A DFT Study on the Mechanism of the Cycloaddition Reaction of CO2to Epoxides Catalyzed by Zn(Salphen) Complexes

Three powerful dinuclear metal–organic catalysts for converting CO2 into organic carbonates

Hydroxyl/amino-functionalized dinuclear metal catalysts show high catalytic activity for the synthesis of cyclic carbonates from CO₂ and epoxides under mild conditions.

Iron amino-bis(phenolate) complexes for the formation of organic carbonates from CO2 and oxiranes

Air-stable iron complexes display good activity for CO₂-epoxide cycloadditions and reactivity trends across family are reported.

Catalytic performance of a series of guanidinium-based ionic liquids in the coupling reaction of carbon dioxide with epoxides

The cycloaddition reaction of CO₂ into EO, catalyzed by a series of functional guanidinium-based ionic liquids, is schematically studied by the DFT.

Recent application of calculations of metal complexes based on density functional theory

Recent application of density functional theory (DFT) for metal complexes is reviewed to show the achievements of DFT and the challenges for it, as well as the methods for selecting proper functionals.

Experimental and theoretical insights into binary Zn-SBA-15/KI catalysts for the selective coupling of CO2and epoxides into cyclic carbonates under mild conditions

Experimental and theoretical evidence gives insights into Zn-SBA-15/KI for selective coupling of CO₂and epoxides under mild conditions.

Quaternary ammonium-based ionic liquids bearing different numbers of hydroxyl groups as highly efficient catalysts for the fixation of CO2: a theoretical study by QM and MD

The mechanism of coupling reactions of CO₂ with PO catalyzed by NEt_n(HE)_4−nBr (n = 1–4) by QM and MM.

Design, synthesis and characterization of novel dioxime ligand-based cobaloxime compounds for application in the coupling of CO2 with epoxides

Novel dioxime-based cobaloxime complexes have been obtained by click chemistry and used as catalysts for the conversion of CO₂ to a cyclic carbonate without using any solvent.

Titanate nanotube-promoted chemical fixation of carbon dioxide to cyclic carbonate: a combined experimental and computational study

Titanate nanotubes are efficiently used as air- and water-tolerant, and recyclable Lewis acid catalysts for CO₂ fixation to cyclic carbonate.

Lewis acid–base bifunctional aluminum–salen catalysts: synthesis of cyclic carbonates from carbon dioxide and epoxides

Two Lewis acid–base bifunctional Al(salen) complexes proved to be efficient and recyclable one-component catalysts for CO₂ fixation.

Highly Efficient Organocatalyzed Conversion of Oxiranes and CO2 into Organic Carbonates

A binary catalyst system based on tannic acid/NBu4X (X=Br, I) is presented as a highly efficient organocatalyst at very low catalyst loading for the coupling of carbon dioxide and functional oxiranes to afford organic carbonates in good yields. The presence of multiple polyphenol fragments within the tannic acid structure is considered to be beneficial for synergistic effects that lead to higher stabilization of the catalyst structure during catalysis. The observed turnover frequencies (TOFs) exceed 200 h(-1) and are among the highest reported to date for organocatalysts in this area of CO2 conversion. This organocatalyst system presents a useful, readily available, inexpensive, and, above all, reactive alternative for most of the metal-based catalyst systems reported to date.

Intermolecular proton transfer in cyclic carbonate synthesis from epoxide and carbon dioxide catalyzed by azaphosphatranes: a DFT mechanistic study

The activity of azaphosphatranes, novel types of non-metal and solvent-free catalysts for the synthesis of cyclic carbonates from epoxides and CO₂, is unraveled by DFT calculations.

Quaternary ammonium hydroxide as a metal-free and halogen-free catalyst for the synthesis of cyclic carbonates from epoxides and carbon dioxide

Tetrabutylammonium hydroxide (TBAH) acted as a good catalyst for the formation of cyclic carbonates from epoxides and CO₂ under solvent-free conditions.

Metal complexes bearing 2-(imidazol-2-yl)phenol ligands: synthesis, characterization and catalytic performance in the fixation of carbon dioxide with epoxides

A series of metal complexes bearing 2-(imidazol-2-yl)phenol ligands were synthesized and proven to be efficient catalysts for the fixation of CO₂.

A polyhedral oligomeric silsesquioxane-based catalyst for the efficient synthesis of cyclic carbonates

Polyhedral oligomeric silsesquioxane functionalized with imidazolium chloride peripheries was synthesized and successfully used as a catalyst for CO₂ conversion.

Mechanism of fixation of CO2 with an epoxide catalyzed by ZnBr2 and a choline chloride co-catalyst: a DFT study

The cycloaddition mechanism of the reaction of propylene oxide with CO₂ catalyzed by ZnBr₂/choline chloride is elucidated using a DFT method.

Kinetics of the (salen)Cr(iii)- and (salen)Co(iii)-catalyzed copolymerization of epoxides with CO2, and of the accompanying degradation reactions

The catalytic cycle of the (salen)M(iii)-catalyzed copolymerization for a variety of epoxides with CO₂ is elucidated using computational chemistry, and factors that control the kinetics and product distribution of these reactions are described.

Silanediol-catalyzed carbon dioxide fixation

Carbon dioxide is an abundant and renewable C1 source. However, mild transformations with carbon dioxide at atmospheric pressure are difficult to accomplish. Silanediols have been discovered to operate as effective hydrogen-bond donor organocatalysts for the atom-efficient conversion of epoxides to cyclic carbonates under environmentally friendly conditions. The reaction system is tolerant of a variety of epoxides and the desired cyclic carbonates are isolated in excellent yields.

Carbon dioxide as a protecting group: highly efficient and selective catalytic access to cyclic cis-diol scaffolds

The efficient and highly selective formation of a wide range of (hetero)cyclic cis-diol scaffolds using aminotriphenolate-based metal catalysts is reported. The key intermediates are cyclic carbonates, which are obtained in high yield and with high levels of diastereo- and chemoselectivity from the parent oxirane precursors and carbon dioxide. Deprotection of the carbonate structures affords synthetically useful cis-diol scaffolds with different ring sizes that incorporate various functional groups. This atom-efficient method allows the simple construction of diol synthons using inexpensive and accessible precursors and green metal catalysts and showcases the use of CO2 as a temporary protecting group.

Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO₂. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu₄I and a bifunctional system Zn(salpyr)·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism.

Reaction mechanism of epoxide cycloaddition to CO₂ catalyzed by salen-M (M = Co, Al, Zn)

We propose a catalytic mechanism for the cycloaddition of epoxide to carbon dioxide catalyzed by salen-M (M = Co, Zn, Al) based on density functional theory calculations. The catalytic reaction follows a single-site mechanism rather than a bimetallic-site mechanism, which includes four steps: epoxide adsorption by salen-M, ring opening of epoxide, CO2 insertion, and intramolecular rearrangement. Our calculation results showed that the highest reaction barrier for salen-Co catalyst is only 9.94 kcal/mol, which is lower than that of salen-Al (14.38 kcal/mol) and salen-Zn (13.05 kcal/mol). The results indicate that the reaction catalyzed by salen-Al, salen-Co, or salen-Zn can occur at room temperature and atmospheric pressure, which is in agreement with experimental results. The mechanism can be used for the design of a novel catalyst for this reaction.

A concise review of computational studies of the carbon dioxide–epoxide copolymerization reactions

The production of polycarbonates from carbon dioxide and epoxides is an important route by which waste CO₂ is converted into useful products. This review surveys the use of computational chemistry toward understanding this reaction.

‘Ring-expansion addition’ of epoxides using applied potential: an investigation of catalysts for atmospheric pressure carbon dioxide utilization

An investigation of catalysts for atmospheric pressure carbon dioxide insertion into epoxides under electrosynthetic conditions is reported. Careful selection of electrode materials, enabled a catalyst free system to be developed.