Photothermal conversion triggered thermal asymmetric catalysis within metal nanoparticles loaded homochiral covalent organic framework

Covalent organic framework with donor-acceptor structure for rapid and sensitive photothermal sensing detection

Given the serious harm caused by dietary intake of diethylstilbestrol (DES), it is urgent to explore rapid and sensitive DES sensing methods. In this work, a photothermal DES immunochromatography sensor based on covalent organic framework (COF) was constructed. The performance of COF in the field of photothermal sensing was systematically investigated for the first time. A donor-acceptor type of COF with a photothermal conversion rate of 51.17 % was synthesized. The logarithm of the DES concentrations-temperature change value standard curve was plotted. The intensity of the photothermal sensing signal was inversely proportional to the sample concentration. The detection limit of the proposed photothermal method (0.24 μg·L-1) was 10 times higher than that of visual detection (3 μg·L-1). This work not only constructed a novel detection method for DES sensing, but also provided a feasible demonstration for the application of COF in photothermal sensing and expanded the application of their photothermal properties.

Metalated covalent organic frameworks as efficient catalysts for multicomponent tandem reactions

Multicomponent tandem reactions have become indispensable synthetic methods due to their economic advantages and efficient usage in natural products and drug synthesis. The emergence of metalated covalent organic frameworks (MCOFs) has opened up new opportunities for the advancement of multicomponent tandem reactions. In contrast to commonly used homogeneous transition metal catalysts, MCOFs possess regular porosity, high crystallinity, and rich metal chelation sites that facilitate the uniform distribution and anchoring of metals within their cavities. Thus, they show extremely high activity and have recently been widely employed as catalysts for multicomponent tandem reactions. It is timely to conduct a review of MCOFs in multicomponent tandem reactions, in order to offer guidance and assistance for the synthesis of MCOF catalysts and their application in multicomponent tandem reactions. This review provides a comprehensive overview of the design and synthesis of MCOFs, their application and progress in multicomponent tandem reactions, and the primary challenges encountered during their current development with the aim of contributing to the promotion of the field.

Biomimetic Chiral Nanomaterials with Selective Catalysis Activity

Chiral nanomaterials with unique chiral configurations and biocompatible ligands have been booming over the past decade for their interesting chiroptical effect, unique catalytical activity, and related bioapplications. The catalytic activity and selectivity of chiral nanomaterials have emerged as important topics, that can be potentially controlled and optimized by the rational biochemical design of nanomaterials. In this review, chiral nanomaterials synthesis, composition, and catalytic performances of different biohybrid chiral nanomaterials are discussed. The construction of chiral nanomaterials with multiscale chiral geometries along with the underlying principles for enhancing chiroptical responses are highlighted. Various biochemical approaches to regulate the selectivity and catalytic activity of chiral nanomaterials for biocatalysis are also summarized. Furthermore, attention is paid to specific chiral ligands, materials compositions, structure characteristics, and so on for introducing selective catalytic activities of representative chiral nanomaterials, with emphasis on substrates including small molecules, biological macromolecule, and in-site catalysis in living systems. Promising progress has also been emphasized in chiral nanomaterials featuring structural versatility and improved chiral responses that gave rise to unprecedented chances to utilize light for biocatalytic applications. In summary, the challenges, future trends, and prospects associated with chiral nanomaterials for catalysis are comprehensively proposed.

Accessible Tetrathiafulvalene Moieties in a 3D Covalent Organic Framework for Enhanced Near-Infrared Photo-Thermal Conversion and Photo-Electrical Response

Redox-active tetrathiafulvalene (TTF)-based covalent organic frameworks (COFs) exhibit distinctive electrochemical and photoelectrical properties, but their prevalent two-dimensional (2D) structure with densely packed TTF moieties limits the accessibility of redox center and constrains their potential applications. To overcome this challenge, an 8-connected TTF linker (TTF-8CHO) is designed as a new building block for the construction of three-dimensional (3D) COFs. This approach led to the successful synthesis of a 3D COF with the bcu topology, designated as TTF-8CHO-COF. In comparison to its 2D counterpart employing a 4-connected TTF linker, the 3D COF design enhances access to redox sites, facilitating controlled oxidation by I2 or Au3+ to tune physical properties. When irradiated with a 0.7 W cm-2 808 nm laser, the oxidized 3D COF samples (I X - ${\mathrm{I}}_{\mathrm{X}}^{-}$ @TTF-8CHO-COF and Au NPs@TTF-8CHO-COF) demonstrated rapid temperature increases of 239.3 and 146.1 °C, respectively, which surpassed those of pristine 3D COF (65.6 °C) and the 2D COF counterpart (6.4 °C increment after I2 treatment). Furthermore, the oxidation of the 3D COF heightened its photoelectrical responsiveness under 808 nm laser irradiation. This augmentation in photothermal and photoelectrical response can be attributed to the higher concentration of TTF·+ radicals generated through the oxidation of well-exposed TTF moieties.

Construction of Multifunctional Covalent Organic Frameworks for Photocatalysis

Covalent organic frameworks (COFs) have recently drawn intense attention due to their potential applications in photocatalysis. Herein, we report a multifunctional COF which consists of triphenylamine (TPA) and 2,2'-bipyridine (2, 2'-bipy) entities. The obtained TAPA-BPy-COF is a heterogeneous photocatalyst and can efficiently catalyze the oxidative coupling of thiols to disulfides. In addition, TAPA-BPy-COF can be further metalated by Pd(II) via 2,2'-bipy-metal coordination. The generated Pd@TAPA-BPy-COF can highly promote photocatalytic synthesis of 3-cyanopyridines via cascade addition/cyclization of arylboronic acids with γ-ketodinitriles in heterogeneous way. This work has demonstrated the way for the rational design and preparation of more efficient photoactive COFs for photocatalysis.

Drug delivery using biocompatible covalent organic frameworks (COFs) towards a therapeutic approach

Covalent organic frameworks (COFs) are constructed exclusively with lightweight organic scaffolds, which can have a 2D or 3D architecture. The ease of synthesis, robust skeleton and tunable properties of COFs make them superior candidates among their counterparts for a wide range of uses including biomedical applications. In the biomedical field, drug delivery or photodynamic-photothermal (PDT-PTT) therapy can be individually considered a potential parameter to be investigated. Therefore, this comprehensive review is focused on drug delivery using COFs, highlighting the encapsulation and decapsulation of drugs by COF scaffolds and their delivery in biological media including live cells. Versatile COF scaffolds together with the delivery of several drug molecules are considered. We attempted to incorporate the status of drug encapsulation and decapsulation considering a wide range of recent publications.

Turning on Asymmetric Catalysis of Achiral Metal-Organic Frameworks by Imparting Chiral Microenvironment

The development of heterogeneous asymmetric catalysts has attracted increasing interest in synthetic chemistry but mostly relies on the immobilization of homogeneous chiral catalysts. Herein, a series of chiral metal-organic frameworks (MOFs) have been fabricated by anchoring similar chiral hydroxylated molecules (catalytically inactive) with different lengths onto Zr-oxo clusters in achiral PCN-222(Cu). The resulting chiral MOFs exhibit regulated enantioselectivity up to 83 % ee in the asymmetric ring-opening of cyclohexene oxide. The chiral molecules furnished onto the catalytic Lewis sites in the MOF create multilevel microenvironment, including the hydrogen interaction between the substrate and the chiral -OH group, the steric hindrance endowed by the benzene ring on the chiral molecules, and the proximity between the catalytic sites and chiral molecules confined in the MOF pores, which play crucial roles and synergistically promote chiral catalysis. This work nicely achieves heterogeneous enantioselective catalysis by chiral microenvironment modulation around Lewis acid sites.

Promises of Plasmonic Antenna-Reactor Systems in Gas-Phase CO2 Photocatalysis

Sunlight-driven photocatalytic CO2 reduction provides intriguing opportunities for addressing the energy and environmental crises faced by humans. The rational combination of plasmonic antennas and active transition metal-based catalysts, known as "antenna-reactor" (AR) nanostructures, allows the simultaneous optimization of optical and catalytic performances of photocatalysts, and thus holds great promise for CO2 photocatalysis. Such design combines the favorable absorption, radiative, and photochemical properties of the plasmonic components with the great catalytic potentials and conductivities of the reactor components. In this review, recent developments of photocatalysts based on plasmonic AR systems for various gas-phase CO2 reduction reactions with emphasis on the electronic structure of plasmonic and catalytic metals, plasmon-driven catalytic pathways, and the role of AR complex in photocatalytic processes are summarized. Perspectives in terms of challenges and future research in this area are also highlighted.

Super-Photothermal Effect-Mediated Fast Reaction Kinetic in S-Scheme Organic/Inorganic Heterojunction Hollow Spheres Toward Optimized Photocatalytic Performance

Using full solar spectrum for energy conversion and environmental remediation is a major challenge, and solar-driven photothermal chemistry is a promising route to achieve this goal. Herein, this work reports a photothermal nano-constrained reactor based on hollow structured g-C₃ N₄ @ZnIn₂ S₄ core-shell S-scheme heterojunction, where the synergistic effect of super-photothermal effect and S-scheme heterostructure significantly improve the photocatalytic performance of g-C₃ N₄ . The formation mechanism of g-C₃ N₄ @ZnIn₂ S₄ is predicted in advance by theoretical calculations and advanced techniques, and the super-photothermal effect of g-C₃ N₄ @ZnIn₂ S₄ and its contribution to the near-field chemical reaction is confirmed by numerical simulations and infrared thermography. Consequently, the photocatalytic degradation rate of g-C₃ N₄ @ZnIn₂ S₄ for tetracycline hydrochloride is 99.3%, and the photocatalytic hydrogen production is up to 4075.65 µmol h^-1 g^-1 , which are 6.94 and 30.87 times those of pure g-C₃ N₄ , respectively. The combination of S-scheme heterojunction and thermal synergism provides a promising insight for the design of an efficient photocatalytic reaction platform.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Macrocycle-Based Covalent Organic Frameworks

Macrocycles with well-defined cavities and the ability to undergo supramolecular interactions are classical materials that have played an essential role in materials science. However, one of the most substantial barriers limiting the utilization of macrocycles is their aggregation, which blocks the active regions. Among many attempted strategies to prevent such aggregation, installing macrocycles into covalent organic frameworks (COFs), which are porous and stable reticular networks, has emerged as an ideal solution. The resulting macrocycle-based COFs (M-COFs) preserve the macrocycles' unique activities, enabling applications in various fields such as single-atom catalysis, adsorption/separation, optoelectronics, phototherapy, and structural design of forming single-layered or mechanically interlocked COFs. The resulting properties are unmatchable by any combination of macrocycles with other substrates, opening a new chapter in advanced materials. This review focuses on the latest progress in the concepts, synthesis, properties, and applications of M-COFs, and presents an in-depth outlook on the challenges and opportunities in this emerging field.

Calcium-peroxide-mediated cascades of oxygen production and glutathione consumption induced efficient photodynamic and photothermal synergistic therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) are potent approaches to cancer treatment. However, the tumor microenvironment (TME) characterized by severe hypoxia and abundant glutathione (GSH) significantly reduces the effectiveness of PDT. In this study, we developed an oxidative stress amplifier CaO₂/ICG@ZIF-8, which was capable of self-sufficient O₂ delivery and GSH depletion to enhance PDT and PTT synergistic therapy. We utilized ZIF-8 as nanocarriers that when loaded with CaO₂ and indocyanine green (ICG) form CaO₂/ICG@ZIF-8 nanoparticles, which exhibit a uniform particle size distribution and a hydrated particle size of about 215 nm. CaO₂ reacts with water under acidic conditions to produce O₂ so CaO₂/ICG@ZIF-8 has an excellent O₂ supply capacity, which is essential for PDT. Moreover, CaO₂/ICG@ZIF-8 also reacts with GSH to form glutathione disulfides (GSSH), enhancing the therapeutic outcome of PDT by preventing the consumption of local ractive oxygen species. Beyond that, CaO₂/ICG@ZIF-8 can produce strong hyperthermia with a photothermal conversion efficiency of about 44%, which is exceedingly appropriate for PTT. Owing to its augmentation, PTT/PDT mediated by CaO₂/ICG@ZIF-8 demonstrates intense tumor inhibitory effects in both in vitro and in vivo studies. Notably, the Zn and Ca generated by CaO₂/ICG@ZIF-8 degradation are essential elements for the body, so CaO₂/ICG@ZIF-8 shows favorable safety. Altogether, the research provides a promising PDT/PTT synergistic therapeutic strategy for cancer and may show more medical applications in the future.

Chiral Frustrated Lewis Pair@Metal-Organic Framework as a New Platform for Heterogeneous Asymmetric Hydrogenation

Asymmetric hydrogenation, a seminal strategy for the synthesis of chiral molecules, remains largely unmet in terms of activation by non-metal sites of heterogeneous catalysts. Herein, as demonstrated by combined computational and experimental studies, we present a general strategy for integrating rationally designed molecular chiral frustrated Lewis pair (CFLP) with porous metal-organic framework (MOF) to construct the catalyst CFLP@MOF that can efficiently promote the asymmetric hydrogenation in a heterogeneous manner, which for the first time extends the concept of chiral frustrated Lewis pair from homogeneous system to heterogeneous catalysis. Significantly, the developed CFLP@MOF, inherits the merits of both homogeneous and heterogeneous catalysts, with high activity/enantio-selectivity and excellent recyclability/regenerability. Our work not only advances CFLP@MOF as a new platform for heterogeneous asymmetric hydrogenation, but also opens a new avenue for the design and preparation of advanced catalysts for asymmetric catalysis.

Reticular Synthesis of One-Dimensional Covalent Organic Frameworks with 4-c sql Topology for Enhanced Fluorescence Emission

Covalent organic frameworks (COFs) have been extensively investigated due to their unique structure, porosity, and functionality. However, at the topological level, COFs remain as two-dimensional (2D) or three-dimensional (3D) structures, while COFs with one-dimensional (1D) topology have not been systematically explored. In this work, we proposed a synthetic strategy for the construction of 1D-COFs based on non-linear edges and suitable high-symmetry vertices. Compared with their 2D-COFs counterparts, the 1D-COFs with AIEgens located at the vertex of the frame exhibited enhanced fluorescence. The density functional theory (DFT) calculations revealed that the dimensional-induced rotation restriction (DIRR) effect could spontaneously introduce additional non-covalent interactions between the strip frames, which could substantially diminish non-radiative transitions. This work also provides protocols for the design of 1D-COFs and a guidance scheme for the synthesis of emitting COFs.

Porphyrin-based conjugated organic polymer with dual metal sites for highly active and selective visible-light-driven reduction of CO2 to CO

A porphyrin-based conjugated organic polymer (COP) was constructed from 5,10,15,20-tetrakis(4-bromophenyl)porphyrin copper (CuTBPP) and 5,5'-bis-ethynyl-2,2'-bipyridine (BPY) via Sonogashira coupling. Its complex Co/CuTBPP-BPY-COP (with dual metal sites composed of copper porphyrin and a cobalt BPY unit) was prepared by coordination with Co²⁺. All of the prepared CuTBPP-BPY-COP and Co/CuTBPP-BPY-COP compounds exhibited excellent photocatalytic performance toward CO₂ reduction under visible-light irradiation without another sacrificial reagent but only H₂O. Co/CuTBPP-BPY-COP (dual metal sites) exhibited better photocatalytic activity than CuTBPP-BPY-COP (a single metal site). Co/CuTBPP-BPY-COP retained a higher photocatalysis capacity for CO₂ reduction after 10 consecutive cycles. The total quantity of CO product was 263.2 μmol g^-1 after 10 h of irradiation. Theoretical studies indicate that introducing Co metal centers and nitro groups are more favorable for the photoreduction catalysis of CO₂ compared with that using CuTBPP-BPY-COP.

Zero Energy Heating of Solvent with Network-Structured Solar-Thermal Material: Eco-Friendly Palladium Catalysis of the Suzuki Reaction

Solar-thermal materials absorb sunlight and convert it into heat, which is released into the surrounding medium. Utilization of solar energy for solvent heating can be a potential method of eco-friendly organic reactions. However, to date, significant heating of the entire volume of a solvent by 1 sun illumination has not been reported. In the present work, a network structure of solar-thermal materials has been proposed for zero energy heating of a solvent under 1 sun illumination. A network-structured solar-thermal material with an additional catalytic function was fabricated by sputtering palladium into a melamine sponge. The nanocrystalline palladium-decorated melamine sponge (Pd-sponge) has excellent sunlight absorption properties in the entire wavelength range that enable efficient solar-thermal conversion. The Pd-sponge can reduce heat loss to the surroundings by effectively blocking thermal radiation from the heated solvent. The temperature of the reaction solution with the ethanol-water mixture filled in the Pd-sponge increased from 23 to 59 °C under 1 sun illumination. The elevated temperature of the reaction solutions by solar-thermal conversion successfully accelerated the heterogeneous Pd-catalyzed Suzuki coupling reactions with high conversions. Easy and low-energy-consuming multicycle use of the solar-thermal and catalytic properties of the Pd-sponge has also been demonstrated.

Challenges and opportunities for chiral covalent organic frameworks

As highly versatile crystalline porous materials, covalent organic frameworks (COFs) have emerged as an ideal platform for developing novel functional materials, attributed to their precise tunability of structure and functionality. Introducing chiral functional units into frameworks produces chiral COFs (CCOFs) with chiral superiorities through chirality conservation and conversion processes. This review summarises recent research progress in CCOFs, including synthetic methods, chiroptical characterisations, and their applications in asymmetric catalysis, chiral separation, and enantioselective recognition and sensing. Challenges and limitations are discussed to uncover future opportunities in CCOF research.

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

Covalent organic frameworks (COFs) are a class of organic crystalline porous materials discovered in the early 21st century that have become an attractive class of emerging materials due to their high crystallinity, intrinsic porosity, structural regularity, diverse functionality, design flexibility, and outstanding stability. However, many chemical and physical properties strongly depend on the presence of metal ions in materials for advanced applications, but metal-free COFs do not have these properties and are therefore excluded from such applications. Metalated COFs formed by combining COFs with metal ions, while retaining the advantages of COFs, have additional intriguing properties and applications, and have attracted considerable attention over the past decade. This review presents all aspects of metalated COFs, from synthetic strategies to various applications, in the hope of promoting the continued development of this young field.

Thermoplasmonics in Solar Energy Conversion: Materials, Nanostructured Designs, and Applications

The indispensable requirement for sustainable development of human society has forced almost all countries to seek highly efficient and cost-effective ways to harvest and convert solar energy. Though continuous progress has advanced, it remains a daunting challenge to achieve full-spectrum solar absorption and maximize the conversion efficiency of sunlight. Recently, thermoplasmonics has emerged as a promising solution, which involves several beneficial effects including enhanced light absorption and scattering, generation and relaxation of hot carriers, as well as localized/collective heating, offering tremendous opportunities for optimized energy conversion. Besides, all these functionalities can be tailored via elaborated designs of materials and nanostructures. Here, first the fundamental physics governing thermoplasmonics is presented and then the strategies for both material selection and nanostructured designs toward more efficient energy conversion are summarized. Based on this, recent progress in thermoplasmonic applications including solar evaporation, photothermal chemistry, and thermophotovoltaic is reviewed. Finally, the corresponding challenges and prospects are discussed.

A facile imine-linked covalent organic framework doped with a carbon dot composite for the detection and removal of Hg2+ in surface water

Hg2+ is one of the most toxic chemical species in the water environment, and thus developing a new fluorescent covalent organic framework for both the detection and removal of Hg2+ is highly desirable. Herein, a fluorescent composite, termed TpPa-1 COF@CDs, was synthesized by inverse emulsion polymerization method using an imine covalent organic framework as the supporting material and carbon dots as the fluorescent sensor element. The crystallinity, porosity, rich functional receptors (hydroxyl and amino groups), thermal stability and fluorescent properties of TpPa-1 COF@CDs were characterized. The results showed that TpPa-1 COF@CDs exhibited a good detection and removal performance for Hg2+, which was evidenced by its high sensitivity (LOD = 0.75 μg L-1), superior selectivity, large adsorption capacity (235 mg g-1), fast adsorption rate (30 min equilibrium time) and good regeneration (at least five cycles). More importantly, the simple functional monomer, short reaction time and metal-free raw material made TpPa-1 COF@CDs reliable, cost effective and eco-friendly. This research demonstrated the facile construction of a functional covalent organic framework composite for water environmental remediation technologies of metal pollution.

Synthesis of Chiral Covalent Organic Frameworks via Asymmetric Organocatalysis for Heterogeneous Asymmetric Catalysis

A general and efficient organocatalytic asymmetric polymerization approach for the synthesis of chiral covalent organic frameworks (CCOFs) has been developed. With a chiral 2-methylpyrrolidine catalyst, a series of tris(N-salicylideneamine)-derived β-ketoenamine-CCOFs are directly constructed from prochiral aldehyde- and primary amine-monomers. The adopted aminocatalytic asymmetric Schiff-base condensation herein is performed under ambient conditions with clear green synthetic advantages over the conventional acid-catalysed solvothermal methods. The obtained β-ketoenamine-CCOFs can be further metalated by a solid-state coordination approach, and the resulting Cu^II @CCOFs can highly promote an asymmetric A³ -coupling reaction. Specifically, a Cu^II @CCOF@chitosan aerogel was fabricated as a highly efficient fixed-bed model reactor for scaled-up catalysis. The concept of aminocatalytic asymmetric polymerization might open a new way for constructing the CCOFs via asymmetric organocatalysis.

Synthesis of Metal-Free Chiral Covalent Organic Framework for Visible-Light-Mediated Enantioselective Photooxidation in Water

Although chiral covalent organic frameworks (CCOFs) presence grows in thermal asymmetric catalysis, their application in equally important asymmetric photocatalysis has yet to begin. Herein, we first report a propargylamine-linked and quaternary ammonium bromide decorated porphyrin-CCOF which can highly promote visible-light-driven enantioselective photooxidation of sulfides to sulfoxides in water and in air. This methodology has also been applied to the synthesis of (R)-modafinil, a wakefulness-promoting medication used for the treatment of excessive sleepiness. This research might open a new way for the application of CCOFs in asymmetric photocatalysis.

Construction of acid-base bifunctional covalent organic frameworks via Doebner reaction for catalysing cascade reaction

We report herein a series of quinoline-4-carboxylic acid linked COFs via the multicomponent one-pot in situ Doebner reaction. The obtained acid-base bifunctional COFs are chemically stable and can highly promote one-pot cascade deacetalization-Knoevenagel condensation reaction in a heterogeneous way under solvent-free conditions.

Confinement synthesis in porous molecule-based materials: a new opportunity for ultrafine nanostructures

A balance between activity and stability is greatly challenging in designing efficient metal nanoparticles (MNPs) for heterogeneous catalysis. Generally, reducing the size of MNPs to the atomic scale can provide high atom utilization, abundant active sites, and special electronic/band structures, for vastly enhancing their catalytic activity. Nevertheless, due to the dramatically increased surface free energy, such ultrafine nanostructures often suffer from severe aggregation and/or structural degradation during synthesis and catalysis, greatly weakening their reactivities, selectivities and stabilities. Porous molecule-based materials (PMMs), mainly including metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and porous organic polymers (POPs) or cages (POCs), exhibit high specific surface areas, high porosity, and tunable molecular confined space, being promising carriers or precursors to construct ultrafine nanostructures. The confinement effects of their nano/sub-nanopores or specific binding sites can not only effectively limit the agglomeration and growth of MNPs during reduction or pyrolysis processes, but also stabilize the resultant ultrafine nanostructures and modulate their electronic structures and stereochemistry in catalysis. In this review, we highlight the latest advancements in the confinement synthesis in PMMs for constructing atomic-scale nanostructures, such as ultrafine MNPs, nanoclusters, and single atoms. Firstly, we illustrated the typical confinement methods for synthesis. Secondly, we discussed different confinement strategies, including PMM-confinement strategy and PMM-confinement pyrolysis strategy, for synthesizing ultrafine nanostructures. Finally, we put forward the challenges and new opportunities for further applications of confinement synthesis in PMMs.

Porous organic polymers for light-driven organic transformations

As a new generation of porous materials, porous organic polymers (POPs), have recently emerged as a powerful platform of heterogeneous photocatalysis. POPs are constructed using extensive organic synthesis methodologies, with various functional organic units being connected via high-energy covalent bonds. This review systematically presents the recent advances in POPs for visible-light driven organic transformations. Herein, we firstly summarize the common construction strategies for POP-based photocatalysts based on two major approaches: pre-design and post-modification; secondly, we categorize and summarize the synthesis methods and organic reaction types for constructing various types of POPs. We then classify and introduce the specific reactions of current light-driven POP-mediated organic transformations. Finally, we outline the current state of development and the problems faced in light-driven organic transformations by POPs, and we present some perspectives to motivate the reader to explore solutions to these problems and confront the present challenges in the development process.

Near-Infrared Photothermal Catalysis for Enhanced Conversion of Carbon Dioxide under Mild Conditions

Enhanced conversion of carbon dioxide (CO₂) for cycloaddition with epoxide derivatives is highly desired in organic synthesis and green chemistry, yet it is still a challenge to obtain satisfactory activity under mild reaction conditions of temperature and pressure. For this purpose, an unexploited strategy is proposed here by incorporating near-infrared (NIR) photothermal properties into multicomponent catalysts. Through the electrostatic adsorption of Co- or Ce-substituted polyoxometalate (POM) clusters on the surface of graphene oxide (GO) with covalently grafted polyethyleneimine (PEI), a series of composite catalysts POMs@GO-PEI are prepared. The structural and property characterizations demonstrate the synergistic advantages of the catalysts bearing Lewis acids and bases and local NIR photothermal heating from the GO matrix for dramatically enhanced CO₂ cycloaddition. Noticeably, while the turnover frequency increases up to 2718 h^-1, the heterogeneous catalysts exhibit photothermal stability and recyclability. With this method, the onsite NIR photothermal transformation becomes extendable to more green reaction processes.

Photothermal Chemistry Based on Solar Energy: From Synergistic Effects to Practical Applications

With the development of society, energy shortage and environmental problems have become more and more outstanding. Solar energy is a clean and sustainable energy resource, potentially driving energy conversion and environmental remediation reactions. Thus, solar-driven chemistry is an attractive way to solve the two problems. Photothermal chemistry (PTC) is developed to achieve full-spectral utilization of the solar radiation and drive chemical reactions more efficiently under relatively mild conditions. In this review, the mechanisms of PTC are summarized from the aspects of thermal and non-thermal effects, and then the interaction and synergy between these two effects are sorted out. In this paper, distinguishing and quantifying these two effects is discussed to understand PTC processes better and to design PTC catalysts more methodically. However, PTC is still a little far away from practical. Herein, several key points, which must be considered when pushing ahead with the engineering application of PTC, are proposed, along with some workable suggestions on the practical application. This review provides a unique perspective on PTC, focusing on the synergistic effects and pointing out a possible direction for practical application.

Enhancing the photothermal conversion of tetrathiafulvalene-based MOFs by redox doping and plasmon resonance

Near-infrared (NIR) photothermal materials hold great promise for use in several applications, particularly in photothermal therapy, diagnosis, and imaging. However, current NIR responsive materials often show narrow absorption bands and low absorption efficiency, and have long response times. Herein, we demonstrate that the NIR absorption of tetrathiafulvalene-based metal–organic frameworks (MOFs) can be tuned by redox doping and using plasmonic nanoparticles. In this work, a MOF containing redox-active tetrathiafulvalene (TTF) units and Dy-carboxylate chains was constructed, Dy-m-TTFTB. The NIR absorption of the as-synthesized Dy-m-TTFTB was further enhanced by Ag⁺ or I₂ oxidation, transforming the neutral TTF into a TTF˙⁺ radical state. Interestingly, treatment with Ag⁺ not only generated TTF˙⁺ radicals, but it also formed Ag nanoparticles (NPs) in situ within the MOF pores. With both TTF˙⁺ radicals and Ag NPs, Ag NPs@Dy-m-TTFTB was shown to exhibit a wide range of absorption wavelengths (200–1000 nm) and also a high NIR photothermal conversion. When the system was irradiated with an 808 nm laser (energy power of 0.7 W cm⁻²), Ag NPs@Dy-m-TTFTB showed a sharp temperature increase of 239.8 °C. This increase was higher than that of pristine Dy-m-TTFTB (90.1 °C) or I₂ treated I₃⁻@Dy-m-TTFTB (213.0 °C).

The photo-response of the redox-active metal–organic framework has been systematically tuned by incorporating plasmonic Ag nanoparticles and tetrathiafulvalene radicals, resulting in efficient near-infrared photothermal conversion materials.

Efficient electrocatalytic carbon dioxide reduction with tetraphenylethylene- and porphyrin-based covalent organic frameworks

TPE-CoPor-COF shows high FECO (91–95%) in the range of −0.6 to −1.0 V, and a maximum jCO of −30.4 mA cm−2 at −1.0 V, exceeding most of reported COF-based electrocatalysts.

Construction of hydrophilic covalent organic frameworks and their fast and efficient adsorption of cationic dyes from aqueous solution

TFPB-Pa-SO3H COF and TFPB-BDSA COF were synthesized and showed fast adsorption of MLB (1 and 2 min) and high adsorption uptakes of CV (1559 and 1288 mg g−1). TFPB-Pa-SO3H COF as adsorbing material was used for the removal of dye molecules in real water samples.

Multi-sulfonated functionalized hydrophilic covalent organic framework for highly efficient dye removal from real samples

A hydrophilic covalent organic framework (BTA-BDSA-COF) was successfully erected by introducing multi-sulfonated groups into a covalent framework structure and it can be easily applied to capture the cationic dye in real water samples.

Covalent organic frameworks and multicomponent reactions: an endearing give-and-take relationship

Covalent organic frameworks (COFs) are porous and crystalline materials which are assembled by dynamic covalent bonds with two- or three-dimensional (2D or 3D) features. Unlike other polymers, COFs have significant...

BINOL-phosphoric acid and metalloporphyrin derived chiral covalent organic framework for enantioselective α-benzylation of aldehydes

The catalytic asymmetric α-benzylation of aldehydes represents a highly valuable reaction for organic synthesis. For example, the generated α-heteroarylmethyl aldehydes, such as (R)-2-methyl-3-(pyridin-4-yl)propanal ((R)-MPP), are an important class of synthons...

Anisotropic nanomaterials for asymmetric synthesis

The production of enantiopure chemicals is an essential part of modern chemical industry. Hence, the emergence of asymmetric catalysis led to dramatic changes in the procedures of chemical synthesis, and now it provides the most advantageous and economically executable solution for large-scale production of chiral chemicals. In recent years, nanostructures have emerged as potential materials for asymmetric synthesis. Indeed, on the one hand, nanomaterials offer great opportunities as catalysts in asymmetric catalysis, due to their tunable absorption, chirality, and unique energy transfer properties; on the other hand, the advantages of the larger surface area, increased number of unsaturated coordination centres, and more accessible active sites open prospects for catalyst encapsulation, partial or complete, in a nanoscale cavity, pore, pocket, or channel leading to alteration of the chemical reactivity through spatial confinement. This review focuses on anisotropic nanomaterials and considers the state-of-the-art progress in asymmetric synthesis catalysed by 1D, 2D and 3D nanostructures. The discussion comprises three main sections according to the nanostructure dimensionality. We analyze recent advances in materials and structure development, discuss the functional role of the nanomaterials in asymmetric synthesis, chirality, confinement effects, and reported enantioselectivity. Finally, the new opportunities and challenges of anisotropic 1D, 2D, and 3D nanomaterials in asymmetric synthesis, as well as the future prospects and current trends of the design and applications of these materials are analyzed in the Conclusions and outlook section.

Photocatalytic Activity of Supported Metal Nanoparticles and Single Atoms

Photocatalysis has been known as one of the promising technologies due to its eco-friendly nature. However, the potential application of many photocatalysts is limited owing to their large bandgaps and inefficient use of the solar spectrum. One strategy to overcome this problem is to combine the advantages of heteroatom-containing supports with active metal centers to accurately adjust the structural parameters. Metal nanoparticles (MNPs) and single atom catalysts (SACs) are excellent candidates due to their distinctive coordination environment which enhances photocatalytic activity. Metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and carbon nitride (g-C₃ N₄ ) have shown great potential as catalyst support for SACs and MNPs. The numerous combinations of organic linkers with various heteroatoms and metal ions provide unique structural characteristics to achieve advanced materials. This review describes the recent advancement of the modified MOFs, COFs and g-C₃ N₄ with SACs and NPs for enhanced photocatalytic applications with emphasis on environmental remediation.

3D Hydrazone-Functionalized Covalent Organic Frameworks as pH-Triggered Rotary Switches

The property expansion of 3D functionalized covalent organic frameworks (COFs) is important for developing their potential applications. Herein, the first case of 3D hydrazone-decorated COFs as pH-triggered molecular switches is reported, and their application in the stimuli-responsive drug delivery system is explored. These functionalized COFs with hydrazone groups on the channel walls are obtained via a multi-component bottom-up synthesis strategy. They exhibit a reversible E/Z isomerization at various pH values, confirmed by UV-vis absorption spectroscopy and proton conduction. Remarkably, after loading cytarabine (Ara-C) as a model drug molecule, these pH-responsive COFs show an excellent and intelligent sustained-release effect with an almost fourfold increase in the Ara-C release at pH = 4.8 than at pH = 7.4, which will effectively improve drug-targeting. Thus, these results open a way toward designing 3D stimuli-responsive functionalized COF materials and promote their potential application as drug carriers in the field of disease treatment.

Metalloporphyrin and Ionic Liquid-Functionalized Covalent Organic Frameworks for Catalytic CO2 Cycloaddition via Visible-Light-Induced Photothermal Conversion

We report the construction of a porphyrin and imidazolium-ionic liquid (IL)-decorated and quinoline-linked covalent organic framework (COF, abbreviated as COF-P1-1) via a three-component one-pot Povarov reaction. After post-synthetic metallization of COF-P1-1 with Co(II) ions, the metallized COF-PI-2 is generated. COF-PI-2 is chemically stable and displays highly selective CO₂ adsorption and good visible-light-induced photothermal conversion ability (ΔT = 26 °C). Furthermore, the coexistence of Co(II)-porphyrin and imidazolium-IL within COF-PI-2 has guaranteed its highly efficient activity for CO₂ cycloaddition. Of note, the needed thermal energy for the reactions is derived from the photothermal conversion of the Co(II)-porphyrin COF upon visible-light irradiation. More importantly, the CO₂ cycloaddition herein is a "window ledge" reaction, and it can proceed smoothly upon natural sunlight irradiation. In addition, a scaled-up CO₂ cycloaddition can be readily achieved using a COF-PI-2@chitosan aerogel-based fixed-bed model reactor. Our research provides a new avenue for COF-based greenhouse gas disposal in an eco-friendly and energy- and source-saving way.