Porous Silsesquioxane-Imine Frameworks as Highly Efficient Adsorbents for Cooperative Iodine Capture

3D Silsesquioxane Cage-Based Covalent Organic Frameworks Enabling Efficient Ion Transport in Quasi-Solid-State Lithium Metal Batteries

The resurgence of lithium metal batteries (LMBs) necessitates advancements in electrolyte engineering to regulate ion transport and manipulate interfacial characteristics. Noteworthy strategies encompass the development of high-efficiency lithium-ion conductors for quasi-solid-state composite electrolytes. In this context, two crystalline 3D COFs are presented that are thoughtfully designed by selecting decasilsesquioxane (T10) cage building blocks and linear linkers to open up efficient ion-conducting pathways. The cage silsesquioxane-knotted COFs (CSQ-COFs) feature densely interconnected pore channels and a multimodal pore size distribution, which gives them the potential to function as ionic conductors. In addition, the dissociation of electrolyte salts by the silsesquioxane framework, along with the strong adsorption of anions, synergistically enhances ion transport. The coin cell assembled with CSQ-COF displays an ionic conductivity of 0.727 mS cm-1 at 80 °C, an Ea of 0.12 eV, and tLi+ of 0.83. Therefore, Li symmetrical cell demonstrates excellent Li plating/stripping behaviors for 600 h under 0.5 mA cm-2. The Li/LiFePO4 cell containing the CSQ-COF solid-state electrolyte delivers an initial discharge capacity of ≈159.6 mAh g-1 at a rate of 0.5 C at room temperature with excellent capacity retention after 150 cycles. This work provides a novel insight on the development of 3D COF ionic conductors.

Excited State Dynamics Govern Emission Properties of Unique Silsesquioxane-Salphen-Based Zinc Compounds

This study aims to develop a synthetic protocol for preparing salphen-based hybrid compounds with silsesquioxane T8 cages anchored at the molecule's periphery. Three types of coordination compounds featuring κ4-N2O2-donating atoms were obtained via a sequence of reactions. These compounds differ in the arene linker between the salphen and silsesquioxane fragments. An individual synthetic pathway was developed for the preparation of aldehydes, followed by a tailored strategy for the synthesis of the final complexes employing both solution-based and mechanochemical methods in the solid state. The latter represents a novel technique in silsesquioxane chemistry. The newly designed ligands were used for the coordination of Zn2+ ions to evaluate their ligation properties and to determine the photophysical properties of the resulting complexes in comparison to their bare ligand molecules. Using absorption and emission spectroscopy, combined with advanced time-resolved spectroscopic methods, we demonstrated that the photochemical efficiency of these compounds is influenced by their tendency to aggregate in solution, which positively affects their photophysical properties and enhances their potential for photodynamic therapy (PDT). Additionally, we explored the ability of these complexes to generate singlet oxygen (1O2) depending on the architecture of the designed ligands. The results indicate that the excited state dynamics plays a crucial role in determining the emission properties of the studied compounds, which may have significant implications for their applications in medicine and materials science.

Catalyzing Knoevenagel Condensation and Radioiodine Sequestration with Tuned Porous Organic Polymers to Decipher the Role of Surface Area, Pore Volume, and Heteroatom

The impact of surface area, pore volume, and heteroatom type on the performance of porous organic polymers (POPs) in various applications remains unclear. To investigate this, three isoreticular POPs were employed having one common building block, resulting in varying surface areas, pore volumes, and heteroatom compositions. This study aimed to establish a correlation between the structural features of POPs (surface area, pore volume, and heteroatom type) with their adsorption capacity, and catalytic efficiency. To explore this relationship, the Knoevenagel condensation reaction was used as a model system, testing various substituted aldehydes to further validate our findings. Additionally, the capture of radioactive iodine vapor at 75 °C was simulated to examine the correlation with adsorption capacity, comparing the gravimetric iodine uptake capacity of each POP to gain insights into this relationship.

Amphiphilic Azo-Functionalized Polyhedral Oligomeric Silsesquioxane; Synthesis and Photo-Switched Efficient Phase Transfer via Host-Guest Encapsulation

A new amphiphilic azo-functionalized polyhedral oligomeric silsesquioxane (POSS) derivative was synthesized by functionalizing octa(3-aminopropyl)silsesquioxane (OAS-POSS) with 4-((4-(dodecyloxy)phenyl)diazenyl)benzoic acid, affording a hydrophilic amino POSS head and hydrophobic dodecyl tail with a diphenyl-azo connector. Prepared amphiphilic azo-functionalized POSS (azo-POSS) exhibited high ability for encapsulation and transferring cationic dyes into the organic phase by vigorously mixing with aqueous solutions of each dye. The photo-controlled encapsulating properties of the synthesized phase transfer reagent was studied using cationic dyes, such as methylene blue (MB), crystal violet (CV) and thymol blue in acidic conditions. Results showed more than 95 % encapsulation of MB. However, no considerable encapsulation was shown in the case of anionic dyes such as eriochrome black T (EBT) and thymol blue in alkaline solutions. By trans/cis isomerization of the azo moiety of the phase transfer reagent by UV irradiation (365 nm), the amount of dye encapsulation was decreased, which could be attributed to the formation of cis isomer that led to the folding of the dodecyl alkyl tail on the POSS moiety, and therefore prevent to lay the 3-aminopropyl moieties of POSS head to the water/DCM interface to adsorb and encapsulate MB molecules.

Iodine and Nickel Ions Adsorption by Conjugated Copolymers Bearing Repeating Units of Dicyclopentapyrenyl and Various Thiophene Derivatives

The synthesis of three conjugated copolymers TPP1-3 was carried out using a palladium-catalyzed [3+2] cycloaddition polymerization of 1,6-dibromopyrene with various dialkynyl thiophene derivatives 3a-c. The target copolymers were obtained in excellent yields and high purity, as confirmed by instrumental analyses. TPP1-3 were found to divulge a conspicuous iodine adsorption capacity up to 3900 mg g-1, whereas the adsorption mechanism studies revealed a pseudo-second-order kinetic model. Furthermore, recyclability tests of TPP3, the copolymer which revealed the maximum iodine uptake, disclosed its efficient regeneration even after numerous adsorption-desorption cycles. Interestingly, the target copolymers proved promising nickel ions capture efficiencies from water with a maximum equilibrium adsorption capacity (qe) of 48.5 mg g-1.

Synthesis of Iron(II) Clathrochelate-Based Poly(vinylene sulfide) with Tetraphenylbenzene Bridging Units and Their Selective Oxidation into Their Corresponding Poly(vinylene sulfone) Copolymers: Promising Materials for Iodine Capture

The development of a simple and efficient synthetic methodology to engineer functional polymer materials for gas adsorption is necessary due to its relevance for various applications. Herein, we report the synthesis of metalorganic poly(vinylene sulfide) copolymers CTP1-3 with iron(II) clathrochelate of various side groups connected by tetraphenylbenzene units. CTP1-3 were subsequently oxidized into their respective poly(vinylene sulfone) copolymers CTP4-6 under green reaction conditions. The target copolymers CTP1-6 were characterized using various instrumental analysis techniques. Examination of the iodine adsorption properties of the copolymers revealed high iodine uptake properties, reaching 2360 mg g−1 for CTP2, and whose reusability tests proved its efficient regeneration, thus proving the importance of iron(II) clathrochelate polymers in iodine capture.

Efficient and simultaneous capture of iodine and methyl iodide achieved by a covalent organic framework

Radioactive molecular iodine (I₂) and organic iodides, mainly methyl iodide (CH₃I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I₂ and CH₃I simultaneously. Here we demonstrate that the I₂ adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH₃I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I₂ and CH₃I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH₃I adsorption capacity (1.53 g·g⁻¹ at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I₂ and 50 ppm of CH₃I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g⁻¹), surpassing various benchmark adsorbents. This work deepens the understanding of I₂/CH₃I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.

Radioactive molecular iodine (I₂) and methyl iodide (CH₃I) coexist in the off-gas stream of nuclear power plants at low concentrations and only few adsorbents can effectively adsorb low-concentration I₂ and CH₃I simultaneously. Here, the authors demonstrate simultaneous capture of I₂ and CH₃I at low concentrations by exploiting different adsorptive sites in a covalent organic framework.

Iodine adsorption and electrochemical double-layer capacitor characteristics of activated carbon prepared from low-cost biomass

The efficient adsorption application and electric double-layer capacitor material with low-cost biomass-based activated carbon materials have been quite common recently. In this study, chestnut shell-based activated carbons were produced by chemical activation. ZnCl₂, H₃PO₄, and KOH agents were used for chemical activation. The obtained activated carbon, iodine adsorption from aqueous solutions, and its use as an electro capacitor were investigated. The scanning electron microscope, nitrogen adsorption/desorption, and Fourier transform infrared spectroscopy were used for characterization. The values of surface area and iodine adsorption capacity of the chestnut shell-based activated carbon are 1544 m² g^-1 and 1525 mg g^-1. As a result, a specific capacitance of 97 Fg^-1 with chestnut shell-based activated carbon was obtained in a 1 M KCl electrolyte for the electrochemical double-layer capacitor. This study shows that activated carbon based on the chestnut shell can be used both as an electrochemical energy storage material and as an adsorbent in iodine adsorption.

Affimer Tagged Cubosomes: Targeting of Carcinoembryonic Antigen Expressing Colorectal Cancer Cells Using In Vitro and In Vivo Models

Nanomedicines, while having been approved for cancer therapy, present many challenges such as low stability, rapid clearance, and nonspecificity leading to off-target toxicity. Cubosomes are porous lyotropic liquid crystalline nanoparticles that have shown great premise as drug delivery vehicles; however, their behavior in vivo is largely underexplored, hindering clinical translation. Here, we have engineered cubosomes based on the space group Im3m that are loaded with copper acetylacetonate as a model drug, and their surfaces are functionalized for the first time with Affimer proteins via copper-free click chemistry to actively target overexpressed carcinoembryonic antigens on LS174T colorectal cancer cells. Unlike nontargeted cubosomes, Affimer tagged cubosomes showed preferential accumulation in cancer cells compared to normal cells not only in vitro (2D monolayer cell culture and 3D spheroid models) but also in vivo in colorectal cancer mouse xenografts, while exhibiting low nonspecific absorption and toxicity in other vital organs. Cancerous spheroids had maximum cell death compared to noncancerous cells upon targeted delivery. Xenografts subjected to targeted drug-loaded cubosomes showed a 5-7-fold higher drug accumulation in the tumor tissue compared to the liver, kidneys, and other vital organs, a significant decrease in tumor growth, and an increased survival rate compared to the nontargeted group. This work encompasses the first thorough preclinical investigation of Affimer targeted cubosomes as a cancer therapeutic.

Covalent Triazine Frameworks Based on the First Pseudo-Octahedral Hexanitrile Monomer via Nitrile Trimerization: Synthesis, Porosity, and CO2 Gas Sorption Properties

Herein, we report the first synthesis of covalent triazine-based frameworks (CTFs) based on a hexanitrile monomer, namely the novel pseudo-octahedral hexanitrile 1,4-bis(tris(4'-cyano-phenyl)methyl)benzene 1 using both ionothermal reaction conditions with ZnCl2 at 400 °C and the milder reaction conditions with the strong Brønsted acid trifluoromethanesulfonic acid (TFMS) at room temperature. Additionally, the hexanitrile was combined with different di-, tri-, and tetranitriles as a second linker based on recent work of mixed-linker CTFs, which showed enhanced carbon dioxide captures. The obtained framework structures were characterized via infrared (IR) spectroscopy, elemental analysis, scanning electron microscopy (SEM), and gas sorption measurements. Nitrogen adsorption measurements were performed at 77 K to determine the Brunauer-Emmett-Teller (BET) surface areas range from 493 m2/g to 1728 m2/g (p/p0 = 0.01-0.05). As expected, the framework CTF-hex6 synthesized from 1 with ZnCl2 possesses the highest surface area for nitrogen adsorption. On the other hand, the mixed framework structure CTF-hex4 formed from the hexanitrile 1 and 1,3,5 tricyanobenzene (4) shows the highest uptake of carbon dioxide and methane of 76.4 cm3/g and 26.6 cm3/g, respectively, at 273 K.

A Pressure Swing Approach to Selective CO2 Sequestration Using Functionalized Hypercrosslinked Polymers

Functionalized hypercrosslinked polymers (HCPs) with surface areas between 213 and 1124 m²/g based on a range of monomers containing different chemical moieties were evaluated for CO₂ capture using a pressure swing adsorption (PSA) methodology under humid conditions and elevated temperatures. The networks demonstrated rapid CO₂ uptake reaching maximum uptakes in under 60 s. The most promising networks demonstrating the best selectivity and highest uptakes were applied to a pressure swing setup using simulated flue gas streams. The carbazole, triphenylmethanol and triphenylamine networks were found to be capable of converting a dilute CO₂ stream (>20%) into a concentrated stream (>85%) after only two pressure swing cycles from 20 bar (adsorption) to 1 bar (desorption). This work demonstrates the ease with which readily synthesized functional porous materials can be successfully applied to a pressure swing methodology and used to separate CO₂ from N₂ from industrially applicable simulated gas streams under more realistic conditions.

A silsesquioxane-porphyrin-based porous organic polymer as a highly efficient and recyclable absorbent for wastewater treatment

Effective capture of pollutants from wastewater is crucial for protecting the environment and human health. An azo-based porous organic polymer (AzoPPOP) containing porphyrin and inorganics cage polyhedral oligomeric silsesquioxane units was synthesized via a catalyst-free coupling reaction. Results showed that AzoPPOP possess a high surface area, a hierarchically porous structure, good thermal stability, abundant adsorption sites, and an electronegative nature. Based on these properties, AzoPPOP had an extremely high adsorption capacity (1357.58 mg g^-1) for RhB, a fast adsorption rate, and good selectivity. Study of the mechanism revealed that in addition to electrostatic interactions, the high specific surface area, existence of -NH₂, and the strong π-π interaction between AzoPPOP and RhB also play important roles for the adsorption of RhB. AzoPPOP also displayed excellent adsorption properties for heavy metal ions (230.45, 192.24 and 162.11 mg g^-1 for Ag⁺, Hg²⁺, and Pb²⁺, respectively). More importantly, simulation of the purification experiment of waste water and the recycling regeneration experiment revealed that AzoPPOP has good high-level recyclability and could remove multi-pollutants in one pass through a simple adsorption column.

Enrichment and Quantitative Determination of Free 3,5- Diiodothyronine, 3',5'-Diiodothyronine, and 3,5-Diiodothyronamine in Human Serum of Thyroid Cancer by Covalent Organic Hyper Cross-linked Poly-ionic Liquid

The incidence of thyroid cancer is increasing worldwide. So far, still no non-invasive clinical test biomarkers were developed for the diagnosis of thyroid cancer. The diiodothyronines (T2s) are precursors and metabolites of thyroid hormone (T4). Some reports predict that T2s may be associated with several thyroid diseases, especially the thyroid cancer. Detecting free T2s in human serum may help the diagnosis of thyroid cancer. However, few works have reported the detection of T2s due to their trace amounts. Here we developed a novel hyper organic cross-linked poly ionic liquid (PIL) material for the enrichment of three main compounds in T2s family, including 3,5- diiodothyronine (3,5-T2), 3',5'-diiodothyronine (3',5'-T2), and 3,5-diiodothyronamine (3,5-T2AM). This PIL material provided specific enrichment superiority for three T2s. After enrichment, the signal intensity of 3,5-T2, 3',5'-T2, and 3,5-T2AM increased 14, 132 and 1.6 folds, respectively, with LOQ of 76, 87, and 107 fM, respectively. Finally, we successfully applied PIL material coupled with HPLC-ESI-MS/MS in enrichment and quantitative determination of free 3,5-T2, 3',5'-T2, and 3,5-T2AM in human serum of 45 thyroid cancer patients and 15 healthy people. We also used free thyroid hormone (FT4) as the calibration reference to eliminate individual differences. We found that the levels of 3,5-T2 (P < 0.001), and 3',5'-T2 (P = 0.001) in patients with thyroid cancer were significantly higher than those in healthy people. Additionally, we further investigated the power of different T2 thyroid hormones divided FT4 to classify thyroid cancer patients and healthy people. And 3,5-T2/FT4 had the highest classification performance for discriminating thyroid cancer patients from healthy people at certain threshold, indicating that 3,5-T2/FT4 in human serum can act as potential biomarkers for "non-invasive" clinical diagnosis of thyroid cancer.

Cationic Nonporous Macrocyclic Organic Compounds for Multimedia Iodine Capture

Over the past two decades, progress in chemistry has generated various types of porous materials for removing iodine (¹²⁹ I or ¹³¹ I) that can be formed during nuclear energy generation or nuclear waste storage. However, most studies for iodine capture are based on the weak host-guest interactions of the porous materials. Here, we present two cationic nonporous macrocyclic organic compounds, namely, MOC-1 and MOC-2, in which 6I^- and 8I^- were as counter anions, for highly efficient iodine capture. MOC-1 and MOC-2 were formed by reacting 1,1'-diamino-4,4'-bipyridylium di-iodide with 1,2-diformylbenzene or 1,3-diformylbenzene, respectively. The presence of a large number of I^- anions results in high I₂ affinity with uptake capacities up to 2.15 g ⋅ g^-1 for MOC-1 and 2.25 g ⋅ g^-1 for MOC-2.

Conjugated microporous polymers using a copper-catalyzed [4 + 2] cyclobenzannulation reaction: promising materials for iodine and dye adsorption

A new design strategy is disclosed to synthesize conjugated microporous polymers using a Cu-catalyzed [4 + 2] cyclobenzannulation reaction. The polymers reveal BET surface areas up to 794 m² g⁻¹ and promising uptake of iodine and methylene blue.

Mono-substituted cage-like silsesquioxanes bound by trifunctional acyl chloride as a multi-donor N,O-type ligand in copper(ii) coordination chemistry: synthesis and structural properties

In this paper, we report on the synthesis of novel copper(ii) complexes containing a multi-donor N,O-type ligand based on mono-substituted cage-like silsesquioxanes bound by trifunctional acyl chloride.

Easily Constructed Imine-Bonded COFs for Iodine Capture at Ambient Temperature

Volatile radionuclides generated during the nuclear fission process, such as iodine, pose risks to public safety and cause the threat of environmental pollution. Covalent organic framework (COF) materials have a controlled pore structure and a large specific surface area and thus demonstrate great opportunities in the field of radioactive iodine adsorption. However, the harsh synthetic conditions and the weak binding capability toward iodine have significantly restricted the applications of COFs in iodine adsorption. Here, we demonstrate a facile way to prepare a series of stable C-N-linked COFs with high efficiency to capture radioactive iodine species. Large-scale synthesis can be conducted by the aldol condensation reaction at room temperature. The resulting COFs have a large surface area and a strong resistance to acid, base, and water. Moreover, all types of COFs show high iodine adsorption, up to 2.6 g/g (260% in mass), owing to the large surface area and the functional groups in COFs. They not only absorb conventional I2 molecular but also ionic state (I3 - and I+) iodine species. Theoretical calculations are further performed to understand the relationship between different iodine species and the functional groups of all COFs, offering the mechanisms underlying the potent adsorption abilities of COFs.

Zinc Imine Polyhedral Oligomeric Silsesquioxane as a Quattro-Site Catalyst for the Synthesis of Cyclic Carbonates from Epoxides and Low-Pressure CO2

In the present research, the synthesis, spectroscopic characterization, and structural investigations of a unique Zn^II complex of imine-functionalized polyhedral oligomeric silsesquioxane (POSS) is designed, and hereby described, as a catalyst for the synthesis of cyclic carbonates from epoxides and CO₂. The uncommon features of the designed catalytic system is the elimination of the need for a high pressure of CO₂ and the significant shortening of reaction times commonly associated with such difficult transformations like that of styrene oxide to styrene carbonate. Our studies have shown that imine-POSS is able to chelate metal ions like Zn^II to form a unique coordination complex. The silsesquioxane core and the hindrance of the side arms (their steric effect) influence the construction process of the homoleptic Zn₄@POSS-1 complex. The compound was characterized in solution by NMR (¹H, ¹³C, ²⁹Si), ESI-MS, UV/Vis spectroscopy and in the solid state by thermogravimetric/differential thermal analysis (TG-DTA), elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), cross-polarization magic angle spinning (CP MAS) NMR (¹³C, ²⁹Si) spectroscopy, and X-ray crystallography.

Highly selective anchoring silver nanoclusters on MOF/SOF heterostructured framework for efficient adsorption of radioactive iodine from aqueous solution

A series of Ag-modified MOF/SOF heterostructured framework adsorbents (Ag-MSHC) with strong binding of iodine were prepared by anchoring silver nanoclusters on MOF/SOF heterostructured framework (MSHC). Morphological transformation process of six novel Ag-MSHC adsorbents can be realized by tailoring the molar ratio of Fe³⁺, TMA (1,3,5-Tricarboxybenzen) and MA (melamine), finally resulting in a combination of MOFs (metal-organic frameworks) and SOFs (supramolecular organic framework). Among six adsorbents, Ag-MSHC-6 exhibited an extremely strong affinity towards I^-, whereas the maximum adsorption capacity of I^- reaches 771.6 mg/g. An increased tendency of I^- sorption occurred from Ag-MSHC-1 to Ag-MSCH-6 when the molar ratio of Fe³⁺ gradually decreased because the content of Fe³⁺ in topological structure of Ag-MSHC can hinder the incorporation of silver nanoclusters into Ag-MSHC and further influences the irreversible interactions between Ag₂O and I^-. Besides, FT-IR, XPS, TGA and SEM were used to discuss the microstructures and chemical composition of MSHC and Ag-MSHC, and we also performed batch adsorption experiments to demonstrate the iodine sorption performance and mechanism by Ag-MSHC. Taking advantage of this combination of MOFs and SOFs, high degree of doping of silver nanoclusters as well as its strong binding ability of iodine, Ag-MSHC can be considered as a superior adsorbent for radioactive iodine extraction.

Nanocage-Based InIII{TbIII}2-Organic Framework Featuring Lotus-Shaped Channels for Highly Efficient CO2 Fixation and I2 Capture

The exquisite combination of independent 3p [In(CO₂)₄] units and 4f [Tb₂(CO₂)₈] clusters in the presence of the designed hexatopic 2,4,6-tri(2,4-dicarboxyphenyl)pyridine ligand engenders one peculiar nanocaged In(III){Tb(III)}₂-organic framework: ({(Me₂NH₂)[InTb₂(HTDP)₂]·3DMF·3H₂O}_n, designated as NUC-5), which features dual types of lotus-shaped channels along the [100] and [110] axes with related node windows of 5.3 × 6.8 and 12.1 × 9.2 Ų, respectively. To the best of our knowledge, except several coexisted 3p-4f In/Ln clusters of {In₃Ln}- and {In₃Ln₂}-based metal-organic frameworks (MOFs), NUC-5 is one novel type of In/Ln heterometallic framework. In addition, its topology was an unprecedented 3D TAYZIC net with a Schläfli symbol of {4.⁴6²}{4.⁵6⁵}₂{4.⁶6.⁸8}. Moreover, activated NUC-5 is proved to be one efficient adsorbent for CO₂ and one recycled cycloaddition catalyst for the transformation of epoxides into related carbonates with high yields under mild conditions. Furthermore, the excellent reversible sorption performance for I₂ in the volatilization phase or in cyclohexane solution with a maximum adsorption capacity of 609.1 mg/g (3.75 iodine molecules per unit cell) makes NUC-5 a promising adsorbent for radioactive products of ¹²⁹I and ¹³¹I in the field of nuclear industry. This study provides one synthetic strategy that the original nature of MOFs could be enhanced by introducing some specific function-prompted inorganic subunits with the aid of predesigned supporting ligands.

Fluorescent conjugated microporous polymers containing pyrazine moieties for adsorbing and fluorescent sensing of iodine

Two kinds of fluorescent conjugated microporous polymers containing pyrazine moieties were prepared by the polymerization reaction of 2,5-di-triphenylamine-yl-pyrazine (DTPAPz) and N,N,N',N'-tetrapheny-2,5-(diazyl) pyrazine (TDPz) with 2,4,6-trichloro-1,3,5-triazine (TCT) through Friedel-Crafts reaction using the methanesulfonic acid as a catalysts. Both CMPs have high thermal stability and decomposition temperature reaches above 596 and 248 °C under nitrogen atmosphere, respectively. By right of porous morphology and electron-donating nitrogen, as well as electron-rich π-conjugated structures, the adsorption performance for iodine vapor on the CMPs is very excellent, which can reach 441% and 312%. In addition, fluorescence studies showed that the two CMPs exhibited high fluorescence sensitivity to electron-deficient iodine, o-nitrophenol (o-NP), and picric acid (PA) via fluorescence quenching.

Cage-like silsesquioxanes-based hybrid materials

Cage-like silsesquioxanes are considered to be ideal and versatile building blocks of hybrid materials due to their unique structures and excellent performance. This Perspective highlights recent advances in the field of cage-like silsesquioxane-based hybrid materials, ranging from monomer functionalization and materials preparation to application. The existing issues are reviewed and the challenges and prospects in this field are also discussed for further development and exploitation.

Porous Aromatic Frameworks (PAFs)

Porous aromatic frameworks (PAFs) represent an important category of porous solids. PAFs possess rigid frameworks and exceptionally high surface areas, and, uniquely, they are constructed from carbon-carbon-bond-linked aromatic-based building units. Various functionalities can either originate from the intrinsic chemistry of their building units or are achieved by postmodification of the aromatic motifs using established reactions. Specially, the strong carbon-carbon bonding renders PAFs stable under harsh chemical treatments. Therefore, PAFs exhibit specificity in their chemistry and functionalities compared with conventional porous materials such as zeolites and metal organic frameworks. The unique features of PAFs render them being tolerant of severe environments and readily functionalized by harsh chemical treatments. The research field of PAFs has experienced rapid expansion over the past decade, and it is necessary to provide a comprehensive guide to the essential development of the field at this stage. Regarding research into PAFs, the synthesis, functionalization, and applications are the three most important topics. In this thematic review, the three topics are comprehensively explained and aptly exemplified to shed light on developments in the field. Current questions and a perspective outlook will be summarized.

Pyrrolidone-based polymers capable of reversible iodine capture for reuse in antibacterial applications

Numerous emerging and re-emerging advanced materials have been successful in capturing iodine pollutants that pose an unprecedented global challenge to public health. However, little attention has been paid to the reutilization of the captured iodine. Herein, we report on a pyrrolidone-based polymer capable of reversible iodine capture for reutilization in antibacterial applications. The pyrrolidone-based polymer poly(N-vinyl-2-pyrrolidone-co-vinyl acetate), denoted as P(VAc-NVP), was synthesized facilely via a one-step radical copolymerization strategy, and the synthesis was regulated by step-by-step optimization, specifically by tuning the feed ratio of NVP to VAc. The as-synthesized P(VAc-NVP) copolymer functioned as an adsorbent for iodine in various solutions, including water/ethanol, cyclohexane, and petroleum ether, in addition to having the special capability of releasing iodine in the presence of starch or bacteria. This opens up a new horizon for its functional practical use as a flexible adsorbent to capture iodine for safe disposal. Interestingly, the P(VAc-NVP) copolymer, after adsorbing iodine, showed antibacterial ability against pathogenic bacteria, including Staphylococcus aureus and Escherichia coli, when a series of simulated and practical antibacterial assays were conducted. It is believed that this proposed strategy based on the synergism of iodine capture and antibacterial use should have great potential for environmental remediation and public healthcare.

Synthesis of conjugated polymers via cyclopentannulation reaction: promising materials for iodine adsorption

A new class of conjugated polymers is prepared by means of a versatile palladium-catalyzed cyclopentannulation reaction using a series of specially designed diethynyl aryl synthons with the commercially available 9,10-dibromoanthracene DBA monomer.

Synthesis of 1,6-disubstituted pyrene-based conjugated microporous polymers for reversible adsorption and fluorescence sensing of iodine

Four 1,6-disubstituted pyrene-based fluorescent conjugated microporous polymers were synthesized by Sonogashira–Hagihara reaction, trimerization reaction of –CN, and Friedel–Crafts reaction, respectively, which can efficient capture and sense I₂.

Exceptionally High CO2 Capture in an Amorphous Polymer with Ultramicropores Studied by Positron Annihilation

A series of amorphous melamine-based polymer networks synthesized by Schiff base chemistry (SNW) were successfully prepared by varying the strut length. The pore structure was analyzed by gas adsorption and positron annihilation methods. Positron lifetime measurements indicate the existence of ultramicropores and also larger mesopores in the SNW materials. The sizes of micropores and mesopores are almost the same in these samples, which are about 0.7 and 16.5 nm, respectively. The relative number of micropores increases in the order of SNW-1 < SNW-2 < SNW-3, while the number of mesopores increases in the reverse order. N₂ adsorption/desorption measurements also reveal micropores and mesopores in these materials. However, it gives an underestimation of the micropore volume. Benefiting from the abundant nitrogen content and high microporosity, the SNW materials exhibit exceptionally high CO₂ capture ability, which reaches a maximum value of 18.3 wt % in SNW-3 at 273 K and 1 bar, followed by SNW-2 and SNW-1. This order is exactly the same as the order of micropore volume revealed by positron annihilation measurement, suggesting that micropores play a crucial role in the CO₂ uptake. Our results show that positron can provide more precise information about the structure of micropores and thus can offer an accurate prediction for the adsorption capacity of complex porous materials.

Polyphenylene Sulfide Ultrafine Fibrous Membrane Modified by Nanoscale ZIF-8 for Highly Effective Adsorption, Interception, and Recycling of Iodine Vapor

In this study, two novel composite membranes containing nanoscale ZIF-8 and polyphenylene sulfide (PPS) nonwoven fabric were prepared via hydrothermal (PPS-ZIF-8) and biomimetic mineralization (PPS-ZIF-8-BSA; BSA, bovine serum albumin) approaches. The biomimetic mineralization approach in particular was extremely rapid and mild, and crystalline ZIF-8 was coated on the PPS substrate in only a few seconds at room temperature. The maximum iodine adsorption capacities of the PPS-ZIF-8 and PPS-ZIF-8-BSA membranes were 2.51 and 2.07 g/g, respectively. The composite fibrous membranes were able to capture trace iodine vapor under differential pressures ranging from 0 to 1000 Pa without almost any iodine vapor leakage. The composite membranes can be applied in harsh environments because of the excellent stability of ZIF-8 and the PPS high-performance fibers. This study provides a promising strategy to fabricate novel adsorption materials for the collection of radioactive iodine during nuclear waste disposal.

Nitrogen-Doped Carbon Materials for the Metal-Free Reduction of Nitro Compounds

In this study, nitrogen-doped carbon materials (labeled as NC-T) were easily prepared by thermal treatment of the melamine-chitosan composite. NC-T catalysts demonstrated good activity toward the reduction of nitro compounds by using hydrazine hydrate (N₂H₄·H₂O) as the reductant. The activity of NC-T enhanced with the rise of the pyrolysis temperature because of the enhanced ratio of graphitic-type nitrogen, which might be the active sites for the reduction of nitro compounds. NC-950 showed high activity for the selective reduction of nitro compounds in hexane to produce amines at yields from 87.5 to 100% at 90 °C using 2 equiv of N₂H₄·H₂O. The NC-950 catalyst demonstrated comparable or even higher catalytic activity in comparison with the reported metal catalysts. The hydrogenation of nitro compounds with N₂H₄·H₂O proceeded via the direct way involving hydroxylamine as the reaction intermediate.