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In this study, imidazolium‐based multifunctional ionic polymer (IP 1–IP 3) series, co‐incorporated with phenolic hydroxyl groups as hydrogen bond donors (HBDs) and Cl− as nucleophiles, are synthesized by a facile quaternization method. The physicochemical characterizations of these IPs are systematically examined by using FTIR, XPS, BET, TGA, CO2‐TPD, SEM with elemental mapping and TEM methods. Their catalytic activities are evaluated toward the conversion of carbon dioxide (CO2) and epoxides into cyclic carbonates under solvent‐ and additive‐free environments. Apart from the synergy effect between HBDs and Cl−, it is found that the types of the spacer linking the two imidazole units in the diimidazole precursors (L1–L3) also play an important role in the catalytic activity. And IP 2, with a pyridine spacer as a Lewis base site, exhibits the best catalytic performance under solvent‐free mild conditions i. e., atmospheric pressure CO2, 80 °C, and 5 h. Notably, the catalyst demonstrates a good substrate applicability. Furthermore, IP 2 exhibited good reusability, stability, and it can be recycled for ten successive runs with stable and potential catalytic activity. This study provides an alternative route to construct IPs with efficient activity for CO2 catalytic conversion and fixation under mild‐conditions. [ABSTRACT FROM AUTHOR]

A stable iron(III) complex with the cross‐bridged cyclam 4,11‐dimethyl‐1,4,8,11‐tetraazabicyclo[6.6.2]hexadecane catalyzes the epoxidation of aromatic alkenes and the fixation of CO2 into cyclic carbonates. Best results were obtained for styrene conversion to styrene carbonate. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of carbamates from bio‐derived cyclic carbonates and amines by using 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) as an organocatalyst is reported. This methodology led to the preparation of a wide range of bio‐sourced hydroxyurethanes from furan‐, carvone‐ and limonene‐based scaffolds under solvent‐free and mild reaction conditions. Moreover, a comprehensive analysis of the process allowed us to optimize the catalyst loading with little or no impact on the process regioselectivity. [ABSTRACT FROM AUTHOR]

The synthesis of bio‐derived cyclic carbonates is attracting a lot of attention as the incorporation of bio‐derived functionality into these compounds provides the opportunity to prepare previously unknown structures, whilst also improving their sustainability profiles. This study presents a facile preparation of diastereomerically pure bio‐derived cyclic carbonates displaying a range of optical rotation values. These compounds are obtained from glycidol, amino acids and CO2 in a facile two‐step approach. Initially, the diastereomerically pure amino acid functionalised epoxides are prepared through a robust Steglich esterification of enantiopure glycidol (R or S) and an amino acid (D or L). Thereafter, in a second step, cycloaddition of the epoxide with CO2 results in the retention of the initial stereochemistry of the epoxide, furnishing novel diastereomerically pure and optically active cyclic carbonate products. A DFT study has explained the basis of this observed retention of configuration for these compounds. Further, results from this DFT study also provide new mechanistic information concerning a co‐catalyst‐free cycloaddition reaction starting from glycidol when using the gallium‐catalyst, which is found to operate through metal‐ligand cooperativity. [ABSTRACT FROM AUTHOR]

The design of molecular scaffolds bearing multiple functional groups for the activation and ring‐opening of epoxides is a crucial challenge for the synthesis of efficient homogeneous and heterogeneous catalysts that are used for the cycloaddition reaction of CO2 to epoxides. Traditional approaches to prepare such multifunctional catalysts often imply multistep synthetic procedures and expensive building blocks. In this work we show that bifunctional catalysts for the cycloaddition of CO2 to epoxides bearing a Lewis acid metal and a quaternary ammonium halide group can be prepared in just two steps starting from an opportunely designed epoxide precursor by using inexpensive substrates. Such a readily accessible catalyst was applied for the cycloaddition of CO2 to a series of epoxides under atmospheric conditions generally leading to quantitative substrate conversion and high carbonate selectivities. Importantly, we also show that the epoxide‐driven concept developed for the preparation of the molecular catalyst, could be applied to prepare recyclable heterogeneous systems for the target cycloaddition reaction. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A Ru(II)‐catalyzed ortho allylation reaction of N‐aryl‐7‐azaindole with readily available 2‐methylidene cyclic carbonate has been developed. This reaction is an effective pathway for synthesizing 7‐azaindole derivatives with a wide scope of substrates and high yields. In addition, the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates, highlighting the practicality of this strategy for synthesis. [ABSTRACT FROM AUTHOR]

The anthropogenic carbon dioxide (CO2) fixation and various engineering strategies are gaining very significant attention because of the expansion of the net‐zero carbon environment in the atmosphere. Herein, we designed a sodium aluminate@γ‐alumina (NaAlO2@γ‐Al2O3) catalyst by a simple and facile precipitation and impregnation tactics. A series of different weight percentage NaAlO2@γ‐Al2O3 materials were successfully synthesized and well characterized by using advanced analytical and spectroscopic techniques such as TGA, XRD, FE‐SEM, TEM/HR‐TEM, FT‐IR, Raman, TPD, and XPS analysis. The NaAlO2@γ‐Al2O3 catalyst was employed as a competent catalyst for the CO2 fixation under atmospheric pressure reaction conditions. The catalytic activity results evidently revealed that the cycloaddition reaction successfully achieved 94% styrene oxide conversion and 93% selectivity, along with an 87% yield of the styrene carbonate at 120 °C for 6 h. Furthermore, we comprehensively examined the effect of different reaction parameters such as the effect of sodium aluminate amount, co‐catalyst amount, temperature, and time for CO2 fixation reaction. Additionally, different terminal and internal epoxides were tested under optimized reaction conditions and achieved moderate to excellent yield of the desired cyclic carbonate products. Interestingly, a plausible reaction mechanism was proposed for the styrene carbonate synthesis using NaAlO2@γ‐Al2O3 catalyst surface with the support of characterization and experimental results. Remarkably, the NaAlO2@γ‐Al2O3 catalyst could be easily recoverable and successfully recyclable up to six consecutive cycles without declining its initial catalytic activity along with stable structural and physicochemical properties. [ABSTRACT FROM AUTHOR]

Fixing the greenhouse gas CO2 through epoxide helps to mitigate worldwide ecological troubles. The applications of metal‐free and solvent‐free catalysts remain a challenge for CO2 catalytic conversion. In this work, an array of quaternary ammonium salts derived from polyethyleneimine with hydroxyl groups ([PEI‐GDMAB‐Cn]Br) were constructed by the reaction of branched PEI with a molecular weight of 10000 and glycidyl alkyl dimethylammonium bromide. A range of experiments were designed to demonstrate that [PEI‐GDMAB‐Cn]Br can be considered as a valid metal‐free and solvent‐free homogeneous catalyst for the CO2‐epoxide cycloaddition reaction. Among of [PEI‐GDMAB‐Cn]Br, [PEI‐GDMAB‐C18]Br catalyzed the model reaction of CO2 and epichlorohydrin under optimized reaction conditions (T=80 °C, 1.0 atm CO2, catalyst 1 mol%, ECH 15 mmol, 16 h) and the conversion achieved at 97.5 %. Moreover, the catalyst exhibited stable reusability and broad substrate applicability, which was used in the following cycle succinctly, because of self‐separated properties by temperature control. The [PEI‐GDMAB‐C18]Br catalyzed reaction process was detected as a pseudo‐first‐order reaction after kinetic studies and an Ea was calculated to be 50.65 kJ/mol. A combinatorial catalytic mechanism of hydrogen bonding and bromide ions is suggested to explain the remarkable catalytic performance of this bifunctional catalyst. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A catalytic domino, three‐component reaction has been developed for the transformation of carbon dioxide into functionalized six‐membered cyclic carbonates. The catalytic process combines an initial carboxylative cyclization of β‐epoxy alcohols followed by an oxa‐Michael reaction affording an unparalleled scope of heterocyclic structures. The wide range of functional groups, including free‐alcohols, empowers the access to a range of products including C11‐oxo‐based bicyclic heterocycles. The versatility of these functionalized carbonates is further complemented by a series of synthetic diversifications. Control experiments are consistent with the first step of this domino process being promoted by a binary Lewis acid/base catalyst, while the second stage only requires catalytic base. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Polyhydroxyurethanes (PHUs) have received considerable attention in the last decade as potential alternatives to traditional phosgene‐based polyurethanes (PUs). The development of suitable 5CC (five membered‐ring cyclic carbonate) precursors bearing multiple carbonate moieties (multi‐5CCs) is a key requisite for preparing PHUs by polyaddition reaction with bis‐ or polyamines. Producing sustainable PHUs from CO2‐based five‐membered cyclic carbonates (5CCs) obtained from biobased epoxides is a valuable strategy to bridge CO2 utilization and the upcycling of renewable substrates. In this context, while many multi‐5CC monomers reported in the literature are oil‐based, recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO2 and renewable resources such as fatty acids and vegetable oils, lignin, terpenes, and sugars. In this work, recent crucial advances (2019—2023) on PHUs prepared from bis‐ and multi‐5CCs produced from CO2 and (partially/potentially) biobased substrates are reviewed with respect to their synthesis, thermal and mechanical properties, and their recent, emerging applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Polyhydroxyurethanes (PHUs) have received considerable attention in the last decade as potential alternatives to traditional phosgene‐based polyurethanes (PUs). The development of suitable 5CC (five membered‐ring cyclic carbonate) precursors bearing multiple carbonate moieties (multi‐5CCs) is a key requisite for preparing PHUs by polyaddition reaction with bis‐ or polyamines. Producing sustainable PHUs from CO2‐based five‐membered cyclic carbonates (5CCs) obtained from biobased epoxides is a valuable strategy to bridge CO2 utilization and the upcycling of renewable substrates. In this context, while many multi‐5CC monomers reported in the literature are oil‐based, recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO2 and renewable resources such as fatty acids and vegetable oils, lignin, terpenes, and sugars. In this work, recent crucial advances (2019—2023) on PHUs prepared from bis‐ and multi‐5CCs produced from CO2 and (partially/potentially) biobased substrates are reviewed with respect to their synthesis, thermal and mechanical properties, and their recent, emerging applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates, whose recent reactivity has been expanded towards the formation of tailor‐made engineering polymers. This minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO2 based synthons. In addition, their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring‐opening of the carbonate monomers. Future perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO2. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Carbon dioxide can be converted into functional heterocycles known as cyclic carbonates, whose recent reactivity has been expanded towards the formation of tailor‐made engineering polymers. This minireview gives an overview of the most topical developments in this area with a special focus on the synthetic methods employed to prepare these CO2 based synthons. In addition, their application potential in the area of polymer science using a variety of polymerization techniques is discussed that have in common the ring‐opening of the carbonate monomers. Future perspectives are provided that provide impetus for the scientific communities aligning research to the use of sustainable processes for polymers from recyclable carbon sources such as CO2. [ABSTRACT FROM AUTHOR]

The effective chemical valorization of CO2 by means of its conversion into valuable products is now more than ever a topic of considerable interest. It is on that basis that herein we have chosen the conversion of CO2 and epoxides to cyclic carbonates as a convenient route to achieve this goal. A new bifunctional (Lewis acid/nucleophile) heterogeneous material, TSP‐AlCl‐PhospBr, was designed in order to guarantee a close proximity between the two active sites that can cooperate to the activation and opening of the epoxide ring. The prepared copolymer has been extensively characterized using various spectroscopic and analytical techniques. As a heterogeneous catalyst, it enables efficient chemical conversion of CO2 and epoxides, even at low temperatures, down to 30 °C, without the use of solvents. In particular, the catalyst demonstrates high turnover numbers (TON) and frequency values (TOF). Recyclability studies on TSP‐AlCl‐PhospBr have shown its stability and reusability for consecutive cycles without the need of reactivation procedures. [ABSTRACT FROM AUTHOR]

One‐pot tandem synthesis of cyclic carbonates from olefins and CO2 is becoming one of the most potential strategies to fix CO2 and yield high value chemicals. However, this reaction route is in need of high performing catalysts with multifunctionalized catalytic sites in single material which is still a big challenge in one‐pot community. In this term, we combined dimension reduction and surface modification strategies to fabricate a MOF/metal complex composite, that is, Zr‐BTB/PA‐Co. In this composite, the increased Lewis base sites is capable of boosting the adsorption and activation of CO2, which further acted as nucleophilic groups to activate epoxides, while the 2D matrix offered accessible intrinsic Lewis acid sites. These advantages synergistically led to superior catalytic performance of Zr‐BTB/PA‐Co for catalyzing one‐pot reaction of olefins and CO2 under mild conditions (80°C, 1 bar, 12 h and co‐catalyst/solvent free), and even impressive catalytic activity when using CO2 directly from air. [ABSTRACT FROM AUTHOR]

In this work, two ionic liquids (ILs) immobilized metal‐organic frameworks (MOFs), Fe‐MIL‐101‐3N(BuBr) and Fe‐MIL‐101‐N(Bnme2)Br, were obtained by modifying amino groups in Fe‐MIL‐101‐NH2 with bromobutane and quaternary ammonium salt. The ionic liquid immobilized MOFs have Lewis acid sites (Fe3+) and nucleophilic sites (Br−), which can synergistically catalyze the cycloaddition reaction of CO2 and epoxides. Various cyclic carbonate derivatives were obtained in excellent yields under the optimal conditions. Additionally, we found that Fe‐MIL‐101‐N(Bnme2)Br exhibited the highest catalytic activity and it can be easily recovered and reused for at least 5 times without loss of catalytic activity. Our method of preparing bifunctional catalysts provides a new approach to design catalysts for the chemical conversion of CO2. [ABSTRACT FROM AUTHOR]

Undecylenic acid, glycerol, and CO2 were used as building blocks for obtaining a fully bio‐based carbonated monomer, useful for polyurethanes. The functionality of the monomer was close to 3 cyclic carbonates/mol, located in terminal positions. In a first stage, a synthetic triglyceride was obtained with 99% selectivity by esterification of glycerol and undecylenic acid at 160°C. The triglyceride was then epoxidized using H2O2 and Amberlyst 15 or Amberlite IR‐120 acidic exchange resins at 57°C. The selectivity to epoxide was kept constant at 98% using Amberlite IR‐120. Terminal cyclic carbonates were then inserted through epoxide moieties under mild conditions by the chemical fixation of CO2 at 80°C and 6 MPa in 6 h. A complete conversion was obtained in 6 h reaction while the selectivity to carbonate groups was near to 99% during all the reaction time. An elastomeric polyhydroxyurethane was obtained by aminolysis of the carbonated monomer with ethylenediamine at 70°C, affording a Young's modulus of 22.6 MPa and Tg of −15.2°C. The material showed a good thermal stability below 240°C. [ABSTRACT FROM AUTHOR]

Cyclic carbonates have received significant interests for uses as reagents, solvents, and monomers. The coupling reaction of epoxides with carbon dioxide (CO2) to produce cyclic carbonate is an attractive route which can significantly reduce greenhouse gas emissions and environmental hazards. Herein, a series of five indium chloride complexes supported by inden Schiff‐base ligands were reported along with four X‐ray crystal structures. The constrained five‐membered rings were added to the ligands to enhance the coordination of epoxides to the In metal. From the catalyst screening, In inden complex having tert‐butyl substituents and propylene backbone in combination with tetrabutylammonium bromide (TBAB) exhibited the highest catalytic activity (TON up to 1017) for propylene oxide/CO2 coupling reaction with >99 % selectivity for cyclic carbonate under solvent‐free conditions. In addition, the catalyst was shown to be active at atmospheric pressure of CO2 at room temperature. The catalyst system can be applied to various internal and terminal epoxide substrates to exclusively produce the corresponding cyclic carbonates. [ABSTRACT FROM AUTHOR]

Polymeric foams are widely used in many industrial applications due to their light weight and superior thermal, mechanical, and optical properties. Currently, increasing research efforts is being directed towards the development of greener foam formulations that circumvent the use of isocyanates/blowing agents that are commonly used in the production of foam materials. Here, a straightforward, one‐pot method is presented to prepare self‐blown polycarbonate (PC) foams by exploiting the (decarboxylative) S‐alkylation reaction for in situ generation of the blowing agent (CO2). The concomitant formation of a reactive alcohol intermediate promotes a cascade ring‐opening polymerization of the cyclic carbonates to yield a cross‐linked polymer network. It is shown that these hydroxyl‐functionalized polycarbonate‐based foams can be easily recycled into films through thermal compression molding. Furthermore, it is demonstrated that complete hydrolytic degradation of the foams is possible, thus offering the potential for zero‐waste materials. This straightforward and versatile process broadens the scope of isocyanate‐free, self‐foaming materials, opening a new pathway for next‐generation environmentally friendly foams. [ABSTRACT FROM AUTHOR]

The biocatalytic kinetic resolution of cyclic carbonates derived from glycerol is reported. A selection of 26 esterases and lipases was tested for the asymmetric hydrolysis of the model substrate (epichlorohydrin carbonate) in aqueous medium. Among them, Pig Liver Esterase and Novozym® 435 showed the best selectivity with E=38 and 49, respectively. Both enzymes were employed for the conversion of 12 glycerol derivatives under optimized conditions. The resolution of halogenated carbonates afforded the unconverted enantiomer in up to >99 : 1 er. Furthermore, Novozym® 435 was successfully recycled 10 times without significant loss of activity. Upscaling and isolation of the chiral carbonate was also demonstrated. Subsequent conversion of this chiral building block allowed the direct one‐pot synthesis of (S)‐Guaifenesin, (S)‐Mephenesin and (S)‐Chlorphenesin in up to 89 % yield and 94 : 6 er. [ABSTRACT FROM AUTHOR]

Benzamide‐derived organochalcogens (chalcogen=S, Se, and Te) have shown promising interest in biological and synthetic chemistry. Ebselen molecule derived from benzamide moiety is the most studied organoselenium. However, its heavier congener organotellurium is under‐explored. Here, an efficient copper‐catalyzed atom economical synthetic method has been developed to synthesize 2‐phenyl‐benzamide tellurenyl iodides by inserting a tellurium atom into carbon‐iodine bond of 2‐iodobenzamides in one pot with 78–95 % yields. Further, the Lewis acidic nature of Te center and Lewis basic nature of nitrogen of the synthesized 2‐Iodo‐N‐(quinolin‐8‐yl)benzamide tellurenyl iodides enabled them as pre‐catalyst for the activation of epoxide with CO2 at 1 atm for the preparation of cyclic carbonates with TOF and TON values of 1447 h−1 and 4343, respectively, under solvent‐free conditions. In addition, 2‐iodo‐N‐(quinolin‐8‐yl)benzamide tellurenyl iodides have also been used as pre‐catalyst for activating anilines and CO2 to form a variety of 1,3‐diaryl ureas up to 95 % yield. The mechanistic investigation for CO2 mitigation is done by 125Te NMR and HRMS studies. It seems that the reaction proceeds via formation of catalytically active Te−N heterocycle, an ebtellur intermediate which is isolated and structurally characterized. [ABSTRACT FROM AUTHOR]

The reaction of carbon dioxide (CO2) with epoxide to generate cyclic carbonates is one of the most effective chemical fixation methods. The catalytic system significantly affects the carbon fixation efficiency of the reaction. Among the reported catalytic systems, porous materials as heterogeneous catalysts have attracted significant attention. This study aimed to summarize porous materials that catalyzed the conversion of CO2 into cyclic carbonates, including metal organic frameworks, covalent organic frameworks, poly(ionic) liquids, hyper crosslinked polymers, conjugated porous polymers and others. The study analyzed the catalytic properties of these materials and outlined future research directions. [ABSTRACT FROM AUTHOR]

The utilization of CO2 as building block for the production of cyclic carbonate is a promising route to simultaneously mitigate the global warming issue and obtain valuable commercial chemicals. In this work, the activity of nicotinamidium halide catalysts towards the CO2 conversion into cyclic carbonate has been explored by means of density functional theory (DFT) calculations. DFT calculations support the ability, suggested experimentally, of the pyridium α‐C−H proton of the catalysts to activate the epoxide ring via a hydrogen bond. Interestingly, DFT calculations underline the involvement of the n‐octyl substituent of the pyridyl ring in the epoxide activation, while the hydrogen atom of the amide group N−H is rather involved in the stabilization of the iodide trough electrostatic interactions. Moreover, the replacement of the pyridium α‐C−H proton with the bulkier methyl group leads to a different reaction mechanism. The calculated energy barriers well reproduce the experimental trends of the studied catalysts, and the computed activation barrier of 29.0 kcal/mol, relative to the ring opening step of the most active catalyst, is in line with the experimental working temperature of 80 °C. Those results shed light on the CO2 fixation reaction contributing to the development of more efficient catalytic systems. [ABSTRACT FROM AUTHOR]

An effective approach for tuning CO2 adsorption, activation and transformations of various epoxides in CO2 fixation reactions is introducing functional groups into the pores of metal‐organic frameworks (MOFs) through ligand modification. Herein, a novel ionic ligand, 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene‐biphenyl‐4,4′‐dicarboxylic acid (H2BPDC−[TBD]+Br−), was synthesized to construct derivatives of the cationic guanidinium‐containing Zr‐MOF (UiO67‐[TBD]+Br−) with free bromide ions, as multifunctional heterogeneous catalysts. The materials were characterized comprehensively by multiple techniques such as PXRD, FTIR, TGA, SEM, EDS, 1H NMR, 13C NMR, mass spectrometry (MS), elemental analysis, as well as N2 and CO2 adsorption measurements. The synthesized UiO67‐[TBD]+Br− exhibits an efficient heterogeneous catalytic performance in the CO2 fixation reaction with epoxides, with high yield and selectivity, under mild conditions (0.1 MPa CO2, 80 °C, without co‐catalyst and solvent). In addition, these catalysts display good thermal stability, recyclability and could be reused at least five times without a significant decrease in their catalytic performance. [ABSTRACT FROM AUTHOR]

The development of efficient bifunctional organocatalysts for the catalytic conversion of CO2 under mild conditions remains particularly challenging. Inspired by the synergistic mechanism of intramolecular Lewis acid‐base active sites, we report a series of bifunctional cross‐linked epoxy resin organocatalysts containing multiple active sites for the cycloaddition reaction of dilute CO2 with epoxides. These catalysts exhibit high reactivity and product selectivity (10 examples, >99 %) for the cycloaddition reactions of a variety of epoxides and CO2, and surprisingly, epichlorohydrin (ECH), can be converted under ambient temperature and pressure (25 °C, 1.0 bar) without co‐catalysts. 1H NMR, 13C NMR, 19F NMR and in situ IR studies suggest that the simultaneous and efficient activation of CO2 and epoxides is responsible for the improved catalytic activity. Upon an insightful investigation of the catalytic mechanism, this protocol will contribute to the development of efficient and environmentally friendly metal‐free catalysts. [ABSTRACT FROM AUTHOR]

The fixation of atmospheric CO2 into value‐added products is a promising methodology. A series of novel nickel(II) complexes of the type [Ni(L)(CH3CN)2](BPh4)21–5, where L=N,N‐bis(2‐pyridylmethyl)‐N′, N′‐dimethylpropane‐1,3‐diamine (L1), N,N‐dimethyl‐N′‐(2‐(pyridin‐2‐yl)ethyl)‐N′‐(pyridin‐2‐ylmethyl) propane‐1,3‐diamine (L2), N,N‐bis((4‐methoxy‐3,5‐dimethylpyridin‐2‐ylmethyl)‐N′,N′‐dimethylpropane‐1,3‐diamine (L3), N‐(2‐(dimethylamino) benzyl)‐N′,N′‐dimethyl‐N‐(pyridin‐2‐ylmethyl) propane‐1,3‐diamine (L4) and N,N‐bis(2‐(dimethylamino)benzyl)‐N′, N′‐dimethylpropane‐1,3‐diamine (L5) have been synthesized and characterized as the catalysts for the conversion of atmospheric CO2 into organic cyclic carbonates. The single‐crystal X‐ray structure of 2 was determined and exhibited distorted octahedral coordination geometry with cis‐α configuration. The complexes have been used as a catalyst for converting CO2 and epoxides into five‐membered cyclic carbonates under 1 atmospheric (atm) pressure at room temperature in the presence of Bu4NBr. The catalyst containing electron‐releasing −Me and ‐OMe groups afforded the maximum yield of cyclic carbonates, 34% (TON, 680) under 1 atm air. It was drastically enhanced to 89% (TON, 1780) under pure CO2 gas at 1 atm. It is the highest catalytic efficiency known for CO2 fixation using nickel‐based catalysts at room temperature and 1 atm pressure. The electronic and steric factors of the ligands strongly influence the catalytic efficiency. Furthermore, all the catalysts can convert a wide range of epoxides (ten examples) into corresponding cyclic carbonate with excellent selectivity (>99%) under this mild condition. [ABSTRACT FROM AUTHOR]

Hypercrosslinked polymers (HCPs) constructed by Friedel‐Crafts reaction have drawn increasing attention in recent decades, but their multifunctionalization remains a huge challenge. Herein, a series of aluminum‐porphyrin‐based hypercrosslinked ionic polymers have been successfully synthesized by direct knitting approach without additional electrophilic comonomers, which involves the copolymerization of neutral porphyrin monomers and ionic building. By increasing the connected nodes numbers of ionic monomers, the introduction of abundant tetraphenylmethane fragements into the porphyrin backbones endows them with high‐density ionic active sites. Accordingly, the well‐matched molar ratios of aluminum sites to nucleophilic chloride anions that work synergistically for CO2/epoxide coupling can be achieved. Al‐HIP‐2 with flexible ionic pendants and a high Al/Cl ratio allows CO2 cycloaddition to be performed at ambient conditions or with diluted CO2; while Al‐HIP‐3 with rigid ionic moieties and a relatively low Al/Cl ratio exhibits higher specific surface area and stronger CO2 capture ability. Therefore, this co‐condensation strategy provides a simple and feasible pathway for adjusting the reactivity ratios of comonomers via simple structural changes in the knitting process, thus achieving the rational construction of multifunctionalized HCPs for CO2 capture and in‐situ conversion to cyclic carbonates. [ABSTRACT FROM AUTHOR]

Aiming highly efficient conversion of greenhouse gas CO2 to cyclic carbonates, a biomass Ru(III) Schiff base complex catalyst (SalRu) was constructed by employing a derivative of Lignin degradation (5‐aldehyde vanillin). The SalRu catalyst had a remarkable conversion for epoxides into corresponding cyclic carbonates even at atmospheric pressure of CO2 without the presence of co‐catalyst. As the condition at 120 °C and 2 MPa CO2 the conversion reached to 94 % with selectivity at 99 % after 8 h. 32 % cyclic carbonate production was obtained even under 0.2 MPa CO2 pressure. The epoxide activation and ring opening, CO2 insertion and cyclic carbonate formation were illuminated explicitly through the of characteristic absorption peaks changing, which further providing direct and visual evidence for the mechanism proposing. This study has important theoretical significance for the comprehensive utilization of environmental pollutants and energy. [ABSTRACT FROM AUTHOR]

The synthesis of non‐racemic 5‐membered cyclic carbonates from abundant alcohols is reported. Conversion of the alcohol into an azanyl carbonate is followed by a chiral‐at‐ruthenium catalyzed cyclization to provide chiral cyclic carbonates in yields of up to 95 % and with up to 99 % ee. This new synthetic method is proposed to proceed through a nitrene‐mediated intramolecular C(sp3)−H oxygenation which includes an unusual 1,7‐hydrogen atom transfer within a ruthenium nitrene intermediate. The method is applicable to the synthesis of non‐racemic chiral mono‐, di‐ and trisubstituted cyclic alkylene carbonates. [ABSTRACT FROM AUTHOR]

The development of an efficient, easily prepared, and environmentally friendly catalyst is important for the coupling reaction between CO2 and epoxides. Herein, novel TBAB‐based (tetrabutylammonium bromide, TBAB) deep eutectic solvents (DESs) have been applied in the transformation of CO2 and epoxides into cyclic carbonates with exhibit high activity and selectivity under mild conditions (25 °C, 8 bar CO2), The excellent activity and versatility of the TBAB‐based DESs can be attributed to the hydrogen‐bond interaction between the TBAB and citric acid. Due to hydrogen‐bond interaction between −OH and Br−, the Br− becomes more flexible and facilitates the nucleophilic ring‐opening process. The density functional theory (DFT) method has been used to explore the mechanism governing the CO2 cycloaddition reaction. DFT results imply that intramolecular hydrogen bonding and the flexible nucleophilic Br− anion can significantly accelerate the ring‐opening process. Hence, the ring‐closure reaction may be the rate‐determining step in the CO2 cycloaddition reaction catalyzed by TBAB‐based DESs. Both the experimental and computational results have demonstrated that the synergistic effect between the −OH and Br− in the TBAB‐based DESs play a significant role in the acceleration of the ring‐opening process of the CO2 cycloaddition reaction. [ABSTRACT FROM AUTHOR]

Conversion of β‐elemene into new β‐elemene dicarbonates through epoxidation and halide salt‐catalyzed CO2 cycloaddition reactions is reported. Step‐growth polyaddition of this dicarbonate to five different, commercial diamines was investigated under neat conditions at 150 °C yielding non‐isocyanate‐based low molecular weight oligo(hydroxyurethane)s with 1.3≤Mn≤6.3 kDa and 1.3≤Ð≤2.1, and with glass transition temperatures ranging from −59 to 84 °C. The preparation of one selected polyhydroxyurethane material, obtained in the presence of Jeffamine® D‐2010 was scaled‐up to 43 g. The latter, when combined in a formulation using Irgacure® 2100 and Laromer® LR 9000 allowed the preparation of coatings that were analyzed with several techniques showing the potential of these biobased oligourethanes towards the preparation of commercially relevant materials. [ABSTRACT FROM AUTHOR]

Currently world is facing a serious environmental concern in the steady increase in the CO2 concentration in air and this is directly related to climate change. Thus, successful utilization of CO2 into valuable chemicals is one of our primary goals. Herein, we have successfully fabricated a porous organic polymer PDVTA‐1 via the free radical cross coupling between divinylbenzene and triallyl amine. This porous polymer is found to possess permanent porosity with a very high BET surface area of 915 m2 g−1. Furthermore, upon sulfonation PDVTA‐1 is found to be very active as a bifunctional catalyst with a high BET surface area of 477 m2g‐1 and it efficiently catalyzes the synthesis of methanol and diols from CO2 and respective epoxide under solvent‐free process and relatively milder reaction conditions. In this method 34% yield of methanol and 53% propylene glycol are produced from CO2 and propylene oxide by using considerably mild reducing agent Et3SiH. [ABSTRACT FROM AUTHOR]

A nanotubular porous porphyrin‐based network (NT‐PPN) was prepared through Friedel–Crafts alkylation polyreaction of meso‐tetraphenylporphyrin iron chloride and subsequent demetalization reaction with concentrated hydrochloric acid. As a superior support, NT‐PPN was decorated with Ag nanoparticles to generate the desired catalyst (Ag@NT‐PPN). Ag@NT‐PPN had a high BET surface area with plentiful hierarchical porosity, considerable CO2 adsorption uptake, as well as high CO2/N2 adsorption selectivity. In the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), Ag@NT‐PPN exhibited excellent catalytic performance for the solvent‐free synthesis of α‐alkylidene cyclic carbonates from propargyl alcohols and CO2 at 30 °C. Ag@NT‐PPN also displayed robust constancy, excellent recyclability, and acceptable substrate expansibility for this reaction. Moreover, low concentration of CO2 derived from mixed gas (15% CO2+85% N2 in volume) was positively amenable to this catalytic protocol. This work might offer an opportunity to design metal NPs‐based heterogeneous catalysts and provide a promising candidate for application in the transformation of CO2 into valuable cyclic carbonates. [ABSTRACT FROM AUTHOR]

The synthesis of three bifunctional phosphonium salts bearing perfluorinated side chains is reported. These compounds were employed as catalysts for the synthesis of cyclic carbonates from epoxides and CO2. The most efficient catalyst comprised a phenolic substructure and allowed the synthesis of various carbonates at room temperature and a CO2 pressure as low as 0.1 MPa. The reaction could be performed in perfluorodecalin which in some cases led to improved yields and facilitated the separation of the catalyst. Furthermore, the isolation from the reaction mixture and recyclability of two catalysts was evaluated. However, the activity of the recycled catalysts gradually decreases due to partial decomposition. In total 16 cyclic carbonates were prepared in yields up to 97%. [ABSTRACT FROM AUTHOR]

A series of bifunctional rare‐earth metal complexes bearing zwitterionic amino‐bis(phenolato) ligands were synthesized and structurally characterized. These complexes were applied as catalysts for the synthesis of cyclic carbonates from epoxides and CO2. Lanthanum complex 1La was most active, converting terminal epoxides into the cyclic carbonates in moderate to excellent yields at 40 °C in the presence of 1 bar CO2. The catalyst was also recycled five runs without loss of catalytic activity. The kinetics of the cycloaddition of CO2 and epichlorohydrin (ECH) catalyzed by complex 1La were investigated. According to the Arrhenius equation, the activation barrier for cyclic carbonate formation is determined to be 8.29±0.68 kcal/mol. [ABSTRACT FROM AUTHOR]

A new catalytic route has been developed for the coupling of epoxides and CO2 affording polymerizable six‐membered bicyclic carbonates. Cyclic epoxides equipped with a β‐positioned OH group can be transformed into structurally diverse bicyclic cyclic carbonates in good yields and with high selectivity. Key to the chemo‐selectivity is the difference between the reactivity of syn‐ and anti‐configured epoxy alcohols, with the latter leading to six‐membered ring carbonate formation in the presence of a binary AlIII aminotriphenolate complex/DIPEA catalyst. X‐ray analyses show that the conversion of the syn‐configured substrate evolves via a standard double inversion pathway providing a five‐membered carbonate product, whereas the anti‐isomer allows for activation of the oxirane unit of the substrate opposite to the pendent alcohol. The potential use of these bicyclic products is shown in ring‐opening polymerization offering access to rigid polycarbonates with improved thermal resistance. [ABSTRACT FROM AUTHOR]

A new bifunctional biobased molecule, the carbonated methyl ester of ricinoleic acid maleate (CME‐RAM), useful for polyurethanes, was obtained from castor oil and CO2. This molecule bears carbonate and maleate functionalities that can participate, respectively, in aza‐Michael and aminolysis reactions. Maleate moieties are strong Michael acceptors and they were introduced into the fatty molecule using mild conditions. The synthetic steps include maleinization of castor oil followed by the simultaneous esterification and transesterification at 60°C. The subsequent stages were the epoxidation with acidic resins and the carbonation with CO2. The best results for epoxidation were obtained using Amberlite IR‐120 as catalyst at 48°C (84% conversion of double bonds). The carbonation of the oxirane ring with CO2 at 130°C, 6 MPa CO2 and 6 h reaction afforded 98% conversion of epoxides. It was demonstrated that aza‐Michael reaction of maleate groups was faster than aminolysis of carbonate groups, using hexylamine as a model molecule. CME‐RAM was oligomerized with ethylenediamine and used in the formulation of a conventional rigid polyurethane. Petrochemical polyol and isocyanate can be partially replaced by this bio‐based oligomer, producing a rigid material with a high percentage of green component and good mechanical properties. [ABSTRACT FROM AUTHOR]

The rising global warming and associated climate change demand efficient tactics to reduce CO2 concentration in the atmosphere. Conversion of epoxides to cyclic carbonates utilizing CO2 is a promising and sustainable approach towards CO2 fixation. However, the inert nature of CO2 and high activation energy requirement for the particular reaction necessitate the use of efficient catalysts. In this work, we have designed and developed a heterogeneous catalyst using catechol functionalized guanidinium based ligands (L1) and Fe(III) ions to perform the CO2 fixation reaction. The resulting amorphous material (Fe−L1) possesses metal‐organic network as revealed through different characterization methods. The optimized catalyst Fe−L1 is efficient for the conversion of a variety of epoxides into their corresponding cyclic carbonates in very good yield (>80 %). The reactions were performed under atmospheric pressure without solvent and external additives (e. g., TBAI or KI). The investigation of the mechanistic pathway indeed validates the synergistic effect of metal and halide ions that leads to the efficient conversion of different epoxides into cyclic carbonates. Furthermore, no significant loss in the catalytic activity of the Fe−L1 is noticed up to six cycles. The post catalytic analyses clearly indicate the robust nature of the catalyst. The developed one component bifunctional catalytic system can pave way towards transition to sustainable carbon capture and conversion. [ABSTRACT FROM AUTHOR]

Palladium‐catalyzed decarboxylative cycloadditions have emerged as highly effective methods for constructing structurally diverse carbo‐ and heterocycles because of the formation of at least two carbon‐carbon or carbon‐heteroatom bonds in a single step. It is of great interest to chemists that this type of cycloaddition reactions possesses some special advantages such as high reactivity, exclusive regioselectivity, and good functional group compatibility. Based on these qualities, palladium‐catalyzed decarboxylative cycloadditions present strong ability in synthetic chemistry and have been flourished especially in the last five years. In this review, the achievements in palladium‐catalyzed decarboxylative cycloadditions involving cyclic carbonates, carbamates, and lactones for accessing oxacyclo‐, azacyclo‐ and carbocyclic compounds are addressed. Mechanistic insights and some synthetic applications toward the synthesis of natural products are discussed. The challenges and opportunities of this field are also outlined. [ABSTRACT FROM AUTHOR]

Haloazaphosphatranes are the halogenated parents of proazaphosphatranes, also known as Verkade's superbase. While the synthesis of iodo‐, bromo‐ and chloroazaphosphatranes was reported more than thirty years ago by J. G. Verkade, the first synthesis of fluoroazaphosphatranes was only described in 2018 by Stephan et al. Currently, no common and versatile procedure exists to access fluoroazaphosphatranes platform with different structural characteristics. In this report, a new and simple synthesis of this class of compounds was developed based on the nucleophilic attack of the fluoride anion on chloroazaphosphatrane derivatives with good to high isolated yields for the corresponding fluoroazaphosphatranes (70–92%). The scope of the reaction was widened to fluoroazaphosphatranes bearing various substituents and X‐ray molecular structures of two of them are reported. The stability of fluoroazaphosphatranes toward nucleophilic solvents like water has been investigated. As they revealed much more robust cations than their chloroazaphosphatrane parents, their chloride salts were tested as organocatalysts for the formation of cyclic carbonates from epoxides and CO2. Fluoroazaphosphatranes proved to be both efficient and stable catalytic systems for CO2 conversion with catalytic activities similar to those of azaphosphatranes, and no decomposition of the cation was observed at the end of reaction. [ABSTRACT FROM AUTHOR]

The previous decade has witnessed a drastic increase of European incentives aimed at pushing forward the transition from an exclusively petro‐based economy toward a strong and homogeneous bio‐based economy. Since 2012, numerous programs have been developed to stimulate and promote research and innovation relying on sustainable and renewable resources. Terrestrial biomass is a virtually infinite reservoir of biomacromolecules, the biorefining of which provides platform molecules of low complexity yet with tremendous industrial potential. Among such bio‐based platform molecules, polyols and, more specifically, molecules featuring vicinal diols have gained tremendous interest and have stimulated an increasing research effort from the chemistry and chemical engineering communities. This Review revolves around the most promising process conditions and technologies reported since 2012 that specifically target bio‐based vicinal diols and promote their transformation into value‐added molecules of wide industrial interest, such as olefins, epoxides, cyclic carbonates, and ketals. [ABSTRACT FROM AUTHOR]

Supramolecular catalysis can provide distinct advantages for the catalytic conversion of CO2 into carbonates by cycloaddition to epoxides. For example, the absence of metals in the catalytic site, and the easy design for optimization. The incorporation of multiple functionalities in pseudopeptidic macrocycles with a pendant arm allows catalytic systems to be obtained where halide anions (nucleophilic activating agents for epoxides), hydrogen bond acceptor sites (activating agents for epoxides and stabilizing sites for anionic intermediates), and amine groups (Lewis basic sites for activating CO2) are in proximity. This allows a high activity in the cycloaddition of CO2 to styrene oxide under mild conditions (turnover number (TON) = 900, CO2 balloon, 100 °C, 5 h). The primary amino groups in the arm facilitate the immobilization of these macrocyclic structures in cross‐linked polymeric matrices containing ammonium halide fragments. Such multifunctional insoluble polymers afford excellent catalytic results with high TON and turnover frequency values and remarkable productivities (>10 gprod gresin−1 h−1). This activity is maintained for a variety of epoxides and is retained after several catalytic runs. Their performance is significantly higher than those reported for most heterogenous supramolecular catalytic systems for CO2 transformation into carbonates. [ABSTRACT FROM AUTHOR]

Rh(I)‐catalyzed decarboxylative arylation of alkynyl cyclic carbonates using commercially available and low‐toxic aryl boronic acids has been disclosed. Depending on the nature of the cyclic carbonates, the methodology provides a straightforward platform to access either substituted 2,3‐allenols or 1,3‐butadiene derivatives. Internal alkynyl cyclic carbonates undergo monoarylation to conveniently afford 2,3‐allenols with high syn‐selectivity for the aryl and hydroxy groups. Whereas, terminal alkynyl carbonates led to the formation of diarylated 1,3‐butadiene derivatives having cis‐configuration for the two aryl groups via allenyl rhodium(I)alkoxide intermediate. The compatibility of various functional groups allowed to develop a library of diversely functionalized scaffolds with excellent regioselectivity in good yields. Late‐stage transformation of a series of natural products highlights the wide applicability of the arylation process. Additionally, scale‐up experiments and downstream transformations of α‐allenol derivatives into other valuable heterocycles illustrate the efficacy of the protocol. [ABSTRACT FROM AUTHOR]

This work reports on the use of gallium aminotrisphenolate compounds as catalysts for the synthesis of cyclic carbonates from epoxides and CO2. The results show that they are highly active, and more so than the corresponding aluminium congeners. The catalyst system is applicable at low and elevated temperatures across a wide substrate scope including terminal, internal, multiple and fully deuterated epoxides. Applying low catalyst loadings has allowed for a TON of 344,000 to be obtained, highlighting their stability. A DFT investigation has confirmed that the gallium catalysts have lower energetic profiles compared to the aluminium congeners. Measurement of the Lewis acidity of both the gallium and aluminium aminotrisphenolate compounds using the Gutmann‐Beckett method provides the experimental proof that the gallium compounds are more Lewis acidic than their aluminium congeners. Finally, Ab‐Initio Molecular Dynamic (AIMD) simulations have investigated and quantified the dynamic behaviour of the catalytic systems, highlighting an important increase in fluxionality in some cases which helps to explain the increase in catalytic activity. [ABSTRACT FROM AUTHOR]

Chemical fixation of CO2 as C1 source at ambient temperature and low pressure is an energy‐saving way to make use of the green‐house gas, but it still remains a challenge since efficient catalyst with high catalytic active sites is required. Here, a novel monoclinic azo‐functionalized Zr‐based metal−organic polyhedron (Zr‐AZDA) has been prepared and applied in CO2 fixation with epoxides. The inherent azo groups not only endow Zr‐AZDA with good solubilization, but also act as basic sites to enrich CO2 showing efficient synergistic catalysis as confirmed by TPD‐CO2 analysis. XPS results demonstrate that the Zr active sites in Zr‐AZDA possess suitable Lewis acidity, which satisfies both substrates activation and products desorption. DFT calculation indicates the energy barrier of the rate‐determining step in CO2 cycloaddition could be reduced remarkably (by ca. 60.9 %) in the presence of Zr‐AZDA, which may rationalize the mild and efficient reaction condition employed (80 °C and 1 atm of CO2). The work provides an effective multi‐functional cooperative method for improvement of CO2 cycloaddition. [ABSTRACT FROM AUTHOR]

A series of dopamine‐based mono‐ and dinuclear boronate esters are studied as stable, efficient, and green metal‐free catalysts for coupling CO2 with epoxides under suitable and solvent‐free conditions. Under the optimized reaction conditions, dinuclear boronate esters compared with those with mononuclear compounds display high catalytic activity and selectivity for the chemical conversion of CO2 into cyclic organic carbonates as a valuable product. Ferrocene group containing boronate ester (B4a) display the highest activity for the carboxylation of epichlorohydrin at 100 °C and 1.6 MPa of CO2 pressure, obtaining 96.3% conversion after just 2 h. After seeing a high catalytic performance of trigonal‐planar boronate ester (B1–B5) and tetrahedral boronate ester (B1a–B5a) catalysts, the effect of ionic liquid, epoxide, base, temperature, CO2 pressure, reaction time, and amount of catalyst/substrate/cocatalyst is investigated for these catalysts. The newly synthesized dopamine‐based trigonal‐planar and tetrahedral boronate esters are entirely characterized by melting point, elemental analysis, NMR (1H, 13C, and 11B NMR) spectroscopy, FT‐IR spectroscopy, UV–vis spectroscopy, and LC–MS/MS spectrometry. [ABSTRACT FROM AUTHOR]

An operationally mild, ruthenium‐based photocatalytic protocol has been developed for the conversion of γ‐mono‐ and γ,γ‐disubstituted allyl carbonates in the presence of Umemoto's reagent to afford substituted six‐membered cyclic carbonates. Variation and diversification of the carbonate ring substitution provides access to new monomers useful in ring‐opening polymerization leading to polycarbonates with potentially tailored properties, as illustrated by comparative experiments using monomers with different pi‐stacking capabilities. [ABSTRACT FROM AUTHOR]

The development of an active and competent catalyst for the conversion of carbon dioxide (CO2) to value added‐chemicals at low pressure and temperature have great importance in the field of industrial chemical production as well as in tackling global warming. In this report, nitridated dendritic fibrous nano‐silica (N‐DFNS) as highly porous and stable nano‐material have been synthesized by using ammonolysis reaction at various temperature ranging from 500–800 °C and used as heterogeneous catalysts in combination with TBAI for the synthesis of cyclic carbonates from CO2 and epoxide. The presence of high surface area balanced acid‐base bi‐functionalities generated on silica due to ammonolysis offered high activity towards the synthesis of cyclic carbonates at the atmospheric pressure with excellent recyclability. [ABSTRACT FROM AUTHOR]

Metal‐Organic Frameworks (MOFs) have been used to catalyze the conversion of CO2 to cyclic carbonates through cycloaddition reaction. A series of MOFs composites based on Cu‐BTC (H3BTC, 1,3,5‐Benzenetricarboxylic acid) were screened out by adjusting the ligands and loaded materials. Among them, Cu‐BTC@ZnFe2O4 achieved good yields in this reaction, and after several catalytic cycles, the yield also remained above 90 %. The larger the steric hindrance of epoxides used, the lower the yields of cycloaddition reaction. In addition, computational chemistry was used to explain this catalytic process. After adding the catalyst, the energy barrier of the initial step of the reaction was effectively reduced. [ABSTRACT FROM AUTHOR]