A DFT Study on the Mechanism of the Coupling Reaction between Chloromethyloxirane and Carbon Dioxide Catalyzed by Re(CO)5Br

Unravelling the Mechanism of CO2 Activation: Insights Into Metal-Metal Cooperativity and Spin-Orbit Coupling with {3d-4f} Catalysts

Converting CO2 into useful chemicals using metal catalysts is a significant challenge in chemistry. Among the various catalysts reported, transition metal lanthanide hybrid {3d-4f} complexes stand out for their superior efficiency and site selectivity. However, unlike transition metal catalysts, understanding the origin of this efficiency in lanthanides poses a challenge due to their orbital degeneracy, rendering the application of DFT methods ineffective. In this study, we employed a combination of density functional theory (DFT) and ab initio CASSCF/RASSI-SO calculations to explore the mechanism of CO2 conversion to cyclic carbonate using a 3d-4f heterometallic catalyst for the first time. This work unveils the importance of 3d and 4f metal cooperativity and the role of individual spin-orbit states in dictating the overall efficiency of the catalyst.

Cycloaddition mechanisms of CO2 and epoxide catalyzed by salophen – an organocatalyst free from metals and halides

The coupling mechanism of CO₂ and epichlorohydrin catalyzed by salophen is computed. A neutral concerted bifunctional mechanism of phenolate as nucleophile and phenol as H-bonding donor in epoxide ring-opening and CO₂ addition is suggested.

Mechanistic guidelines in nonreductive conversion of CO2: the case of cyclic carbonates

This perspective provides general mechanistic guidelines for the catalytic formation of cyclic organic carbonates from CO₂ and cyclic ethers.

Synthesis of 2-Nickela(II)oxetanes from Nickel(0) and Epoxides: Structure, Reactivity, and a New Mechanism of Formation

2-Nickelaoxetanes have been frequently invoked as reactive intermediates in catalytic reactions of epoxides using nickel, but have never been isolated or experimentally observed in these transformations. Herein, we report the preparation of a series of well-defined nickelaoxetanes formed via the oxidative addition of nickel(0) with epoxides featuring ketones. The stereochemistry of the products is retained, which has not yet been reported for nickelaoxetanes. Theoretical calculations support a bimetallic ring-opening/closing pathway over a concerted oxidative addition. Initial reactivity studies of a nickelaoxetane demonstrated protonolysis, oxidatively induced reductive elimination, deoxygenation, and elimination reactions when treated with the appropriate reagents.

Surprisingly facile CO2 insertion into cobalt alkoxide bonds: A theoretical investigation

Exploiting carbon dioxide as co-monomer with epoxides in the production of polycarbonates is economically highly attractive. More effective catalysts for this reaction are intensively being sought. To promote better understanding of the catalytic pathways, this study uses density functional theory calculations to elucidate the reaction step of CO2 insertion into cobalt(III)-alkoxide bonds, which is also the central step of metal catalysed carboxylation reactions. It was found that CO2 insertion into the cobalt(III)-alkoxide bond of [(2-hydroxyethoxy)Co(III)(salen)(L)] complexes (salen = N,N"-bis(salicyliden-1,6-diaminophenyl)) is exothermic, whereby the exothermicity depends on the trans-ligand L. The more electron-donating this ligand is, the more exothermic the insertion step is. Interestingly, we found that the activation barrier decreases with increasing exothermicity of the CO2 insertion. Hereby, a linear Brønsted-Evans-Polanyi relationship was found between the activation energy and the reaction energy.

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.