Rational Design and Synthesis of Hybrid Porous Polymers Derived from Polyhedral Oligomeric Silsesquioxanes via Heck Coupling Reactions

An Ultrastable Porous Polyhedral Oligomeric Silsesquioxane/Tetraphenylthiophene Hybrid as a High-Performance Electrode for Supercapacitors

In this study, we synthesized three hybrid microporous polymers through Heck couplings of octavinylsilsesquioxane (OVS) with 2,5-bis(4-bromophenyl)-1,3,4-oxadiazole (OXD-Br₂), tetrabromothiophene (Th-Br₄), and 2,5-bis(4-bromophenyl)-3,4-diphenylthiophene (TPTh-Br₂), obtaining the porous organic–inorganic polymers (POIPs) POSS-OXD, POSS-Th, and POSS-TPTh, respectively. Fourier transform infrared spectroscopy and solid state ¹³C and ²⁹Si NMR spectroscopy confirmed their chemical structures. Thermogravimetric analysis revealed that, among these three systems, the POSS-Th POIP possessed the highest thermal stability (T₅: 586 °C; T₁₀: 785 °C; char yield: 90 wt%), presumably because of a strongly crosslinked network formed between its OVS and Th moieties. Furthermore, the specific capacity of the POSS-TPTh POIP (354 F g⁻¹) at 0.5 A g⁻¹ was higher than those of the POSS-Th (213 F g⁻¹) and POSS-OXD (119 F g⁻¹) POIPs. We attribute the superior electrochemical properties of the POSS-TPTh POIP to its high surface area and the presence of electron-rich phenyl groups within its structure.

A sulfur-containing fluorescent hybrid porous polymer for selective detection and adsorption of Hg2+ ions

A dual-function material, that is, a sulfur-containing fluorescent hybrid porous polymer, has been simply prepared and utilized to simultaneously detect and capture Hg2+ with high efficiency and selectivity.

Vinyl-Functionalized Janus Ring Siloxane: Potential Precursors to Hybrid Functional Materials

A vinyl-functionalized all-cis-tetrasiloxycyclotetrasiloxane [ViSi(OSiMe2H)O]4 (Vi = vinyl group) Janus precursor was prepared from potassium cyclotetrasiloxane silanolate. The Janus precursor was selectively modified at its dimethylhydrosilyl groups [-SiMe2H] via the Piers-Rubinsztajn reaction to obtain a family of new tetravinyl-substituted Janus rings [ViSi(OR')O]4 containing various functional groups in moderate yields. Remarkably, the tetravinyl groups on the structure remained intact after modification by the Piers-Rubinsztajn reaction. Since these synthesized compounds possess multiple functional groups (up to eight per molecule), they are potential precursors for advanced hybrid organic-inorganic functional materials.

Facile synthesis of transition metal containing polyhedral oligomeric silsesquioxane complexes with mesoporous structures and their applications in reducing fire hazards, enhancing mechanical and dielectric properties of epoxy composites

Transition metal (Co or Fe) containing polyhedral oligomeric silsesquioxane complexes (M@POSS-COOH) were prepared from octa carboxyl polyhedral oligomeric silsesquioxane (OC-POSS). The structures of OC-POSS and M@POSS-COOH were characterized by FT-IR, NMR, MALDI-TOF MS and XRD. Fe@POSS-COOH and Co@POSS-COOH possess mesoporous structures, whose Brunauer-Emmett-Teller surface areas (S_BET) are 58.7 m²/g and 46.3 m²/g, respectively. The remaining carboxyl groups of M@POSS-COOH that can react with epoxy groups along with the mesoporous structure increase the network strength of the epoxy resin (EP), and play a significant role in improving the mechanical properties, dielectric properties and thermal properties of the composites. Furthermore, the elemental composition of transition metal and silicon oxygen in the M@POSS-COOH structures significantly increases the amount of char residues of EP composites during the combustion of the material through elements catalysis and surface enrichment, which significantly reduces the toxic smoke density and fire hazards of EP composites. The structural and elemental merits of M@POSS-COOH significantly improve the overall performance of epoxy resin and occupy broad application space.

Porous silsesquioxane cage and porphyrin nanocomposites: sensing and adsorption for heavy metals and anions

A porous silsesquioxane cage/porphyrin nanocomposite was designed as a dual fluorescent probe for the sensing and adsorption of both heavy metal ions and anions.

New Porous Silicon-Containing Organic Polymers: Synthesis and Carbon Dioxide Uptake

The design and synthesis of new multifunctional organic porous polymers has attracted significant attention over the years due to their favorable properties, which make them suitable for carbon dioxide storage. In this study, 2-, 3-, and 4-hydroxybenzaldehyde reacted with phenyltrichlorosilane in the presence of a base, affording the corresponding organosilicons 1–3, which further reacted with benzidine in the presence of glacial acetic acid, yielding the organic polymers 4–6. The synthesized polymers exhibited microporous structures with a surface area of 8.174–18.012 m2 g−1, while their pore volume and total average pore diameter ranged from 0.015–0.035 cm3 g−1 and 1.947–1.952 nm, respectively. In addition, among the synthesized organic polymers, the one with the meta-arrangement structure 5 showed the highest carbon dioxide adsorption capacity at 323 K and 40 bar due to its relatively high surface area and pore volume.

Artificial Synthesis of Conjugated Microporous Polymers via Sonogashira-Hagihara Coupling

Amorphous network materials are becoming increasingly important with applications, for example, as supercapacitors, battery anodes, and proton conduction membranes. The design of these materials is hampered by the amorphous nature of the structure and sensitivity to synthetic conditions. Here, we show that through artificial synthesis, fully mimicking the catalytic formation cycle, and full synthetic conditions, we can generate structural models that can fully describe the physical properties of these amorphous network materials. This opens up pathways for the rational design where complex structural influences, such as the solvent and catalyst choice, can be taken into account.

Diphenylphosphine-Substituted Ferrocene/Silsesquioxane-Based Hybrid Porous Polymers as Highly Efficient Adsorbents for Water Treatment

The study describes the synthesis of two porous hybrid polymers (abbreviated as DPPF-HPP and DPPOF-HPP) from the Friedel-Crafts reaction of octavinylsilsesquioxane with 1,1'-bis(diphenylphosphine)ferrocene (DPPF) and 1,1'-bis(diphenylphosphine oxide)ferrocene (DPPOF), respectively. DPPF-HPP and DPPOF-HPP possess surface areas of about 890 and 780 m² g^-1, respectively, as well as similar pore structures of the coexisting micropores and mesopores. They are excellent materials for high adsorption of different dyes with adsorption capacities of 2280 mg g^-1 for Congo Red and 1440 mg g^-1 for Crystal Violet. DPPF-HPP also shows a strong affinity to adsorb Hg²⁺ ions (300 mg g^-1). These materials show no sign of degradation under repeated cycles and thus offer potential for wastewater treatment.

Porous networks based on iron(ii) clathrochelate complexes

Microporous networks based on boronate ester-capped iron(ii) clathrochelate complexes are described. The networks were obtained by covalent cross-linking of tetrabrominated clathrochelate complexes via Suzuki-Miyaura polycross-coupling reactions with diboronic acids, or by Sonogashira-Hagihara polycross-coupling of clathrochelate complexes with terminal alkyne functions and 1,3,5-tribromobenzene. The networks display permanent porosity with apparent Brunauer-Emmett-Teller surface areas of up to SABET = 593 m2 g-1. A clathrochelate complex based on an enantiopure dioximato ligand was used to prepare chiral networks. One of these networks was shown to preferentially absorb d-tryptophan over l-tryptophan.

Synthesis of Polycyclic and Cage Siloxanes by Hydrolysis and Intramolecular Condensation of Alkoxysilylated Cyclosiloxanes

The controlled synthesis of oligosiloxanes with well-defined structures is important for the bottom-up design of siloxane-based nanomaterials. This work reports the synthesis of various polycyclic and cage siloxanes by the hydrolysis and intramolecular condensation of monocyclic tetra- and hexasiloxanes functionalized with various alkoxysilyl groups. An investigation of monoalkoxysilylated cyclosiloxanes revealed that intramolecular condensation occurred preferentially between adjacent alkoxysilyl groups to form new tetrasiloxane rings. The study of dialkoxy- and trialkoxysilylated cyclotetrasiloxanes revealed multistep intramolecular condensation reactions to form cubic octasiloxanes in relatively high yields. Unlike conventional methods starting from organosilane monomers, intramolecular condensation enables the introduction of different organic substituents in controlled arrangements. So-called Janus cubes have been successfully obtained, that is, Ph₄ R₄ Si₈ O₁₂ , in which R=Me, OSiMe₃ , and OSiMe₂ Vi (Vi=vinyl). These findings will enable the creation of siloxane-based materials with diverse functions.

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

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

Hyperbranched Polysiloxanes Based on Polyhedral Oligomeric Silsesquioxane Cages with Ultra-High Molecular Weight and Structural Tuneability

Hyperbranched siloxane-based polymers with ultra-high molecular weight were synthesized by the Piers–Rubinsztajn reaction between octakis(dimethylsiloxy) octasilsesquioxane with different dialkoxysilanes, using tris(pentafluorophenyl) borane as the catalyst. The origin of the high molecular weight is explained by the high reactivity of the catalyst and strain energy of isolated small molecule in which all eight silane groups close into rings on the sides of a single cubic cage. The structural tuneability was further demonstrated by use of methyl(3-chloropropyl)diethoxysilane, which generates a polymer with similar ultra-high molecular weight. Introduction of phosphonate groups through the chloropropyl sites later leads to functionalized polymers which can encapsulate various transition metal nanoparticles.

New Eco-Friendly Phosphorus Organic Polymers as Gas Storage Media

Three phosphate esters 1⁻3 were successfully synthesized from the reaction of 2-, 3- and 4-hydroxybenzaldehyde with phosphoryl chloride. Reactions of 1⁻3 with benzidine in the presence of glacial acetic acid gave the corresponding novel phosphorus organic polymers 4⁻6 containing the azomethane linkage. The structures of the synthesized compounds were confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance and elemental analysis. Interesting physiochemical properties for the polymeric materials 4⁻6 were observed using a combination of several techniques such as gel permeation chromatography, scanning electron microscopy, Brunauer⁻Emmett⁻Teller and nitrogen adsorption⁻desorption isotherm, Barrett⁻Joyner⁻Halenda and H-sorb 2600 analyzer. The mesoporous polymers 4⁻6 exhibit tunable porosity with Brunauer⁻Emmett⁻Teller surface area (SABET = 24.8⁻30 m²·g⁻1), pore volume (0.03⁻0.05 cm³·g⁻1) and narrow pore size distribution, in which the average pore size was 2.4⁻2.8 nm. Polymers 4⁻6 were found to have high gas storage capacity and physico-chemical stability, particularly at a high pressure. At 323 K and 50 bars, polymers 4⁻6 have remarkable carbon dioxide uptake (up to 82.1 cm³·g⁻1) and a low hydrogen uptake (up to 7.4 cm³·g⁻1). The adsorption capacity of gasses for polymer 5 was found to be higher than those for polymers 4 and 6.

Fluorescence-Tuned Polyhedral Oligomeric Silsesquioxane-Based Porous Polymers

Two series of new polyhedral oligomeric silsesquioxane (POSS)-based fluorescent hybrid porous polymers, HPP-1 and HPP-2, have been prepared by the Heck reaction of octavinylsilsesquioxane with 2,2',7,7'-tetrabromo-9,9'-spirobifluorene and 1,3,6,8-tetrabromopyrene, respectively. Three sets of reaction conditions were employed to assess their effect on fluorescence. These materials exhibit tunable fluorescence from nearly no fluorescence to bright fluorescence both in the solid state and dispersed in ethanol under UV light irradiation by simply altering the reaction conditions. We speculated that the difference may be attributable to the fluorescence quenching induced by Et3 N, P(o-CH3 Ph)3 , and their hydrogen bromide salts employed in the reactions. This finding could give valuable suggestions for the construction of porous polymers with tunable/controllable fluorescence, especially those prepared by Heck and Sonogashira reactions in which these quenchers are used as organic bases or co-catalysts. In addition, the porosities can also be tuned, but different trends in porosity have been found in these two series of polymers, which suggests that various factors should be carefully considered in the preparation of porous polymers with tunable/controllable porosity. Furthermore, HPP-1 c showed moderate CO2 uptake and fluorescence that was efficiently quenched by nitroaromatic explosives, thereby indicating that these materials could be utilized as solid absorbents for the capture and storage of CO2 and as sensing agents for the detection of explosives.

Amine post-functionalized POSS-based porous polymers exhibiting simultaneously enhanced porosity and carbon dioxide adsorption properties

We provide a possibility for post-synthetic amine functionalization of porous polymers exhibiting enhanced CO₂ capacity and selectivity without compromising the porosity.

A facile approach to prepare a microporous polycarbazole P-tetra(4-(N-carbazolyl)phenyl)silane network with high CO2 storage and separation properties

A facile approach to prepare a microporous polycarbazole P-TCzPhSi network by FeCl₃ oxidative polymerization reaction.

Construction of bimodal silsesquioxane-based porous materials from triphenylphosphine or triphenylphosphine oxide and their size-selective absorption for dye molecules

Phosphorus-containing porous materials from octavinylsilsesquioxane possessed unique bimodal structure and exhibited an excellent size-selective absorption for dye molecules.

Synthesis of aromatic functionalized cage-rearranged silsesquioxanes (T8, T10, and T12) via nucleophilic substitution reactions

Organic-inorganic hybrid nano-building blocks of aromatic nitro-, aldehyde-, and bromo-functionalized polyhedral oligomeric silsesquioxanes were easily prepared through nucleophilic substitutions, starting from the reactions between octakis(3-chloropropyl)octasilsesquioxane and phenoxide derivatives. These phenoxide anions not only supply the substitution functions to a silsesquioxane cage, but can also induce a cage-rearrangement leading to the formation of octa-, deca-, and dodecahedral silsesquioxane cages.

A novel pH-responsive POSS-based nanoporous luminescent material derived from brominated distyrylpyridine and octavinylsilsesquioxane

A novel porous material is prepared by octavinylsilsesquioxane and brominated distyrylpyridine via the Heck coupling reaction, which exhibits an excellent pH-responsive property in the pH range from 1 to 4.

Octavinylsilsesquioxane-based luminescent nanoporous inorganic–organic hybrid polymers constructed by the Heck coupling reaction

A class of luminescent nanoporous inorganic–organic hybrid polymers has been synthesized by the Heck coupling of octavinylsilsesquioxane with aromatic bromide monomers. The resulting materials exhibit porous and luminescent features, and show picric acid sensing behaviour.

Construction and electronic properties of carbon nanotube hybrids with conjugated cubic silsesquioxane

Hierarchical zero-dimensional cubic silsesquioxane/one-dimensional SWNT hybrids provided excellent charge transfer and synergistic effects compared to both SWNTs and OASQ.

POSS-based luminescent porous polymers for carbon dioxide sorption and nitroaromatic explosives detection

Luminescent porous polymers based on octavinylsilsequioxane and triphenylamine units show tunable porosity and luminescence, a moderate uptake of CO₂ and high sensitivity for TNT.

Constructing hybrid porous polymers from cubic octavinylsilsequioxane and planar halogenated benzene

Hybrid porous polymers derived from cubic octavinylsilsequioxane and planar halogenated benzene monomers exhibit high thermal stability, tunable porosities and potential applications in carbon dioxide storage.

Facile construction of hybrid polystyrene with a string of lantern shape from monovinyl-substituted POSS and commercial polystyrene via Friedel–Crafts reaction and its properties

Hybrid polystyrene was easily prepared from monovinyl-substituted POSS and commercial polystyrene (PS)viaa straightforward Friedel–Crafts reaction.