Coupling reaction of carbon dioxide and epoxides efficiently catalyzed by one-component aluminum–salen complex under solvent-free conditions

Diamine-modified porous indium frameworks with crystalline porous materials (CPM)-5 structure for carbon dioxide fixation under co-catalyst and solvent free conditions

In the present work, functional diamine groups into indium frameworks to synthesize cyclic carbonates from CO₂ and epoxides with efficient catalytic activity in the absence of co-catalyst and solvent are reported for the first time. Crystalline porous materials (CPM)-5 modified with 1,2-phenylene diamine and ethylene diamine (CPM-5-PhDA and CPM-5-EDA), were prepared using a post-synthetic modification (PSM) method. The properties of the modified CPM-5 were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), N₂-adsorption, scanning electron microscopy (SEM), CO₂ adsorption, and temperature programmed desorption TPD methods. The presence of diamine groups as basic sites and indium Lewis acid sites in the framework structure were desirable for high catalytic activity. For a given catalyst weight, CPM-5-PhDA was the best candidate to appear with great catalytic activity and selectivity for the cycloaddition reaction at 100°C and 1 MPa CO₂ under co-catalyst and solvent free conditions. CPM-5-PhDA also was found to afford large and bulky epoxides. The catalyst can be easily separated and reused five times without any decline in activity.

Syntheses, Characterization, and Application of Tridentate Phenoxyimino-Phenoxy Aluminum Complexes for the Coupling of Terminal Epoxide with CO2: From Binary System to Single Component Catalyst

A series of binuclear aluminum complexes 1–3 supported by tridentate phenoxyimino-phenoxy ligands was synthesized and used as catalysts for the coupling reaction of terminal epoxide with carbon dioxide. The aluminum complex 1, which is catalytically inactive toward the coupling of epoxide with CO2 by itself, shows moderate activity in the presence of excess nucleophiles or organic bases at high temperature. In sharp contrast to complex 1, bifunctional complexes 2 and 3, which incorporate tertiary amine groups as the built-in nucleophile, are able to efficiently transform terminal epoxide with CO2 to corresponding cyclic carbonates as a sole product by themselves at 100 °C. The number of amine groups on the ligand skeleton and the reaction temperature exert a great influence on the catalytic activity. The bifunctional complexes 2 and 3 are also active at low carbon dioxide pressure such as 2 atm or atmospheric CO2 pressure. Kinetic studies of the coupling reactions of chloropropylene oxide/CO2 and styrene oxide/CO2 using bifunctional catalysts under atmospheric pressure of CO2 demonstrate that the coupling reaction has a first-order dependence on the concentration of the epoxide.

Chemical fixation of CO2 into cyclic carbonates catalyzed by bimetal mixed MOFs: the role of the interaction between Co and Zn

Catalytic conversion of carbon dioxide into cyclic carbonates in the presence of bimetal mixed MOFs.

New Coordination Complexes Based on the 2,6-bis[1-(Phenylimino)ethyl] Pyridine Ligand: Effective Catalysts for the Synthesis of Propylene Carbonates from Carbon Dioxide and Epoxides

We aimed to develop new effective catalysts for the synthesis of propylene carbonate from propylene oxide and carbon dioxide. A kind of M^x+LCl_x coordination complex was fabricated based on the chelating tridentate ligand 2,6-bis[1-(phenylimino)ethyl] pyridine (L). The obtained products were characterized by elemental analysis, infrared spectroscopy, ultraviolet spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. It was found that the catalytic activity of the complexes with different metal ions, the same ligand differed and co-catalyst, where the order of greatest to least catalytic activity was 2 > 3 > 1. The catalytic system composed of complex 2 and DMAP proved to have the better catalytic performance. The yields for complex 2 systems was 86.7% under the reaction conditions of 100 °C, 2.5 MPa, and 4 h. The TOF was 1026 h⁻¹ under the reaction conditions of 200 °C, 2.5 MPa, and 1 h. We also explored the influence of time, pressure, temperature, and reaction substrate concentration on the catalytic reactions. A hypothetical catalytic reaction mechanism is proposed based on density functional theory (DFT) calculations and the catalytic reaction results.

Conversion of CO2 into cyclic carbonates by a Co(ii) metal–organic framework and the improvement of catalytic activity via nanocrystallization

Nanocrystallization of MOFs provides a strategy for efficiently applying MOFs as catalysts towards CO₂ conversion and other MOF-catalyzed processes.

Development of pyridine based o-aminophenolate zinc complexes as structurally tunable catalysts for CO2 fixation into cyclic carbonates

Structure–reactivity correlation in o-aminophenolate zinc catalysts provides an atom-efficient protocol for the conversion of CO₂ into valuable cyclic carbonates.

Aluminium salabza complexes for fixation of CO2 to organic carbonates

A highly stable and easy to synthesize aluminium complex bearing a flexible N₂O₂-donor salabza ligand (N,N′-bis(salicylene)-2-aminobenzylamine) in combination with tetrabutylammonium bromide forms an active binary catalytic system for the cycloaddition of CO₂ to epoxides (TOFs 120–3434 h⁻¹) under mild conditions (10 bar, 80 °C) and low catalyst loadings (0.05–0.2 mol%).

Zn-based ionic liquids as highly efficient catalysts for chemical fixation of carbon dioxide to epoxides

Novel Zn-TSILs catalysts were developed, which showed high activity towards the cycloaddition of CO₂ to epoxides due to synergetic effects.

Organoantimony and organobismuth complexes for CO2fixation

The utilization of organoantimony and organobismuth complexes in CO₂fixation is reviewed in this article.