modified silsesquioxanes were used as an electroactive substance for the development of indicator carbon paste electrodes (CPEs). When using a CPE with a 5% dithiooxamidated silsesquioxane content, the conditions selected for potentiometric titration of aqueous solutions containing silveri were pH 3–4, the titrant was potassium iodide. The designed sensor was successfully tested by analyzing a standard sample and a drug for silver ion content. [ABSTRACT FROM AUTHOR]

This mini-review summarizes the applications of olefin metathesis in synthesis and functionalization of polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials. Three types of processes, i.e., cross metathesis (CM) of vinyl-substituted POSS with terminal olefins, acyclic diene metathesis (ADMET) copolymerization of divinyl-substituted POSS with α,ω-dienes and ring-opening metathesis polymerization (ROMP) of POSS-substituted norbornene (or other ROMP susceptible cycloolefins) are discussed. Emphasis was put on the synthetic and catalytic aspects rather than on the properties and applications of synthesized materials.

Multiple studies have explored using cage silsesquioxanes (SQs) as backbone elements in hybrid polymers motivated by their well‐defined structures and physical and mechanical properties. As part of this general exploration, we report unexpected photophysical properties of copolymers derived from divinyl double decker (DD) SQs, [vinyl(Me)Si(O0.5)2][PhSiO1.5]8[(O0.5)2Si(Me)vinyl] (vinylDDvinyl). These copolymers exhibit strong emission red‐shifts relative to model compounds, implying unconventional conjugation, despite vinyl(Me)Si(O‐)2 siloxane bridges. In an effort to identify minimum SQ structures that do/do not offer extended conjugation, we explored Heck catalyzed co‐polymerization of vinyl‐ladder(LL)‐vinyl compounds, vinyl(Me/Ph)Si(O0.5)2[PhSiO1.5]4(O0.5)2Si(Me/Ph)vinyl, with Br‐Ar‐Br. Most surprising, the resulting oligomers show 30–60 nm emission red‐shifts beyond those seen with vinylDDvinyl analogs despite lacking a true cage. Further evidence for unconventional conjugation includes apparent integer charge transfer (ICT) between LL‐co‐thiophene, bithiophene, and thienothiophene with 10 mol % F4TCNQ, suggesting potential as p‐type doped organic/inorganic semiconductors. [ABSTRACT FROM AUTHOR]

The synthesis and mechanical properties of photoswitchable silsesquioxane/azobenzene hybrid 3D‐polymers ("dynamic sponges") are presented and discussed. The hybrid is capable of extensive macroscopic movement, and overcomes previously problematic crosslink locking issues. A hydride‐functionalized Q‐type silsesquioxane (Q8M8H) is reacted with di‐allyloxyazobenzene using hydrosilylation methods. The properties of the resulting materials are controlled via careful choice of starting material ratios and solvent, leading to gels or films. Both morphologies show pronounced photoresponsive behavior in and on the surfaces of different solvents. Photoactuation is tracked by microscopy, dynamic mechanic analysis, and UV–vis spectroscopy. The gel system has a porous structure similar to a sponge. It undergoes shrinkage in volume by 18.3% in toluene under UV irradiation, and shows excellent recovery to the swollen state after irradiation with visible light. These novel photodynamic materials offer reversible modulus switching from 160 kPa in the swollen state to 500 kPa in the "wrung‐out" sponge. The sponges can engage in uptake and release of a range of substances (i.e., reversible hydrophobic sponging), with overall performance determined by solvent specific quantities such as polarity and size. Such behavior gives these materials high potential for soft robotics applications and great promise as reusable environmental remediators. [ABSTRACT FROM AUTHOR]

The synthesis of organo‐functionalized polyhedral oligomeric silsesquioxanes (POSS, (R‐SiO1.5)n, Tn) is an area of significant activity. To date, T14 is the largest such cage synthesized and isolated as a single isomer. Herein, we report an unprecedented, single‐isomer styryl‐functionalized T18 POSS. Unambiguously identified among nine possible isomers by multinuclear solution NMR (1H, 13C, and 29Si), MALDI‐MS, FTIR, and computational studies, this is the largest single‐isomer functionalized Tn compound isolated to date. A ring‐strain model was developed to correlate the 29Si resonances with the number of 6‐, 5‐, and/or 4‐Si‐atom rings that each non‐equivalent Si atom is part of. The model successfully predicts the speciation of non‐equivalent Si atoms in other families of Tn compounds, demonstrating its general applicability for assigning 29Si resonances to Si atoms in cage silsesquioxanes and providing a useful tool for predicting Si‐atom environments. [ABSTRACT FROM AUTHOR]

We report the synthesis and single-crystal X-ray diffraction, magnetic, and luminescence measurements of a novel family of luminescent cage-like tetranuclear silsesquioxanes (PhSiO 1.5 ) 8 (LnO 1.5 ) 4 (O)(C 5 H 8 O 2 ) 6 (EtOH) 2 (CH 3 CN) 2 ⋅2CH 3 CN (where Ln = Tb, 1 ; Tb/Eu, 2 ; and Gd, 3 ), featuring seven-coordinated lanthanide ions arranged in a one-capped trigonal prism geometry. Compounds 1 and 2 exhibit characteristic Tb 3+ and Tb 3+ /Eu 3+ -related emissions, respectively, sensitized by the chelating antenna acetylacetonate (acac) ligands upon excitation in the UV and visible spectral regions. Compound 3 is used to assess the energies of the triplet states of the acac ligand. For compound 1 , theoretical calculations on the intramolecular energy transfer and multiphonon rates indicate a thermal balance between the 5 D 4 Stark components, while the mixed Tb 3+ /Eu 3+ analog 2 , with a Tb:Eu ratio of 3:1, showcases intra-cluster Tb 3+ -to-Eu 3+ energy transfer, calculated theoretically as a function of temperature. By utilizing the intensity ratio between the 5 D 4 → 7 F 5 (Tb 3+ ) and 5 D 0 → 7 F 2 (Eu 3+ ) transitions in the range 11-373 K, we demonstrate the realization of a ratiometric luminescent thermometer with compound 2 , operating in the range 11-373 K with a maximum relative sensitivity of 2.0% K -1 at 373 K. These findings highlight the potential of cage-like silsesquioxanes as versatile materials for optical sensing-enabled applications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Félix, Kulakova, Sene, Khrustalev, Hernández-Rodríguez, Shubina, Pelluau, Carlos, Guari, Carneiro Neto, Bilyachenko and Larionova.)

While smaller polyhedral oligomeric silsesquioxanes T n R n (POSS) are readily accessible or even commercially available, unambiguously authenticated larger systems (n>12) have barely been reported. Synthesis and isolation procedures are lengthy, and yields are often very low. Herein, we present the surprisingly straightforward and high-yielding access to the phenyl-substituted derivative of a so far only postulated second D 3h -symmetric T 14 isomer and with that the largest crystallographically characterized POSS cage with organic substituents. Treatment of the commercially available incompletely condensed T 7 Ph 7 (OH) 3 silsesquioxane with catalytic amounts of trifluoromethanesulfonic acid results in high yields of the T 14 Ph 14 framework, which is isolated in crystalline form by a simple work-up. D 3h -T 14 Ph 14 was analyzed by single crystal X-ray diffraction, multinuclear NMR spectroscopy and thermal analysis. The relative energies of all four theoretically possible T 14 Ph 14 isomers were determined by optimization of the corresponding structure using DFT methods., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Compounds of the silsesquioxane type are attractive material precursors. High molecular weights and well-defined structures predestine them to create ceramics with a controlled composition at the molecular level. New molecular precursors of ceramic materials with the ratio of Si:Ge = 7:1 atoms were obtained. The influence of organic substituents on the thermal decomposition processes of germasilsesquioxanes was investigated. Some of the structures obtained are characterized by a high non-volatile residue after the thermal decomposition process. The introduction of the germanium atom to the structure of the silsesquioxane molecular cage reduces the thermal stability of the obtained structures.

The rising demand for innovative and sophisticated personal care products is a driving factor for manufacturers to obtain new formulations that will fulfill the customers’ preferences. In recent years, silsesquioxanes have attracted the attention of the cosmetics industry. These compounds have been proposed to be used in novel cosmetic formulations as emollient, dispersant, and viscosity modifiers. Therefore, this publication aims to review the main important aspects of polyhedral oligosilsesquioxanes as ingredients of personal care formulations, taking into consideration different types of products. The methods of obtaining these compounds were also presented. Additionally, the detailed analysis of patents dedicated to the application of silsesquioxanes in cosmetic formulations was also performed.

The recent demand for fluorescent‐labeled materials (FLMs) in forensic security concepts such as latent fingerprints (LFs) that encode information for anti‐counterfeiting and encryption of confidential data makes necessary the development of building new and innovative materials. Here, novel FLMs based on polyhedral oligomeric silsesquioxanes (POSS) functionalized with fluorophores via "click" reactions have been successfully synthesized and fully characterized. A comprehensive study of their photophysical properties has displayed large Stokes's shift together with good photostability in all cases, fulfilling the fundamental requisites for any legible LF detection on various surfaces. The excellent performance of the hetero‐bifunctional FLM in the visualization of LF is emphasized by their legibility, selectivity, sensitivity and temporal photostability. In this study, development mechanisms have been proposed and the overall concept constitute a novel approach for vis‐à‐vis forensic investigations to trace an individual's identity. [ABSTRACT FROM AUTHOR]

We report here functionalizing borasilsesquioxanes in a cross‐metathesis reaction in the presence of a ruthenium catalyst. The procedure provides new, silsesquioxanes containing boron atoms in their structure, which may find potential application in the preparation of special materials, e.g. flame retardants for polymers, organoboron Lewis acids for catalysts and scavengers, or molecular probes. The most attractive aspect of this study was obtaining hybrid silsesquioxane systems in the metathesis reaction of styrylborasilsesquioxane with mono‐ and octavinylsilsesquioxanes as well as diborate systems with vinylborate derivatives. Most of the compounds were obtained in good yields (> 75 %) and were characterized by spectroscopic methods (NMR, MALDI‐TOF‐MS). [ABSTRACT FROM AUTHOR]

In this paper we present the synthesis of mixed bifunctional compounds of T8H8 silsesquioxane and spherosilicate (HSiMe2O)8Si8O12 derivatives via platinum‐catalyzed hydrosilylation of alkenylgermanes and olefins. To the best of our knowledge, this is the first literature example of bifunctional compounds with organogermyl functionalities. Eleven mixed systems with a variety of substituents (Si−H, alkyl, germyl, epoxy, and hydroxy) were prepared and fully characterized by NMR spectroscopy. Additionally, our research includes a real‐time FT‐IR study of the synthesis of these bifunctional compounds of the general formula (R)8‐m(GeR'3(CH2)n+2R)mSi8O12. and (R"(CH2)2R)8‐m(GeR'3(CH2)2R)mSi8O12 where m∼4. [ABSTRACT FROM AUTHOR]

Tuning the geometry of Langmuir Schaefer films by using polyhedral oligomeric silsesquioxanes decorated with different metal ions. Incorporation of isolated metal centers into well-organized nanostructures is a promising route in the development of the next generation of chemical, magnetic and electronic devices. In this work, a layer-by-layer protocol to grow highly ordered thin films of metal-decorated organic-inorganic cage-like polyhedral oligomeric silsesquioxane (POSS) is introduced. The key strategy is to use metal ions (Cu2+ or Fe3+) as linker for the amino-functionalized cage-like POSS, which are self-assembled between arachidic acid layers during Langmuir–Schaefer deposition. The Langmuir–Schaefer films are examined by X-ray photoelectron spectroscopy, X-ray diffraction, grazing incidence wide-angle X-ray scattering and extended X-ray absorption fine structure in order to understand how the coordination of metal ions influences the structure in the course of the layer-by-layer formation of the films. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Hybrid nanostructures with switchable and reversible "blue‐red‐green" emission were efficiently synthesized. These nanostructures comprise polyhedral oligomeric silsesquioxanes (POSS) that behave as a nanocage that can be functionalized with terpyridine‐based organic ligands, which can be easily complexed with europium (III) ions. The complexes were characterized by UV‐Vis and fluorescence spectroscopy and their stoichiometry was also confirmed by 1H NMR spectroscopy. In the presence of the Eu(III) ions, the octafunctionalized nanocages self‐assemble to form 3D architectures that display an intense red‐emission, especially in the solid state. The presence of an alkenyl group bridging the inorganic core to the organic moiety was employed to tune the emission properties by trans‐cis isomerization of the double bond. In the case of the octafunctionalized nanocages (O‐POSS), this isomerization was monitored in the presence of Eu(III) cations and was accompanied by an evident colour change from blue (trans‐O‐POSS) to red (Eu@trans‐O‐POSS) and finally to green (cis‐O‐POSS) as consequence of the release of the metal cations. This behaviour, together with the easy dispersion of the dry powder and the possibility of coating as a film in presence of small amounts of solvent, makes the emissive solid promising for applications in materials science. [ABSTRACT FROM AUTHOR]

The nano-sized SQS based polyimides have been successfully synthesized with different oxide groups such as phosphineoxide, sulfone and siloxane as in the backbone of polymer. The SQS-Polyimide nanocomposites prepared through the condensation process using amine and epoxy functionalized SQS as precursor. The presence of SQS in the resulting polyimide nanocomposites was confirmed by FTIR and XRD analyses. The presence of SQS and greatly enhances the char yield to an extent of 16% when compared to that of neat polyimide. The incorporation of SQS into polyimide lowered the value of dielectric constant from 3.31 to 2.09 at 1 MHz and the value of thermal expansion coefficient from 56.6 to 42.7 ppm/K. The composites sample prepared using 20 wt% SQS possess the lowest value of dielectric constant and CTE value. The hydrophobic nature of SQS contributes to lower the water uptake of composites from a value of 2.76 (neat polyimide) to 2.42 for POS-PI containing 20 wt% SQS. Further, the SQS polyimide composite systems possess the enhanced values of thermal stability and glass transition temperatures according their percentage weight. Data obtained from different studies, it is suggested that these hybrid composites can be used as an effective insulation materials for high performance microelectronics applications. [ABSTRACT FROM AUTHOR]

Octa-(3-chloropropyl) octasilsesquioxane (SS) was functionalized with a PAMAM dendrimer (SP) and characterized by some spectroscopic techniques such as Fourier Transform Infrared, Nuclear Magnetic Resonance, X-ray diffraction, X-ray Dispersive Energy Spectroscopy, Scanning Electron Microscopy and cyclic voltammetry. As a fast application, after there the Ag+ was adsorbed by SP and in a second step, the resulting material was reacted with potassium hexacyanoferrate (III) (AgHSP). The cyclic voltammogram of the AgHSP showed two redox pairs with formal potentials (Eθ') of Eθ'(I) = 0.26 V and Eθ'(II) = 0.71 V (v = 20 mV s−1, KNO3 1.00 mol L−1, pH 7.00) assigned to processes Ag0 / AgI and FeII (CN)6 / FeIII (CN)6, respectively. The analytical application of this new material (AgHSP) was tested in the rapid detection of acid ascorbic by strong electrocatalysis using graphite paste electrode (GPE). The limit of detection (LOD) obtained for this system was 7.034 × 10−5 mol L−1 with an excellent amperometric sensitivity of 0.0835 A / mol L−1. [ABSTRACT FROM AUTHOR]

Octakis(2-carboxyethyl-thioethyl)silsesquioxane (T 8 -COOH), a structurally well-defined organo-functionalized nano-silica, was used as an addition in different percentages (up to 15 wt.%) to a high molecular mass PDMS, obtaining composites that were processed as films by solution casting and stabilized by condensation crosslinking. SEM images showed a common aggregation phenomenon within polymeric matrix at high filler concentration. The presence of T 8 -COOH pushed the main stage of thermal decomposition to higher temperatures, generally around 500 °C, as compared to 400 °C for pure PDMS. The mechanical strength of the obtained composites was also enhanced by increased addition of filler that acts as a reinforcing agent. Tensile toughness, strains at break, and Young's modulus increased with increasing filler content. The viscoelastic behavior of the silicone composites was evaluated in five cyclic stress-strain tests. All materials showed relatively large hysteresis loops for the first cycle due to Mullin's effect, while the subsequent hysteresis became smaller from the second cycle. The composites showed dielectric behavior with low loss (<10−1), relative permittivity superior to pure siloxane (4–5 vs. 3.4), and slightly increased electrical breakdown strength (30–36 V/μm vs. 27 V/μm). The applicative potential of these composites in electromechanical devices was estimated by calculated figures of merit, based on mechanical and dielectric parameters, which indicate their suitability for energy harvesting/capacitive sensors rather than for actuators. In addition, the composite with the highest ε′ was tested as capacitive pressure sensor, showing a high sensitivity at low pressure, with potential application in wearable devices. [Display omitted] • A PDMS-α,ω-diol is engineered for application in dielectric elastomer transducers. • Octacarboxy-functionalized POSS is used as active filler for silicone. • Mechanical, thermal properties, dielectric permittivity and strength are improved. • High sensitivity at low pressure indicates potential application in wearable devices. • Calculations indicate the composite more suitable for dielectric elastomer generator. [ABSTRACT FROM AUTHOR]

The bicyclic silicon(I) ring compound Si 4 {N(SiMe 3 )Mes} 4 (2) was used as starting material in reactions with chalcogens and chalcogen transfer agents at low temperatures. This resulted in the selective formation of new cage compounds. With Me 3 NO, a silicon oxide with adamantane-type cage 3 was isolated that represents the first isolated T 4 silsesquioxane. Reactions with propylenesulfide and red selenium gave direct access to defect heterocubane-type cages 4 and 5 with three Si-Si bonds wherein the silicon atoms adopt different low oxidation states of +I and +III. A reaction with elemental tellurium even occurs below room temperature to provide ditelluro-tetrasila-tricyclohexane 6., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The aim of this work was to synthesize porous ceramic materials from the SiOC system by the sol-gel method and the subsequent pyrolysis. The usage of two types of precursors (siloxanes) was determined by Si/C ratio in starting materials. It allows us to control the size of the pores and specific surface area, which are crucial for the potential applications of the final product after thermal processing. Methyltrimethoxysilane and dimethyldiethoxysilane were mixed in three different molar ratios: 4:1, 2:1, and 1:1 to emphasize Si/C ratio impact on silicon oxycarbide glasses properties. Structure and microstructure were examined both for xerogels and obtained silicon oxycarbide materials. Brunauer-Emmett-Teller (BET) analysis was performed to confirm that obtained materials are porous and Si/C ratio in siloxanes precursors affects porosity and specific surface area. This kind of porous ceramics could be potentially applied as gas sensors in high temperatures, catalyst supports, filters, adsorbents, or advanced drug delivery systems.