Heterogeneous catalysis is significantly enhanced by the use of highly porous polymers with specific functionalities, such as basic groups, which accelerate reaction rates. Polymers of intrinsic microporosity (PIMs) provide a unique platform for catalytic reactions owing to their high surface areas and customizable pore structures. We herein report a series of Troger's base polymers (TB-PIMs) with enhanced basicity, achieved through the incorporation of nitrogen-containing groups into their repeat units, such as triazine and triphenylamine. These polymers offer a perfect balance between the pore "swellability", which allows the use of substrates of various dimensions, and the basicity of their repeat units, which facilitates the use of reactants with diverse acidity. The catalytic activity is evaluated through the Knoevenagel condensation of benzaldehydes and various methylene species, conducted in the presence of ethanol as a green solvent and using a 1:1 ratio of the two reagents. The results highlight a significant improvement, with reactions reaching completion using just a 1% molar ratio of catalysts and achieving a 3-fold enhancement over previous results with 4-tert-butyl-benzaldehyde. Computational modeling confirms that the enhanced basicity of the repeat units is attributable to the polymer design. Additionally, preliminary studies are undertaken to assess the kinetics of the catalyzed condensation reaction.

This study shows the multistep synthesis of a series of Troger's base polymers of intrinsic microporosity (TB-PIMs) based on a hexaphenylbenzene (HPB) core, with a focus on evaluating their thermal stability, porosity, and CO2 capture performance. Both ladder and linear structures were prepared, designed to feature tunable nitrogen content and porosity. Our findings demonstrate that polymers with higher nitrogen content, such as tetra-TB-HPB, exhibit superior CO2 affinity and selectivity, attributed to enhanced interactions with CO2 and optimized micropore sizes. Linear TB-polymers 1 and 2 are also made for comparison and show competitive performance in carbon capture, suggesting that cost-effective, simpler-to-synthesize materials can achieve efficient gas separation. The study reveals that increased porosity significantly enhances CO2 capacity and selectivity, particularly in networked TB-HPB-PIMs with high surface areas and narrow micropores, achieving values up to 544 m2 g-1, CO2 uptake of 2.00 mmol g-1, and CO2/N2 selectivity of 45.6. The thermal properties of these materials, assessed via thermogravimetric analysis (TGA), show that TB-HPB-PIMs maintain robust thermal stability in nitrogen atmosphere, with tetra- and hexa-TB-HPBs leading the series. However, in oxidative environments, denser polymers such as TB-HPB and linear TB-polymer 1 demonstrate higher performance, likely due to restricted air diffusion. Overall, our findings highlight the critical need to balance porosity and thermal stability in TB-HPB-PIMs for applications in gas separation, carbon capture, and the potential for these polymers as flame retardant materials. Tetra-TB-HPB stands out as the most promising material for CO2 capture and thermal stability under inert conditions, while denser polymers like TB-HPB offer superior performance in oxidative environments.

In this work, a series of hypercrosslinked polymers of intrinsic microporosity (HCP-PIMs), namely nitro-triptycene (TRIP-NO 2 ), amino-triptycene (TRIP-NH 2 ), sulfonated-triptycene (TRIP-SO 3 H) and hydrocarbon-triptycene (TRIP-HC), are employed for the adsorption of organic dyes from wastewater. The materials show the efficient removal of cationic (malachite green, MG) and anionic (methyl orange, MO) dyes. The adsorption parameters herein investigated include the initial pH, the adsorbate concentration and the contact time, with the aim to elucidate their effect on the adsorption process. Furthermore, the adsorption kinetic and isotherms are studied, and the findings suggest the results fit well with pseudo-second-order kinetics and Langmuir model. The reported maximum adsorption capacity is competitive for all the tested polymers. More specifically, TRIP-SO 3 H and TRIP-HC exhibit adsorptions of ~ 303 and ~ 270 mg g −1 for MG and MO, respectively. The selectivity toward cationic and anionic dyes is assessed by mixing the two dyes, and showing that TRIP-HC completely removes both species, whereas TRIP-NO 2 , TRIP-NH 2 and TRIP-SO 3 H show an enhanced selectivity toward the cationic MG, compared to the anionic MO. The effect of the type of water is assessed by performing ultrasonic-assisted adsorption experiments, using TRIP-SO 3 H and TRIP-HC in the presence of either tap or seawater. The presence of competing ions and their concentrations is evaluated by ICP-MS. Our study shows that tap water does not have a detrimental effect on the adsorption of both polymers, whereas, in the presence of seawater, the performance of TRIP-HC toward MO proved to be more stable than MG with TRIP-SO 3 H, which is probably due to a larger concentration of competing ions. Comparison between ultrasonic-assisted and magnetic stirring adsorption demonstrates that the former exhibits a greater efficiency. This seems due to a more rapid mass transfer, driven by the formation of high velocity micro-jets, acoustic microstreaming and shock waves, at the polymer surface. Reusability studies show a good stability up to five adsorption–desorption cycles.

An increasing number of high-performing gas separation membranes is reported almost on a daily basis, yet only a few of them have reached commercialisation while the rest are still considered pure research outcomes. This is often attributable to a rapid change in the performance of these separation systems over a relatively short time. A common approach to address this issue is the development of mixed matrix membranes (MMMs). These hybrid systems typically utilise either crystalline or amorphous additives, so-called fillers, which are incorporated into polymeric membranes at different loadings, with the aim to improve and stabilise the final gas separation performance. After a general introduction to the most relevant models to describe the transport properties in MMMs, this review intends to investigate and discuss the main advantages and disadvantages derived from the inclusion of fillers of different morphologies. Particular emphasis will be given to the study of the compatibility at the interface between the filler and the matrix created by the two different classes of additives, the inorganic and crystalline fillers vs. their organic and amorphous counterparts. It will conclude with a brief summary of the main findings.

Four cationic amidotitanocene complexes [Cp2Ti(NRR ')]-[B(C6F5)4] (Cp = eta 5-C5H5; 1a: R = R ' = p-anisyl; 1b: R = p-fluorophenyl, R ' = p-anisyl; 1c: R = p-fluorophenyl, R ' = phenyl; 1d: R = phenyl, R ' = 2-pyridyl) were synthesized. Complexes 1a-d undergo Ti-N bond homolysis under visible light irradiation. Complexes 1a-c catalyze the polymerization of phenylsilane to yield branched polysilane polymers with molecular weights (Mw) up to approximately 3000 and dispersity indexes (D) of 1.4-1.6. Previously reported Group 4 cationic amidometallocene complexes [Cp2Ti(NPh2)][B(C6F5)4] (Ia) and Cp2Zr(NPh2)][MeB-(C6F5)3] (IIa) were also tested in the hydrosilylation of carbonyl com-pounds with triethylsilane (Et3SiH). In some cases, complex Ia afforded completely reduced products (e.g., ethylbenzene from acetophenone), while IIa was generally more selective (e.g., (1-phenylethoxy)-triethylsilane from acetophenone) but also more active. Complex IIa could also convert anisole derivatives to phenoxysilanes with high efficiency (TON = 2000).

In this paper, we report the design, synthesis, and characterization of a series of hyper-cross-linked polymers of intrinsic microporosity (PIMs), with high CO2 uptake and good CO2/N2 and CO2/CH4 selectivity, which makes them competitive for carbon capture and biogas upgrading. The starting hydrocarbon polymers' backbones were functionalized with groups such as -NO2, -NH2, and -HSO3, with the aim of tuning their adsorption selectivity toward CO2 over nitrogen and methane. This led to a significant improvement in the performance in the potential separation of these gases. All polymers were characterized via Fourier transform infrared (FTIR) spectroscopy and 13C solid-state NMR to confirm their molecular structures and isothermal gas adsorption to assess their porosity, pore size distribution, and selectivity. The insertion of the functional groups resulted in an overall decrease in the porosity of the starting polymers, which was compensated with an improvement in the final CO2 uptake and selectivity over the chosen gases. The best uptakes were achieved with the sulfonated polymers, which reached up to 298 mg g-1 (6.77 mmol g-1), whereas the best CO2/N2 selectivities were recorded by the aminated polymers, which reached 26.5. Regarding CH4, the most interesting selectivities over CO2 were also obtained with the aminated PIMs, with values up to 8.6. The reason for the improvements was ascribed to a synergetic contribution of porosity, choice of the functional group, and optimal isosteric heat of adsorption of the materials.

This study aims to investigate the adsorptive removal of three TCAs; imipramine (IMI), nortriptyline (NOR) and desipramine (DES) using four polymeric networks based on triptycene (TRIP) and triphenylbenzene (TPB). For the first time, these polymeric networks have been used as a pure hydrocarbon (TRIP-HC and TPB-HC) and as their sulfonic acid derivatives (TRIP-SO3H and TPB-SO3H), for the decontamination of TCAs from wastewater. The effect of the initial TCAs concentration was investigated, and it was found that sulfonic acid modified polymers tolerated higher TCAs concentrations than their pure hydrocarbon-based counterparts. Furthermore, the adsorption kinetics and isotherms were studied, which indicated that the four polymers followed pseudosecond-order kinetics and Langmuir isotherm models, respectively. The adsorption capacities values for TRIP-SO3H and TPB-SO3H were between 196.0 and 384.6 mg g(-1), whilst for TRIP-HC and TPB-HC were between 133.3 and 175.4 mg g(-1). The effect of the presence of coexisting ions such as Cl-, NO3- and SO42- was also examined and the adsorption affinities of IMI, NOR and DES were slightly lowered using TRIP-SO3H and TPB-SO3H, on the other hand, a greater decrease was observed using TRIP-HC and TPB-HC. Furthermore, IMI in a tablet formulation was dissolved in tap water and TRIP-SO3H and TPB-SO3H were employed, and it was found they exhibited excellent adsorption efficiencies of 96.96 and 98.78%, respectively. Regeneration of these two polymers was tested by performing five adsorption-desorption cycles and TPB-SO3H showed better stability in comparison to TRIP-SO3H. Finally, a potential mechanistic pathway for the adsorption of theses pharmaceuticals by the polymers was also proposed.

CO2 capture and clean energy production technologies are stirring increasing interest due to the visible effects of global warming on our planet. In the background is a picture of a small lake in Lombardy, Italy, as it appeared in 2018. Novel imide/imine cages have shown promising results in the selective separation of CO2 from N2 and CH4 under vacuum swing adsorption conditions. The cages have also been successfully tested as fillers in mixed-matrix membranes. More information can be found in the Research Article by J. C. Jansen, M. Carta, V. Amendola et al. (DOI: 10.1002/chem.202201631).

Metal and metal-free PIMs have been used in a variety of catalytic reactions, acting as the catalyst itself or aiding in the process. Their characteristic features, such as high porosity, versatile/simple synthesis, thermal/chemical stability and solubility/processability make them attractive and suitable materials for a range of important catalytic processes. Despite this, their use as heterogeneous catalysts has been far less explored than for other porous materials, such as MOFs. In this mini-review we discuss recent developments in the design of PIMs for catalysis in three main reactions: CC bond formation and condensations, CO2 conversion and cyclisations, and oxidations. Furthermore, we outline why we believe PIMs have not yet been fully explored in this field and include an overview of their future prospects.

Two novel imide/imine-based organic cages have been prepared and studied as materials for the selective separation of CO2 from N2 and CH4 under vacuum swing adsorption conditions. Gas adsorption on the new compounds showed selectivity for CO2 over N2 and CH4 . The cages were also tested as fillers in mixed-matrix membranes for gas separation. Dense and robust membranes were obtained by loading the cages in either Matrimid® or PEEK-WC polymers. Improved gas-transport properties and selectivity for CO2 were achieved compared to the neat polymer membranes.

Heterogeneous catalysis plays a pivotal role in the preparation of value-added chemicals, and it works more efficiently when combined with porous materials and supports. Because of that, a detailed assessment of porosity and pore size is essential when evaluating the performance of new heterogeneous catalysts. Herein, we report the synthesis and characterization of a series of novel microporous Tröger’s base polymers and copolymers (TB-PIMs) with tunable pore size. The basicity of TB sites is exploited to catalyze the Knoevenagel condensation of benzaldehydes and malononitrile, and the dimension of the pores can be systematically adjusted with an appropriate selection of monomers and comonomers. The tunability of the pore size provides the enhanced accessibility of the catalytic sites for substrates, which leads to a great improvement in conversions, with the best results achieving completion in only 20 min. In addition, it enables the use of large benzaldehydes, which is prevented when using polymers with very small pores, typical of conventional PIMs. The catalytic reaction is more efficient than the corresponding homogeneous counterpart and is ultimately optimized with the addition of a small amount of a solvent, which facilitates the swelling of the pores and leads to a further improvement in the performance and to a better carbon economy. Molecular dynamic modeling of the copolymers’ structures is employed to describe the swellability of flexible chains, helping the understanding of the improved performance and demonstrating the great potential of these novel materials.

The alcohol and sugar industry in Brazil uses a feedstock for sucrose extraction, resulting in waste production, one of them being the sugarcane bagasse. A possible relocation for the use of this residue, produced in millions of tons annually, would be its use in the production of carbonaceous materials, such as activated carbon (AC). The purpose of this study was the production of activated carbon using a faster, simpler and more efficient process with low energy requirements and chemical reagents to obtain a material with a high surface area. The AC samples were prepared by chemical activation with ZnCl 2 and carbonization at 600 °C in an oxygen-limiting atmosphere. The average specific surface area of the samples, estimated by the BET method, was 1544 m 2 g −1 and the average pore size was 2.6 nm. The surface morphologies of the ACs were characterized using SEM analysis, which showed that the surfaces were irregular, with cracks, pores. The solids were also characterized by FTIR, presenting mainly stretching bands corresponding to O–H, C–O, and C=C groups. EPR analysis showed a resonance line characteristic of an organic free radical with g ~ 2.0031, which is typical of free radicals centered on carbon atoms. The material efficiency for removal of aromatic organic pollutants was evaluated in continuous-flow adsorption tests with the antibiotic amoxicillin. The method provided very satisfactory results, reducing the concentration of the antibiotic from an initial value of 1.37 × 10 −3 mol L −1 to about 3.5 × 10 −8 mol L −1 . The concentration of the antibiotic in water, after adsorption, was therefore reduced by four to five orders of magnitude, confirming the potential application of the materials prepared in this work for the removal of antibiotics residues from the environment.

New microporous polymer networks, constructed by a nucleophilic substitution reaction between two different porphyrins and metalloporphyrins are reported. The meso-tetrakis-(pentafluorophenyl)por phyrin HP1 (monomer A1) and/or its manganese complex MP1 (monomer A2) was reacted with the meso-tetrakis-(3,4-dihydroxyphenyl)porphyrin HP2 (monomer B1) and/or its manganese complex MP2 (monomer B2), giving rise to four new porphyrin-based microporous network polymers (P1-P4) with apparent BET surface areas in the range 600-1200 m(2) g(-1). The catalytic performance of the polymers was evaluated by oxidation reactions using cyclooctene and cyclohexane as substrates and lodosylbenzene as oxidant in cytochrome P-450 model reactions. The catalytic activity and selectivity of these porous polymer networks are similar or superior to those of the analogous homogeneous manganese porphyrins MP1 and MP2. The robustness of the materials in terms of thermal stability and good recyclability showed that they hold great promise as biomimetic heterogeneous catalysts. (C) 2018 Elsevier Inc. All rights reserved.

Synthetic metalloporphyrins (MP) have been widely investigated as catalysts in oxidation reactions, mainly regarding the mimicking of cytochrome P-450 enzymes, both in homogeneous and heterogeneous catalysis studies, showing promising results. Heterogeneous catalysis has advantages over the homogeneous one, like the possibility of the catalyst reuse in other catalytic cycles. In the present work, is reported the preparation of polymeric structures through reaction between the free base porphyrin (P) or the metalloporphyrin (MP) and the diisocyanate 4,4' diphenyl methane (MDI), that was performed in a similar reaction to those used for synthesis of polyurethanes (PU), obtaining insoluble solids in common organic solvents (SP and SMPx). The presence of metalloporphyrins in the solids was confirmed by UV-Vis and infrared vibrational spectroscopy. The solid SMP1 showed catalytic activity similar to the metalloporphyrin MP in solution (homogeneous catalysis) in cis-cyclooctene oxidation, being easily recovered and reused in another catalytic cycle.

The highly efficient dibenzodioxin-forming reaction between the (pentafluorophenyl)porphyrin manganese(III) (MnP) and hexahydroxytriptycene (HHT) provide a new microporous network polymer (P1), which demonstrated a large surface area (1080 m2 g− 1) and proved to be an efficient solid for heterogeneous catalysis for cyclooctene and cyclohexane oxidation under mild conditions and with high capacity of recovery and reuse in many catalytic cycles.

Unsymmetric porphyrins containing both pentafluorophenyl (PFP = A) and 3,4-dimethoxyphenyl (DMP = B) substituents at the meso positions were prepared using Lindsey's methodology.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Nitrate-intercalated Mg-Al layered double hydroxides (LDHs) were synthesized and exfoliated in formamide. Reaction of the single layer suspension with thiosalicylic acid under different conditions afforded two types of solids: LDHA1, in which the outer surface was modified with the anion thiosalicylate, and LDHA2, which contained the anion thiosalicylate intercalated between the LDH layers. LDHA1 and LDHA2 were used as supports to immobilize neutral (FeP1 and FeP2) and anionic (FeP3) iron(III) porphyrins. For comparison purposes, the iron(III) porphyrins (FePs) were also immobilized on LDH intercalated with nitrate anions obtained by the co-precipitation method. Chemical modification of LDH facilitated immobilization of the FePs through interaction of the functionalizing groups in LDH with the peripheral substituents on the porphyrin ring. The resulting FePx-LDHAy solids were characterized by X-ray diffraction (powder) and UV-Vis and EPR spectroscopies and were investigated as catalysts in the oxidation of cyclooctene and cyclohexane. The immobilized neutral FePs and their homogeneous counterparts gave similar product yields in the oxidation of cyclooctene, suggesting that immobilization of the FePs on the thiosalicylate-modified LDHs only supported the catalyst species without interfering in the catalytic outcome. On the other hand, in the oxidation of cyclohexane, the thiosalicylate anions on the outer surface of LDHA1 or intercalated between the LDHA2 layers influenced the catalytic activity of FePx-LDHAy, leading to different efficiency and selectivity results. FeP1-LDHA2 performed the best (29.6% alcohol yield) due to changes in the polarity of the surface of the support and the presence of FeP1. Interestingly, FeP1 also performed better in solution as compared to the other FePs. Finally, it was possible to recycle FeP1-LDHA2 at least three times. (C) 2016 Elsevier Inc. All rights reserved.