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A mild and highly selective hydrosilylation method was employed to synthesize five novel well-defined Janus ring siloxanes bearing terpenes and terpenoids, which are the main bioactive components of essential oils. The characterization of these new bio-sourced molecular materials, derived from hydrosilyl-substituted all-cis-cyclotetrasiloxane, was conducted through comprehensive analyses using multinuclear NMR, infrared spectroscopy, elemental analysis, and mass spectroscopy. The thermal stability of the newly synthesized Janus rings was investigated, and the siloxane skeleton was shown to confer an enhanced thermal stability compared with free terpenes and terpenoids. [ABSTRACT FROM AUTHOR]

In the context of growing interest in phosphonic acid proton exchange membranes (PEMs) for fuel cell applications, we report on new PEMs containing low‐cost polyethylene oxide (PEO) covalently linked by siloxane bonds, SiOSi, to phosphonic acid (PA). Key chemistry in the formation of these membranes involves hydrolysis and condensation reactions of triethoxysilyl propyl capped PEO and pre‐hydrolyzed dimethyl phosphonatoethyltrimethoxysilane (DMPTMS) giving PEO‐Si2O3‐PA and cross‐linked chain PEO‐Si2O3‐PEO organosilsesquioxane components. The Si2O3 can enhance membrane thermal and mechanical properties. The membrane formulations were varied by (a) reagent ratios (b) PEO molecular weights or using polypropylene oxide (PPO) (c) incorporating chain extending groups methylene diphenyl diisocyanate (MDI) or hexamethylene diisocyanate (HDI). These variations provided five membrane families, one of which afforded a complete group of robust membranes with weight% x of PA, PAx in range PA0–PA33. These were studied using ATR‐FTIR, dry membrane water uptake capacity, ion exchange capacity (IEC), and conductivity from room temperature to 120°C at 100% relative humidity. Conductivity increased with PAx reaching 15 mS cm−1 at 120°C, activation energy 0.1 eV, for membrane PA33 for which thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and energy dispersive X‐ray analysis (EDAX) are reported. A comparative performance of the five membrane families is presented. [ABSTRACT FROM AUTHOR]

Abstract We present a methodology for the synthesis of inorganic-organic Janus-type molecules based on mono-T8 and difunctionalized double-decker silsesquioxanes (DDSQs) via hydrosilylation reactions, achieving exceptionally high yields and selectivities. The synthesized compounds were extensively characterized using various spectroscopic techniques, and their sizes and spatial arrangements were predicted through molecular modelling and density functional theory (DFT) calculations. Quantum chemical calculations were employed to examine the interactions among four molecules of the synthesized compounds. These computational results allowed us to determine the propensity for molecular aggregation, identify the functional groups involved in these interactions, and understand the changes in interatomic distances during aggregation. Understanding the aggregation behaviour of silsesquioxane molecules is crucial for tailoring their properties for specific applications, such as nanocomposites, surface coatings, drug delivery systems, and catalysts. Through a combination of experimental and computational approaches, this study provides valuable insights into the design and optimization of silsesquioxane-based Janus-type molecules for enhanced performance across various fields.

A new metallohybrid silsesquioxane (S) was synthesized herein from copper and ferricyanide via a cyanide bridge to produce a new electroactive hybrid material (SCuH), which was then characterized by spectroscopic and microscopic techniques and cyclic voltammetry. The voltammetric behavior of SCuH employing a graphite paste electrode indicates a well‐defined redox couple with formal potential Eθ′=0.76±0.01 V. The electrode exhibited high sensitivity to nitrite and was successfully tested for nitrite detection. The linearity of the analytical curve was 2.0×10−4 mol L−1 − 1.0×10−3 mol L−1, with a limit of detection of 2.65×10−5 mol L−1, and sensitivity amperometric value of 57.63 mA/mol L−1. These findings suggest that this material displays exceptional potential for application in electrochemical sensors designed for nitrite detection. [ABSTRACT FROM AUTHOR]

We present a methodology for the synthesis of inorganic-organic Janus-type molecules based on mono-T8 and difunctionalized double-decker silsesquioxanes (DDSQs) via hydrosilylation reactions, achieving exceptionally high yields and selectivities. The synthesized compounds were extensively characterized using various spectroscopic techniques, and their sizes and spatial arrangements were predicted through molecular modelling and density functional theory (DFT) calculations. Quantum chemical calculations were employed to examine the interactions among four molecules of the synthesized compounds. These computational results allowed us to determine the propensity for molecular aggregation, identify the functional groups involved in these interactions, and understand the changes in interatomic distances during aggregation. Understanding the aggregation behaviour of silsesquioxane molecules is crucial for tailoring their properties for specific applications, such as nanocomposites, surface coatings, drug delivery systems, and catalysts. Through a combination of experimental and computational approaches, this study provides valuable insights into the design and optimization of silsesquioxane-based Janus-type molecules for enhanced performance across various fields. [ABSTRACT FROM AUTHOR]

Polymers incorporating double‐decker‐shaped phenyl‐substituted silsesquioxane (DDSQ) into the main chain are expected to exhibit excellent thermal stability and significantly reduced dynamics of the polymer segments. In this study, thiol‐ene polymerization at 25 °C for 5 min under 365 nm irradiation was applied for 3,13‐divinyl‐DDSQ (E1) with oxybis(2,1‐ethanediyloxy‐2,1‐ethanediyl) bis(3‐sulfanylpropanoate) (T1) as a bithiol monomer for linear and 2,2‐bis{[(3‐sulfanylpropanoyl)oxy]methyl}butyl 3‐sulfanylpropanoate (T2) as a trithiol monomer for soluble cross‐linked poly(thioether)s. All the resulting poly(thioether)s yielded colorless and transparent films by casting tetrahydrofuran solutions onto glass substrates. These polymers showed a higher decomposition temperature of 5 wt% loss over 350 °C. The films exhibited glass transition temperatures below 25 °C. Scratch scars were made on the surface of the cast films, and the self‐healing behavior was observed after heating at 40 °C. These results suggest that the DDSQ unit suppresses the molecular motion of the polymers and contributes to their self‐healing behavior. [ABSTRACT FROM AUTHOR]

Polyurethane (PUR), as an engineering polymer, is widely used in many sectors of industries. However, the high fire risks associated with PUR, including the smoke density, a high heat release rate, and the toxicity of combustion products limit its applications in many fields. This paper presents the influence of silsesquioxane fillers, alone and in a synergistic system with halogen-free flame-retardant compounds, on reducing the fire hazard of polyurethane foams. The flammability of PUR composites was determined with the use of a pyrolysis combustion flow calorimeter (PCFC) and a cone calorimeter. The flammability results were supplemented with smoke emission values obtained with the use of a smoke density chamber (SDC) and toxicometric indexes. Toxicometric indexes were determined with the use of an innovative method consisting of a thermo-balance connected to a gas analyzer with the use of a heated transfer line. The obtained test results clearly indicate that the used silsesquioxane compounds, especially in combination with organic phosphorus compounds, reduced the fire risk, as expressed by parameters such as the maximum heat release rate (HRRmax), the total heat release rate (THR), and the maximum smoke density (SDmax). The flame-retardant non-halogen system also reduced the amounts of toxic gases emitted during the decomposition of PUR, especially NOx, HCN, NH3, CO and CO2. According to the literature review, complex studies on the fire hazard of a system of POSS–phosphorus compounds in the PUR matrix have not been published yet. This article presents the complex results of studies, indicating that the POSS–phosphorous compound system can be treated as an alternative to toxic halogen flame-retardant compounds in order to decrease the fire hazard of PUR foam. [ABSTRACT FROM AUTHOR]

A mild and highly selective hydrosilylation method was employed to synthesize five novel well-defined Janus ring siloxanes bearing terpenes and terpenoids, which are the main bioactive components of essential oils. The characterization of these new bio-sourced molecular materials, derived from hydrosilyl-substituted all-cis-cyclotetrasiloxane, was conducted through comprehensive analyses using multinuclear NMR, infrared spectroscopy, elemental analysis, and mass spectroscopy. The thermal stability of the newly synthesized Janus rings was investigated, and the siloxane skeleton was shown to confer an enhanced thermal stability compared with free terpenes and terpenoids.

This paper reports the synthesis and characterization of an organic silsesquioxane (SQ) containing Sivinyl and SiH groups named as vinylhydridosilsesquioxane (SQVH‐12). Detailed investigation of the structure of this organosilsesquioxane revealed that SQVH‐12 has a highly cross‐linked (polycyclic) SiO network of silsesquioxane with Sivinyl and SiH functional groups. Thermogravimetric analysis of the pyrolysis behavior of SQVH‐12 yielded a high percentage of ceramic residue (~92%) at 1200°C under an argon atmosphere. The presence of functional groups in SQVH‐12 and the high rate of ceramic residue highlights the potential usefulness of SQVH‐12 as a filler for vinyl‐containing polysiloxanes. Thus, further research of SQVH‐12 can find applications in a wide variety of areas such as additive manufacturing, protective coatings, and advanced composites. [ABSTRACT FROM AUTHOR]

In this work, new partially substituted derivatives of octa(3-thiopropyl)silsesquioxane (SSQ-8SH) were synthesized. The article compares the thiol-ene reaction using two methods: radical mechanism, thermally initiated (AIBN), and in the presence of a photoinitiator (DMPA). Both the crystalline and the oil forms of SSQ-8SH were functionalized. Olefins with nonpolar alkyl groups (hexene, octene, and octadecene) and vinyltrimethoxysilane, allyl glycidyl ether, allyl 2,2,3,3,4,4,5,5-octafluoropentylether, allyl methacrylate, and styrene were used in the reactions, allowing to obtain seven new derivatives. All compounds were characterized using spectroscopic (1H NMR and 29Si NMR) and spectrometric (MALDI-TOF-MS) methods. The influence of functional groups on the water contact angle value was determined. The functionalization of the compound led to a contact angle value above 95° (SSQ-4SH-4OD). Density measurements and thermogravimetric analysis (TGA) were carried out for all compounds. The highest onset temperature (357.4 °C) and temperature at the maximum mass loss rate (377.3 °C) were observed for SSQ-SH-4OD. The addition of alkyl groups significantly decreased the density of compounds with increasing chain length (1.198 g/cm3; 1.162 g/cm3; 1.095 g/cm3 for hexene, octene, and octadecene, respectively). Silsesquioxanes have potential applications in various materials, such as UV-curable resins, allowing to modify, for example, their surface properties. Modification of a commercial photocurable resin with selected derivatives was carried out to determine the impact on physicochemical properties (TGA, WCA). [ABSTRACT FROM AUTHOR]

The direct incorporation of Sb(V) ions into a polycondensed silsesquioxane network based on heptaisobutyl POSS units (Sb(V)-POSSs) through a corner-capping reaction is reported for the first time in this work. As a reference sample, a completely condensed monomeric Sb(III)-POSS was prepared using a similar synthetic protocol. The chemical properties of both Sb-containing POSSs were investigated with different analytical and spectroscopic techniques. The analyses confirm the success of the corner-capping reaction for both samples and indicate that an Sb(V)-POSS sample is characterized by a heterogenous multimeric arrangement with an irregular organization of POSS cages linked to Sb(V) centers, and has a more complex structure with respect to the well-defined monomeric Sb(III)-POSS. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxanes (POSS) and hybrid organo-halide perovskites are two important types of hybrid nanoscale frameworks with great potential in materials chemistry. Both are currently under intensive investigation for a wide range of possible applications. Recent results suggest that POSS can be attractive passivating and structure-controlling agents for perovskite materials. In this review, we present the importance of POSS in engineering the structures of inorganic cesium-halide perovskites CsPbX3 (X = Cl, Br, I) to create a new class of hybrid derivatives with improved properties. The combination of these two components can be an effective strategy for controlling the perovskite crystallization process. In addition, passivation of surface defects/bulk and the engineering of energy and optoelectronic properties of perovskite-based materials can be achieved following this method. In this minireview, we summarized the existing literature reports on the structural specificity and properties of hybrid POSS perovskites. [ABSTRACT FROM AUTHOR]

A kind of the epoxy and phenyl groups‐containing POSS of the regular cage of 16 silicon atoms (EPHPOSS) was synthesized successfully via the hydrolysis‐condensation reaction of phenyltrimethoxysilane and 2‐(3,4‐glycidoxypropyl) propyltrimethoxysilane, and its chemical structure was characterized. To improve the comprehensive performances of the epoxy resin (EP), EPHPOSS in different ratios was incorporated into the EP by thermal curing technology. It is obtained that the EPHPOSS has a homogeneous dispersion in the EP composites and plays an important role in enhancing the bending strength and thermal properties of the EP composites. The EP composite with 10 wt% EPHPOSS has a limiting oxygen index (LOI) value of 27.8%, higher than the LOI of 23.2% of the pure EP. The peak of heat release rate, total heat release, and total smoke release of the EP composites with the EPHPOSS are reduced obviously. In flame retardant mechanism of the EPHPOSS on the EP, the microstructures of the burning char and TG‐FTIR of the EP composites were achieved, it is suggested that the EPHPOSS promotes the formation of compact and continuous char layers and reduces the production of the organic combustible gases. [ABSTRACT FROM AUTHOR]

This paper describes the author's recent work on the preparation and properties of thermally stable ionic liquids (ILs) containing siloxane frameworks. Quaternary ammonium and imidazolium salt‐type ILs containing random oligosilsesquioxane frameworks were successfully prepared via the hydrolytic condensation of the corresponding organotrialkoxysilanes by using an aqueous superacid bis(trifluoromethanesulfonyl)imide (HNTf2) solution as a catalyst and solvent. Imidazolium salt‐type ILs containing polyhedral oligomeric silsesquioxane (POSS) frameworks were also prepared through a reaction similar to that described above by using a water/methanol mixed solution of HNTf2. In addition, amorphous POSSs with two types of ionic groups randomly distributed in the side chain were prepared. These POSSs were ILs exhibiting fluidity at relatively low temperatures. Furthermore, imidazolium and ammonium salt‐type ILs containing cyclic oligosiloxane frameworks were prepared through a reaction similar to that of the corresponding organodialkoxysilanes. The thermal decomposition temperatures of the above ILs containing siloxane frameworks were higher than those of general ILs. [ABSTRACT FROM AUTHOR]

A novel dual functional and visual rhodamine ethylenediamine bis(triazolyl silsesquioxane) (RBS) chemosensor was successfully synthesized using "click" chemistry. The results have unambiguously demonstrated that RBS can act in fluorescent and colorimetric sensing of Cu2+ and Zn2+ by their respective coordination with triazole structures and, more importantly, it has also been found that triazole-amide of RBS could turn on chelation-enhanced fluorescence (CHEF) of Cu2+. Remarkably, the addition of Cu2+ triggered an enhanced fluorescent emission by 63.3-fold (ϕF = 0.41), while Zn2+ enhanced it 48.3-fold (ϕF = 0.29) relative to the original RBS (ϕF = 0.006) in acetonitrile (MeCN) solvent. The fluorescent limit of detection for Cu2+ and Zn2+ is similar and fall within 3.0 nM, while under colorimetric sensing the responses were 2.14 × 10–8 and 4.0 × 10–8 mol L−1, respectively. Moreover, the effective sensing profile of RBS and extended applications of RBS–Cu2+ and RBS–Zn2+ for fingerprinting detection and imaging were observed with adequate sensitivity, stability and legibility under the dual visual responses. [ABSTRACT FROM AUTHOR]

The study aimed to determine the influence of shear stress during real-life industrial processes such as compression molding and injection molding to different cavities on the crystallization of the isotactic polypropylene nucleated with a novel silsesquioxane-based β-nucleating agent. Octakis(N2,N6-dicyclohexyl-4-(3-(dimethylsiloxy)propyl)naphthalene-2,6-dicarboxamido)octasilsesquioxane (SF-B01) is a highly effective nucleating agent (NA) based on the hybrid organic-inorganic silsesquioxane cage. The samples containing various amounts of the silsesquioxane-based and commercial iPP β-nucleants (0.01–0.5 wt%) were prepared by compression molding and injection molding, including forming in the cavities with different thicknesses. The study of the thermal properties, morphology, and mechanical properties of iPP samples allows for obtaining comprehensive information about the efficiency of silsesquioxane-based NA in shearing conditions during the forming. As a reference sample, iPP nucleated by commercial β-NA (namely N2,N6-dicyclohexylnaphthalene-2,6-dicarboxamide, NU-100) was used. The static tensile test assessed the mechanical properties of pure and nucleated iPP samples formed in different shearing conditions. Variations of the β-nucleation efficiency of the silsesquioxane-based and commercial nucleating agents caused by shear forces accompanying the crystallization process during forming were evaluated by differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). The investigations of changes in the mechanism of interactions between silsesquioxane and commercial nucleating agents were supplemented by rheological analysis of crystallization. It was found that despite the differences in the chemical structure and solubility of the two nucleating agents, they influence the formation of the hexagonal iPP phase in a similar way, taking into consideration the shearing and cooling conditions. [ABSTRACT FROM AUTHOR]

The present study proposes a novel application of humic substance–aminosilsesquioxane polyelectrolyte complexes (HS–ASQ) as dust suppressants. These complexes are synthesized through the reaction between humic substances (HS) and 3-aminopropyltriethoxysilane (APTES) in aqueous solution, resulting in the formation of active silanol groups that can bind to mineral surfaces and condense, forming gels. The HS–ASQ compositions were found to have a high sorption capacity for dust particles and could form coatings on their surface without cementing the dust, making them potentially useful for environmental applications. The viscosity of the HS–ASQ compositions can be controlled by adding carboxymethylcellulose (CMC), which also enhances their dust suppression abilities. Different compositions of HS–ASQ were synthesized by varying the proportions of APTES and CMC, and dust treated with these samples was assessed for its resistance to wind erosion using a laboratory-scale setup. Treatment with the HS–ASQ composition resulted in substantial reductions in PM10 and PM2.5 concentrations (particulate matter with aerodynamic diameters of 10 µm and 2.5 µm, respectively) of up to 77% and 85%, respectively, compared to the control. [ABSTRACT FROM AUTHOR]

Polyurethane (PUR), as an engineering polymer, is widely used in many sectors of industries. However, the high fire risks associated with PUR, including the smoke density, a high heat release rate, and the toxicity of combustion products limit its applications in many fields. This paper presents the influence of silsesquioxane fillers, alone and in a synergistic system with halogen-free flame-retardant compounds, on reducing the fire hazard of polyurethane foams. The flammability of PUR composites was determined with the use of a pyrolysis combustion flow calorimeter (PCFC) and a cone calorimeter. The flammability results were supplemented with smoke emission values obtained with the use of a smoke density chamber (SDC) and toxicometric indexes. Toxicometric indexes were determined with the use of an innovative method consisting of a thermo-balance connected to a gas analyzer with the use of a heated transfer line. The obtained test results clearly indicate that the used silsesquioxane compounds, especially in combination with organic phosphorus compounds, reduced the fire risk, as expressed by parameters such as the maximum heat release rate (HRRmax), the total heat release rate (THR), and the maximum smoke density (SDmax). The flame-retardant non-halogen system also reduced the amounts of toxic gases emitted during the decomposition of PUR, especially NOx, HCN, NH3, CO and CO2. According to the literature review, complex studies on the fire hazard of a system of POSS–phosphorus compounds in the PUR matrix have not been published yet. This article presents the complex results of studies, indicating that the POSS–phosphorous compound system can be treated as an alternative to toxic halogen flame-retardant compounds in order to decrease the fire hazard of PUR foam.

A zinc-modified octa(aminopropyl)silsesquioxane and the cyan compound Na2[Fe(CN)5NO] were prepared to create a hybrid electroactive material (ACZnN) characterized employing the spectroscopic techniques Raman spectroscopy, Diffuse Reflectance (DR), X-Ray diffraction (XRD), Scanning Electronic Microscopy (SEM), thermogravimetric analysis (TGA) and voltammetric measurements. The cyclic voltammetry technique indicated the solid ACZnN on the electrode surface as presenting two redox processes, with EIθ' = 0.21 V and EIIθ' = 0.51 V (vs Ag/AgCl(sat)) attributed to the redox pair Fe2+(CN)5NO/ Fe3+(CN)5NO in the absence and presence of Zn2+, respectively, as well as adequate stability, reliability and efficiency for practical applications. The ACZnN-modified graphite paste electrode exhibited a sensitive and catalytic oxidation response towards N-acetylcysteine and was successfully employed 1in the catalytic electro-oxidation of N-acetylcysteine employing differential pulse voltammetry techniques. The lowest limit of detection and best amperometric sensitivity obtained by differential pulse voltammetry were 0.657 µmol L−1 and 500 mA/mol L−1, respectively, from 1.0 × 10–6 to 1.0 × 10–5 M. Further analyses applying this method also demonstrated the compound's efficiency in detecting N-acetylcysteine in synthetic urine samples. [ABSTRACT FROM AUTHOR]

The presented work is a continuation of research on the reactivity of unsaturated borasilsesquioxanes under the conditions of common organometallic transformations. The catalytic hydrosilylation reaction with silanes, siloxanes and silsesquioxanes in presence of platinum catalyst was explored. The majority of the products were obtained in high yields (>90 %) and their structures were confirmed and characterized by spectroscopy and spectrometry, i. e. NMR and MALDI‐TOF‐MS. The most significant segment of the work is research on the spontaneous redistribution reaction of the alkoxy group from silane to borane moiety occurring in the obtained products, not being limited to the heterosilsesquioxane chemistry, however. The products were confirmed using GC‐MS, ESI‐MS methods and B3LYP exchange‐correlation, in order to ascertain formation of the silicon‐boron hybrid molecule. [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 direct incorporation of Sb(V) ions into a polycondensed silsesquioxane network based on heptaisobutyl POSS units (Sb(V)-POSSs) through a corner-capping reaction is reported for the first time in this work. As a reference sample, a completely condensed monomeric Sb(III)-POSS was prepared using a similar synthetic protocol. The chemical properties of both Sb-containing POSSs were investigated with different analytical and spectroscopic techniques. The analyses confirm the success of the corner-capping reaction for both samples and indicate that an Sb(V)-POSS sample is characterized by a heterogenous multimeric arrangement with an irregular organization of POSS cages linked to Sb(V) centers, and has a more complex structure with respect to the well-defined monomeric Sb(III)-POSS.

Polyhedral oligomeric silsesquioxanes (POSS) and hybrid organo-halide perovskites are two important types of hybrid nanoscale frameworks with great potential in materials chemistry. Both are currently under intensive investigation for a wide range of possible applications. Recent results suggest that POSS can be attractive passivating and structure-controlling agents for perovskite materials. In this review, we present the importance of POSS in engineering the structures of inorganic cesium-halide perovskites CsPbX3 (X = Cl, Br, I) to create a new class of hybrid derivatives with improved properties. The combination of these two components can be an effective strategy for controlling the perovskite crystallization process. In addition, passivation of surface defects/bulk and the engineering of energy and optoelectronic properties of perovskite-based materials can be achieved following this method. In this minireview, we summarized the existing literature reports on the structural specificity and properties of hybrid POSS perovskites.

The synthesis and characterization of novel luminescent amorphous POSS-based polysilsesquioxanes (PSQs) with Tb3+ and Eu3+ ions directly integrated in the polysilsesquioxane matrix is presented. Two different Tb3+/Eu3+ molar ratios were applied, with the aim of disclosing the relationships between the nature and loading of the ions and the luminescence properties. Particular attention was given to the investigation of site geometry and hydration state of the metal centers in the inorganic framework, and of the effect of the Tb3+ → Eu3+ energy transfer on the overall optical properties of the co-doped materials. The obtained materials were characterized by high photostability and colors of the emitted light ranging from orange to deep red, as a function of both the Tb3+/Eu3+ molar ratio and the chosen excitation wavelength. A good energy transfer was observed, with higher efficiency displayed when donor/sensitizer concentration was lower than the acceptor/activator concentration. The easiness of preparation and the possibility to finely tune the photoluminescence properties make these materials valid candidates for several applications, including bioimaging, sensors, ratiometric luminescence-based thermometers, and optical components in inorganic or hybrid light-emitting devices. [ABSTRACT FROM AUTHOR]

A new potential model system for silicon monoxide (SiO) is synthesized by the interlinkage of an unsaturated silicon cluster (siliconoid) with a polyhedral silsequioxane cage. Two derivatives with variable linker size are obtained by the corner‐capping reaction of Ph7T7(ONa)3 with a trichlorosilane featuring a remote benzylic chloride functionality and the subsequent nucleophilic substitution of the latter by the anionic hexasilabenzpolarene‐type Si6 siliconoid. Based on the recently proposed heterogeneous cluster model for the SiO structure, the stoichiometry between silicon and oxygen reiterates the suboxidic interface of the nano‐composite in a Si : O ratio of 14 : 12. [ABSTRACT FROM AUTHOR]

Two octakis(carboxyalkyl-thioalkyl)silsesquioxanes (COOH-PSx) were obtained by click photo-induced thiol-ene addition reactions between octavinyl-T8-silsesquioxane and thioalkylcarboxylic acids. Their structures were confirmed by elemental and spectral analyses and in one case by single-crystal X-ray diffraction. The natrium salts of COOH-PSx were used as very efficient ligands for Cu, Ni and Cd ions. The formation of transition metals complexes was confirmed by FT-IR spectroscopy, showing the coordination pattern, and by EDX semiquantitative elemental analysis. They were analyzed in terms of thermal stability, morphology and moisture sorption. The catalytic activity was tested in alkaline decomposition of hydrogen peroxide, the copper complexes showing the best activity, that is 40% conversion after ~ 40 min. A copper complex was also efficient as catalyst in photodecomposition of Congo Red under UV light, without additional oxidation agents or pH adjustments, showing discoloration efficiency of ca. 89% after 145 min and recycling ability. Thus, the results indicated the compounds reported here, obtained by simple and reproducible synthetic protocols, as efficient, stable and re-usable heterogeneous catalyst. The possibilities of structural diversification (by the nature of the functional groups and the metal ion) are wide and of the application potential. [ABSTRACT FROM AUTHOR]

In this study, a series of cage siloxanes (CS), e.g., three polyhedral oligomeric silsesquioxanes (SSQs) and one spherosilicate (SS) derivative, were applied as functional additives for the preparation of poly(lactic acid)-based (PLA) nanofibrillar membranes with an electrospinning technique utilizing an efficient spinning wire electrode setup. The impact of the additives' structure, chemistry, and electrospinning parameters on the obtained materials' morphology (scanning electron microscopy) and physicochemical (thermogravimetry, differential scanning calorimetry, contact angle analysis, air flow analysis) properties is discussed. It is presented that applying organosilicon additives may extend the already tuneable properties of the membranes produced by electrospinning performed under different conditions and that they enable to obtain nanofibres of smaller diameter, which in turn increases the membrane porosity. Furthermore, the solvent-assisted electrospinning method allowed for unparalleled mixing of the PLA matrix with the CS additives, as no traces of free additives were visible on the membranes by scanning electron microscopy (SEM) imaging. The resulting membranes can be utilized as filter materials. [ABSTRACT FROM AUTHOR]

Highly crosslinked monolithic capillary columns with inner diameters in the range of 50–530 μm were prepared by radical polymerization of pentaerythritol tetraacrylate, polyhedral oligomeric silsesquioxane‐methacrylate, and n‐octadecyl methacrylate in the presence of methanol, dodecyl alcohol, and polyethylene glycol lauryl ether. Columns were evaluated by inverse size‐exclusion chromatography employing a set of polystyrene standards of narrow molecular‐size distribution and by scanning electron microscopy. Chromatographic performance under reversed‐phase conditions was also evaluated. The combination of two effective crosslinkers as pentaerythritol tetraacrylate and polyhedral oligomeric silsesquioxane‐methacrylate in the polymerization mixture allows for the preparation of robust and efficient monolithic capillary columns within a fairly wide range of internal diameters. [ABSTRACT FROM AUTHOR]

Nanofluidic ionic diodes have attracted much attention due to their unique functions as unidirectional ion transportation ability and promising applications from molecular sensing, and energy harvesting to emerging neuromorphic devices. However, it remains a challenge to fabricate diode-like nanofluidic systems with ultrathin film thickness <100 nm. Herein the formation of ultrathin ionic diodes from hybrid nanoassemblies of nanoporous (NP) SiO 2 nanofilms and polyelectrolyte layer-by-layer (LbL) multilayers is described. Ultrathin ionic diodes are prepared by integrating polyelectrolyte multilayers onto photo-oxidized NP SiO 2 nanofilms obtained from silsesquioxane-containing block copolymer thin films as a template. The obtained ultrathin ionic diodes exhibit ion current rectification (ICR) properties with high ICR factor = ≈20 under low ionic strength and asymmetric pH conditions. It is concluded that this ICR behavior arises from effective ion accumulation and depletion at the interface of NP SiO 2 nanofilms and LbL multilayers attributed to high ion selectivity by combining the experimental data and theoretical calculations using finite element methods. These results demonstrate that the hybrid nano assemblies of NP SiO 2 nanofilms and polyelectrolyte LbL multilayers have potential applications for (bio)sensing materials and integrated ionic circuits for seamless connection of human-machine interfaces., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

The recovery of gold from wastewater or electronic waste is significant due to its enormous value in a variety of fields. An amine-functionalized silsesquioxane (SQ)-based hybrid network (PCS-PAA) was successfully synthesized through the cost-effective, mild amine–ene reaction of acrylate-functionalized SQ with triaminoethylamine (TAA). Hydrophilic PCS-PAA helps to adsorb Au-(III) via the coordination with abundant heteroatoms (N and O). The adsorption capacity of PCS-PAA for Au-(III) reaches 647 mg/g within 30 min at room temperature and 1235 mg/g at 323 K, respectively. The Langmuir model is more suitable to describe the adsorption process, and the pseudo-second-order model well fits the adsorption kinetic. Surprisingly, most Au-(III) ions are in situ reduced to Au(0) particles, which are uniformly distributed on the surface of PCS-PAA. PCS-PAA-Au (PCS-PAA loaded with Au) can reduce 4-nitrophenol to 4-aminophenol with high catalytic activity. More interestingly, PCS-PAA can selectively adsorb Au-(III) from e-waste. This work provides a convenient and mild method to recover Au-(III) from wastewater or e-waste for multiple purposes. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane and organosilicon polymers, which are important classes of inorganic–organic hybrid materials, have emerged as effective adsorbents for the removal of contaminants from the wastewater. In this study, two hybrid materials polyhedral oligomeric silsesquioxane (1-(3-(polyhedraloligomericsilsesquioxane)propoxy)ethane-1,2-diol, POSS-diol) and organosilicon polymer (PGPTS) as adsorbents have been synthesized from 3-glycidyloxypropyltrimethoxysilane (GPTS) monomers by using basic catalyst tetrapropylammonium hydroxide (Pr4NOH(aq)) and acidic catalyst chlorotinbis[trimethylsilyl)]amide (SnCl(HMDS)), respectively. These hybrid materials POSS-diol and PGPTS were characterized by a few instrumental techniques such as NMR, FTIR, GPC, XRD, BET and then used in the removal of methylene blue (MB) dye from aqueous solutions. These hybrid silicon materials showed an exceptionally high degree of adsorption for MB dye compared to GPTS hydrolyzed with HCl(aq) (POSS-epoxide) and inorganic–organic hybrid materials of Al, Ti, and Zr. The reason for this high adsorption capacity of MB has been tried to be determined mechanically and discussed. [ABSTRACT FROM AUTHOR]

Thin films of 3-methacryloyloxypropylheptaisobutyl-T8-silsesquioxane (BuPOSSMA) were prepared by an electron-assisted (e-assist) deposition method. The film deposited by the conventional vapor deposition without the e-assist had a polycrystalline structure with a rough surface, whereas the e-assist deposition produced amorphous polymer thin films with a smooth surface. The deposited films were electrically insulating with a breakdown strength higher than 2 × 106 V cm−1. The polymerization of BuPOSSMA resulted in a decrease in the dielectric constant of the film. It was found that the deposition-polymerization achieved by the e-assist is effective in improving the thermal stability of the insulating and dielectric characteristics. [ABSTRACT FROM AUTHOR]

Carbon dioxide utilization presents an important and topical research topic. However, the performance of catalysts needed for CO 2 transformations does not achieve the necessary levels for their widespread application. To this end, we decided to study non-aqueous condensations providing amine-functionalized silica catalysts, possibly active in CO 2 -epoxide cycloaddition reaction. While non-hydrolytic sol-gel method is well-known for its efficiency in providing highly porous Lewis and Brønsted acid metallosilicates, here we show for the first time its application for the preparation of silica-based catalysts containing basic groups. First, the reaction conditions were screened to reproducibly obtain porous materials with preserved amine moieties. These were identified as follows: silicon tetraacetate and bridging tertiary amine silanes as precursors, toluene as a solvent, and temperature between 160 and 180 °C. In such a way, materials with up to 776 m2 g−1 and 1.58 cm3 g−1 were obtained in one-step process, without any template, after conventional drying step. Next, the amine-functionalized materials were tested in CO 2 -epoxide coupling providing cyclic organic carbonates with high selectivity (>99 %) and moderate activity (up to 86 % epichlorohydrin conversion after 1 h at 120 °C and 10 bar CO 2). The characterization of spent catalysts revealed a presence of cyclic organic carbonates at the catalyst surface as well as conversion of tertiary amine groups to quaternary ammonium moieties. [Display omitted] • Amine functionalized silica with up to 776 m2 g−1 and 1.58 cm3 g−1 by non-hydrolytic sol-gel. • Template-free and catalyst-free one-step synthetic process. • Materials active in the CO 2 cycloaddition on epichlorohydrin, styrene oxide, and 1,2-butylene oxide. • Quaternization of amine sites observed in spent catalysts. [ABSTRACT FROM AUTHOR]

The study aimed to determine the influence of shear stress during real-life industrial processes such as compression molding and injection molding to different cavities on the crystallization of the isotactic polypropylene nucleated with a novel silsesquioxane-based β-nucleating agent. Octakis(N2,N6-dicyclohexyl-4-(3-(dimethylsiloxy)propyl)naphthalene-2,6-dicarboxamido)octasilsesquioxane (SF-B01) is a highly effective nucleating agent (NA) based on the hybrid organic-inorganic silsesquioxane cage. The samples containing various amounts of the silsesquioxane-based and commercial iPP β-nucleants (0.01–0.5 wt%) were prepared by compression molding and injection molding, including forming in the cavities with different thicknesses. The study of the thermal properties, morphology, and mechanical properties of iPP samples allows for obtaining comprehensive information about the efficiency of silsesquioxane-based NA in shearing conditions during the forming. As a reference sample, iPP nucleated by commercial β-NA (namely N2,N6-dicyclohexylnaphthalene-2,6-dicarboxamide, NU-100) was used. The static tensile test assessed the mechanical properties of pure and nucleated iPP samples formed in different shearing conditions. Variations of the β-nucleation efficiency of the silsesquioxane-based and commercial nucleating agents caused by shear forces accompanying the crystallization process during forming were evaluated by differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). The investigations of changes in the mechanism of interactions between silsesquioxane and commercial nucleating agents were supplemented by rheological analysis of crystallization. It was found that despite the differences in the chemical structure and solubility of the two nucleating agents, they influence the formation of the hexagonal iPP phase in a similar way, taking into consideration the shearing and cooling conditions.

The present study proposes a novel application of humic substance–aminosilsesquioxane polyelectrolyte complexes (HS–ASQ) as dust suppressants. These complexes are synthesized through the reaction between humic substances (HS) and 3-aminopropyltriethoxysilane (APTES) in aqueous solution, resulting in the formation of active silanol groups that can bind to mineral surfaces and condense, forming gels. The HS–ASQ compositions were found to have a high sorption capacity for dust particles and could form coatings on their surface without cementing the dust, making them potentially useful for environmental applications. The viscosity of the HS–ASQ compositions can be controlled by adding carboxymethylcellulose (CMC), which also enhances their dust suppression abilities. Different compositions of HS–ASQ were synthesized by varying the proportions of APTES and CMC, and dust treated with these samples was assessed for its resistance to wind erosion using a laboratory-scale setup. Treatment with the HS–ASQ composition resulted in substantial reductions in PM10 and PM2.5 concentrations (particulate matter with aerodynamic diameters of 10 µm and 2.5 µm, respectively) of up to 77% and 85%, respectively, compared to the control.

In this review, we describe recent progress on stimuli‐responsive hybrid materials based on polyhedral oligomeric silsesquioxane (POSS) and their applications as a chemical sensor. In particular, we explain the unique functions originating from molecular assembly concerning POSS‐containing soft materials mainly from our studies. POSS has an inorganic cubic core composed of silicon‐oxygen (Si−O) bonds and organic substituents at each vertex. Owing to intrinsic properties of POSS, such as high thermal stability, rigidity, and low chemical reactivity, various robust hybrid materials have been developed. From the numerous numbers of POSS hybrids, we herein focus on the environment‐sensitive optical materials in which molecular assembly of POSS itself and functional units connected to POSS should be a key factor for expressing material properties. We also explain the mechanisms of chemical sensors originating from these stimuli‐responsive optical properties. Stimuli‐responsive excimer emission and pollutant detectors, nanoplastic sensors with the water‐dispersive POSS networks, trans fatty acid sensors, turn‐on luminescent sensors for aerobic condition and fluoride anion sensors are described. We also mention the mechanochromic polyurethane hybrids and the thermally‐durable mechanochromic luminescent materials. The roles of the unique optical properties from soft materials composed of rigid POSS, which doesn't have significant light‐absorption and emission properties in the visible region, are surveyed. [ABSTRACT FROM AUTHOR]

Purpose/Introduction: Silsesquioxanes with well-defined structures have been of great interest recently because of their superior properties. Among them, laddersiloxanes (ladder-type silsesquioxanes with defined structure) are less explored because step-by-step synthesis is usually necessary. In order to investigate the properties of laddersiloxanes, and apply these compounds as monomer precursors to high function materials, we prepared laddersiloxanes with reactive vinyl groups. Methods: The target compounds were obtained in a two-step reaction from commercially available alkoxysilanes, and total yields were 73–93 %. Three product stereoisomers were fully investigated by spectroscopic methods and structures were determined. Results: As an extension of our previous research on constructing new laddersiloxanes, we will describe here the synthesis, characterization, and functionalization of novel divinyl-substituted laddersiloxanes. Further transformation of all products proceeded smoothly, and extended laddersiloxanes were obtained by hydrosilylation. One isomer was isolated and the structure was determined unequivocally by X-ray analysis. Conclusions: The laddersiloxanes described here have two reactive vinyl groups at each end of the molecule. Various reactions including hydrosilylation, polymerization, or olefin metathesis are possible, thus these compounds can be potential monomers for highly functionalized materials. [ABSTRACT FROM AUTHOR]

In this study, novel lanthanide-containing double-decker polyhedral oligomeric silsesquioxanes (POSS) were prepared by combining the partially condensed TetraSilanolPhenyl POSS with terbium (Tb3+) and europium (Eu3+) ions. This open-cage POSS possesses four diametrically opposite silanol groups that are able to coordinate, under mild conditions, different luminescent ions through a simple corner-capping method. The two metal-containing POSS functionalized with Tb3+ and with an equimolar combination of Tb3+ and Eu3+ show a completely condensed structure with different luminescent properties. Their emission features depend on the chemical nature of the metal ions incorporated in the framework. An improved stokes shift was detected in the bimetallic compound containing both the Tb3+ and Eu3+ ions, promoted by the occurrence of a Tb3+→Eu3+ energy transfer mechanism. These characteristics identify this metal-functionalized silica platform as a potential candidate for the development of novel luminescent devices. [ABSTRACT FROM AUTHOR]

We report carbene insertion into Si−H bonds of polyhedral oligomeric silsesquioxanes (POSS) for the synthesis of highly functionalized siloxane nanomaterials. Dirhodium(II) carboxylates catalyze insertion of aryl‐diazoacetates as carbene precursors to afford POSS structures containing both ester and aryl groups as orthogonal functional handles for further derivatization of POSS materials. Four diverse and structurally varied silsesquioxane core scaffolds with one, three, or eight Si−H bonds were evaluated with diazo reactants to produce a total of 20 new POSS compounds. Novel diazo compounds containing a fluorinated octyl group and boron‐dipyrromethene (BODIPY) chromophore demonstrate the use of highly functionalized substrates. Transformations of aryl(ester)‐functionalized POSS compounds derived from this method are demonstrated, including ester hydrolysis and Suzuki–Miyaura cross‐coupling. [ABSTRACT FROM AUTHOR]

Four triazine‐functionalized silsesquioxane‐based hybrid porous polymers (TSHPPs) were synthesized by Heck reaction of octavinylsilsesquioxane (OVS) with brominated phenyl or thiophene substituted triazine monomers. These hybrid polymers offered good thermal stability, high specific surface areas (up to 555 m2 g−1), strong visible light absorption, and adjustable fluorescence properties. The materials showed high photocatalytic activity for the degradation of both acidic and basic dyes without additional oxidation agents or pH adjustments. Exposing to natural light, at a very low concentration of TSHPPs (0.2 mg mL−1), dyes with a concentration of up to 1000 ppm can be completely decolorized. After five consecutive iterations of degradation dyes, TSHPPs still showed good regenerability. This work provides an efficient method for the construction of photo‐responsive porous materials for solar‐to‐chemical energy conversion and demonstrates their potential as green and sustainable environment‐friendly catalysts. [ABSTRACT FROM AUTHOR]

Various fluoro polysilsesquioxanes (F-PSSQs) were prepared via acid-catalyzed hydrolysis and condensation of trimethoxysilanes carrying fluoro functionality, and characterized by NMR, GPC, TGA and DSC. The materials combined the low refractive indices (less than 1.4) and low dielectric constants (3–4 range at 100 kHz) associated with fluoropolymers with the high transmission, versatile cure and mechanical properties, and wettability desirable for optical materials deployed in multi-layer devices. In addition, the materials exhibited low glass transition temperatures (< -20 °C) and high thermal stability (5 % mass loss as high as 250 °C). UV-curable materials were prepared by using a second trimethoxysilane carrying (meth)acrylate functionality in combination with a trimethoxysilane carrying fluoro functionality. Molecular mass and viscosity were controlled by using disiloxanes as an end-cappers, and a low viscosity easy-to-process material was prepared (50 cps at 50 °C). [ABSTRACT FROM AUTHOR]

Silsesquioxane-based materials are garnering considerable attention due to their unique structural and electronic properties which enable use in diverse fields of study. In this article, we investigate a series of hybrid oligomeric materials comprising a silsesquioxane (SQ) backbone linked by conjugated organic cross-linkers and assess their photophysical properties in the steady state absorption and emission realms. Silsesquioxanes improve the thermal and photo stabilities of the organic components, offer enhancements in the molar extinction coefficients of absorption, and have a significant influence on their emission properties. We used Heck cross-coupling reactions to build oligomers with a vinyl/phenylSQ cage backbone linked with a series of different cross-linkers including 2,7-dibromo-9-fluorenone, 2,7-dibromo-9,9-dimethylfluorene, 1,4-dibromo-2,5-dimethoxybenzene, 2,5-dibromopyridine, 2,6-dibromopyridine, 2,3-dibromothiophene, 2,5-dibromothiophene, and 2,5- dibromothieno [3,2-b]thiophene. Each of these linkers showed reasonable conversion to oligomers and exhibited a wide array of fluorescence quantum yield and shifts in the absorption and emission spectra dependent on the variations in substitution position. We confined the study to explore the overall steady state spectral properties of these synthesized hybrid materials in their solution phases. Understanding the basic photophysical processes in these materials will pave the way towards their use in photovoltaic or electroluminescence applications. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxanes (POSSs) are a class of hybrid materials with a unique structure and properties originated from a combination of organic functional groups and inorganic silica core. Not well-defined synthesis process generally suffers from multistep, complex and especially time-consuming procedure from days to weeks and months. Consequently, in the present study, the effect of various parameters on the synthesis of octavinyl POSS (OV-POSS) nanostructure such as temperature, monomer concentration, reaction time, and rate of monomer addition are investigated. Finally, OV-POSS crystallization is produced under optimal condition through single-step hydrolytic condensation of vinyltrimethoxysilane (VTMS) with 72% yield and a high crystallinity (above 90%) during a reduced time interval of 5 h at 60 °C at a 20 μl.min-1 monomer addition rate. Morphology and size of the as-prepared samples are characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Also, the chemical structure is predicted using nuclear magnetic resonance (NMR), FTIR, and EDX.

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.

The synthesis and characterization of novel luminescent amorphous POSS-based polysilsesquioxanes (PSQs) with Tb3+ and Eu3+ ions directly integrated in the polysilsesquioxane matrix is presented. Two different Tb3+/Eu3+ molar ratios were applied, with the aim of disclosing the relationships between the nature and loading of the ions and the luminescence properties. Particular attention was given to the investigation of site geometry and hydration state of the metal centers in the inorganic framework, and of the effect of the Tb3+ → Eu3+ energy transfer on the overall optical properties of the co-doped materials. The obtained materials were characterized by high photostability and colors of the emitted light ranging from orange to deep red, as a function of both the Tb3+/Eu3+ molar ratio and the chosen excitation wavelength. A good energy transfer was observed, with higher efficiency displayed when donor/sensitizer concentration was lower than the acceptor/activator concentration. The easiness of preparation and the possibility to finely tune the photoluminescence properties make these materials valid candidates for several applications, including bioimaging, sensors, ratiometric luminescence-based thermometers, and optical components in inorganic or hybrid light-emitting devices.

This paper reports the synthesis and characterization of a silsesquioxane polymer based on a rigid silica inorganic core and 3-n-propyl(4-methylpyridinium) organic linker (Si-4Pic+Cl‒), an organic–inorganic hybrid material which showed great potential for the application as an adsorbent for 4-nitrophenol (4-NP), a hazardous organic compound. The silsesquioxane material was fully characterized by ATR-FTIR, solid-state 13C-NMR, and 29Si-NMR, TGA, potentiometric chloride titration and carbon, hydrogen, and nitrogen elemental analyses (CHN). The effect of pH, contact time on adsorption performance of Si-4Pic+Cl‒ to 4-NP and heterogeneous adsorption equilibrium were investigated systematically. The remarkable adsorption affinity of 4-NP onto Si-4Pic+Cl‒ obeys the Langmuir model and a π–π stacking interaction between adsorbent and adsorbate was proposed. Cycle rate experiments demonstrated that the ability to be recovered and reusable at least three times makes this silsesquioxane material a very promising adsorbent of noxious 4-NP in aqueous media. [ABSTRACT FROM AUTHOR]