Aluminum Porphyrin-Based Ionic Porous Aromatic Frameworks Having High Surface Areas and Highly Dispersed Dual-Function Sites for Boosting the Catalytic Conversion of CO2 into Cyclic Carbonates

Ionic porous materials: from synthetic strategies to applications in gas separation and catalysis

Ionic porous materials possess a unique combination of tunable pore sizes and task-specific interactions between guest molecules and the charged frameworks, which endow them with versatility across diverse domains in chemistry and materials science. Significant advancements in their applications for gas separation and catalysis have been achieved in recent years due to the incorporation of ionic functionalities and ultra-microporous structures that enable molecular-scale recognition of guest molecules. This review summarizes recent advancements in the synthetic strategies of ionic porous materials, establishing design guidelines for the incorporation of ionic moieties into the backbone to fine-tune pore sizes and chemistry. It highlights the synergistic interplay of task-specific interactions with custom-designed pore structures in key applications, including adsorption separation, membrane separation, and gas conversion. Additionally, it examines structure-property relationships, offering deeper insights into enhancing performance. The report also addresses the current challenges in the practical application of these materials. Finally, the review provides future perspectives on ionic porous materials from both scientific and industrial viewpoints. Overall, this review aims to provide insights into pore structure and chemistry, supporting the precise placement of ionic functionalities.

Advanced Porous Aromatic Frameworks: A Comprehensive Overview of Emerging Functional Strategies and Potential Applications

Porous aromatic frameworks (PAFs) are a fundamental group of porous materials characterized by their distinct structural features and large surface areas. These materials are synthesized from aromatic building units linked by strong carbon-carbon bonds, which confer exceptional rigidity and long-term stability. PAFs functionalities may arise directly from the intrinsic chemistry of their building units or through the postmodification of aromatic motifs using well-defined chemical processes. Compared to other traditional porous materials such as zeolites and metallic-organic frameworks, PAFs demonstrate superior stability under severe chemical treatments due to their robust carbon-carbon bonding. Even in challenging environments, the chemical stability and ease of functionalization of PAFs demonstrate their flexibility and specificity. Research on PAFs has significantly expanded and accelerated over the past decade, necessitating a comprehensive overview of key advancements in this field. This review provides an in-depth analysis of the recent advances in the synthesis, functionalization, and dimensionality of PAFs, along with their distinctive properties and wide-ranging applications. This review explores the innovative methodologies in PAFs synthesis, the strategies for functionalizing their structures, and the manipulation of their dimensionality to tailor their properties for specific potential applications. Similarly, the key application areas, including batteries, absorption, sensors, CO2 capture, photo-/electrocatalytic usages, supercapacitors, separation, and biomedical are discussed in detail, highlighting the versatility and potential of PAFs in addressing modern scientific and industrial challenges.

Boosting CO2 Catalytic Fixation to Cyclic Carbonates over Aluminum Porphyrin-Based Porous Hyper-Cross-Linked Ionic Polymers via Synthetic Control of Active Site Proximity

Multifunctionalization of porous organic polymers (POPs) toward cooperative CO2 catalysis has attracted so much attention in recent years, but it still remains a huge challenge to scientists. In this contribution, a concise and efficient method to construct aluminum porphyrin-based hyper-cross-linked ionic polymers has been demonstrated for the first time, which are featured with high surface areas and hierarchical structures. Obviously, the preparation of metalloporphyrin-based hyper-cross-linked polymers with tetraphenylmethane-derived three-dimensional structures is beneficial for the introduction of abundant ionic active sites and the formation of hierarchical porous structures. By regulating the locations and amounts of cooperative active sites to make them highly dispersed and easily accessible, the catalytic activity of as-maded catalyst can be greatly improved for CO2 cycloaddition conversion to cyclic carbonates without cocatalysts and solvents, providing the highest initial turnover frequency up to 8400 h-1 of heterogeneous catalysts reported to date. In addition, the catalyst can be easily recovered by filtration and reused at least ten times without a significant decrease in catalytic activity. This work not only presents a promising strategy to improve the catalytic activity by controlling active site proximity via different synthetic methods but also offers an attractive perspective in the field of CO2 catalytic conversion.

Task-Specific Design of a Porous Aromatic Framework as an Ultrastable Platform for Enantioselective Organocatalysis

A hydroxyl-tagged porous aromatic framework PAF-NBU2-OH was task-specifically designed and successfully synthesized targeted toward immobilizing chiral catalysts. Using proline-type compound as model chiral organocatalyst, PAF-NBU2-OH was used as a platform to covalently link proline-type group. The obtained PAF-immobilized organocatalyst PAF-NBU2-OPro featured high chemical stability in different solvents even under very harsh conditions. PAF-NBU2-OPro showed excellent catalytic activity, diastereoselectivity and enantioselectivity with complete and easy recyclability when catalyzing the aldol reaction between p-nitrobenzaldehyde and cyclohexanone, which could undergo at least 30 cycles without any activity, diastereoselectivity or enantioselectivity loss for catalyzing the current reaction.

Bifunctional chlorhexidine-based covalent organic polymers for CO2 capture and conversion without a co-catalyst

Two new cobalt/zinc-coordinated bifunctional covalent organic polymers (COP-Co and COP-Zn) based on chlorhexidine are prepared as heterogeneous catalysts for carbon dioxide (CO2) conversion. Due to the Cl- nucleophile and cobalt/zinc Lewis acid sites, COP-Co and COP-Zn can efficiently convert CO2 and epoxides into cyclic carbonates under mild conditions without a co-catalyst.

Conjugated Microporous Polymers for Catalytic CO2 Conversion

Rising carbon dioxide (CO2) levels in the atmosphere are recognized as a threat to atmospheric stability and life. Although this greenhouse gas is being produced on a large scale, there are solutions to reduction and indeed utilization of the gas. Many of these solutions involve costly or unstable technologies, such as air-sensitive metal-organic frameworks (MOFs) for CO2 capture or "non-green" systems such as amine scrubbing. Conjugated microporous polymers (CMPs) represent a simpler, cheaper, and greener solution to CO2 capture and utilization. They are often easy to synthesize at scale (a one pot reaction in many cases), chemically and thermally stable (especially in comparison with their MOF and covalent organic framework (COF) counterparts, owing to their amorphous nature), and, as a result, cheap to manufacture. Furthermore, their large surface areas, tunable porous frameworks and chemical structures mean they are reported as highly efficient CO2 capture motifs. In addition, they provide a dual pathway to utilize captured CO2 via chemical conversion or electrochemical reduction into industrially valuable products. Recent studies show that all these attractive properties can be realized in metal-free CMPs, presenting a truly green option. The promising results in these two fields of CMP applications are reviewed and explored here.

Cobalt porphyrin-based hypercrosslinked ionic polymers as biomimetic nanoreactors for CO2 conversion to cyclic carbonates

A simple and low-cost approach to construct one type of cobalt porphyrin-based hypercrosslinked ionic polymer with high specific surface areas, densely located ionic groups and highly dispersed cobalt sites has been demonstrated, which act as bifunctional catalysts for the solvent-additive-free conversion of CO2 into cyclic carbonates with outstanding biomimetic catalytic performance and good recyclability.

Two in one: aluminum porphyrin-based porous organic polymers containing symmetrical quaternary phosphonium salts for catalytic conversion of CO2 into cyclic carbonates

Based on the double activation models of epoxides, the design and synthesis of ionic porous organic polymers (iPOPs) is considered to be very attractive and promising but has remained a great challenge in recent decades owing to electrostatic interactions between charged groups. In this contribution, we developed a two-in-one strategy to fabricate metalloporphyrin-based iPOPs with unique nanostructures (named AlPor-QP@POP), which are composed of aluminum porphyrin units and three-dimensional quaternary phosphonium salts that work synergistically in the cycloaddition of CO2 with epoxides under mild conditions. The high symmetry of two monomers allows them to possess similar reactivity ratios and thus endows AlPor-QP@POP with densely located active sites, a large surface area and good CO2 capture capacity. More importantly, bifunctional AlPor-QP@POP has enormous potential to produce cyclic carbonates with simulated flue gas under ambient conditions. Moreover, AlPor-QP@POP can be readily recycled and efficiently reused more than ten times without an obvious decrease in catalytic activity. Finally, kinetic investigations and a comparative study have been conducted to understand the possible mechanism of CO2 catalytic cycloaddition.

Fe(III)-incorporated porphyrin-based conjugated organic polymer as a peroxidase mimic for the sensitive determination of glucose and H2O2

Nanozymes, i.e., nanomaterials that possess intrinsic enzyme-like behaviour, have thrived over the past few decades owing to their advantages of superior stability and effortless storage. Such artificial enzymes can be a perfect alternative to naturally occurring enzymes, which have disadvantages of high cost and limited functionality. In this work, we present the fabrication of an Fe(III)-incorporated porphyrin-based conjugated organic polymer as a nanozyme for the efficient detection of glucose through its intrinsic peroxidase activity and the amperometric detection of hydrogen peroxide. The iron-incorporated porphyrin-based conjugated organic polymer (Fe-DMP-POR) possesses a spherical morphology with high chemical and thermal stability. Exploiting the peroxidase-mimicking activity of the material for the determination of glucose, a detection limit of 4.84 μM is achieved with a linear range of 0-0.15 mM. The Fe-DMP-POR also exhibits a reasonable recovery range for the detection of human blood glucose. The as-synthesized material can also act as an H2O2 sensor, with a sensitivity of 947.67 μA cm-2 mM-1 and a limit of detection of 3.16 μM.