CO₂ Fixation by Dimeric Tb(III) Complexes: Synthesis, Structure, and Magnetism

Abstract

Two dinuclear complexes, [Tb2(L1)2(piv)2(NO3)2]·H2O (1) and [Tb2(L2)2(CF3CO2)2(H2O)4].2NO3 (2), have been prepared and characterized by single-crystal X-ray diffraction, where each metal ion is doubly phenoxido-bridged by the two phenolato oxygen atoms of the tetradentate Schiff-base ligand. Previous magnetic studies of 1 show that it is not a single-molecule magnet (SMM), while AC magnetic measurements of 2 show that it relaxes quite fast with μSQUID measurements revealing the presence of an interaction operating between the Tb ions. Through DC, μSQUID, and CASSCF calculations, the strength of the interaction in 2 can be quantified, which is of dipolar origin. Both complexes showed efficient catalytic activity toward the carbon dioxide insertion reaction into epoxides for the formation of organic cyclic carbonates. Catalytic synthesis of organic cyclic carbonates smoothly occurred at 60 °C under1 bar carbon dioxide pressure and neat conditions. Exocyclic as well as endocyclic epoxides produced a respective cyclic carbonate product with moderate to high yield (43–100%). Moreover, a high turnover number (7300–10000) along with a high turnover frequency (537.5–5000 h–1) are found in this catalytic reaction.

Utility of silver nanoparticles embedded on a covalent organic framework as a highly active catalyst for carboxylative cyclization with CO2: a sustainable route for production of tetronic acids and oxazolidinones

“…In the last few decades, several homogeneous and heterogeneous catalysts such as organocatalysts, alkali metalbased catalysts, transitions metal-based catalysts, and ionic liquid catalysts have been developed to serve this purpose. [11][12][13][14][15][16][17][18][19][20][21] Homogeneous catalysts, such as metal complexes and organocatalysts, have been shown to enhance the reaction efficiency and selectivity for CO 2 fixation reactions. However, heterogeneous catalysts offer several advantages over homogeneous catalysts in chemical reactions.…”

Experimental and Theoretical Investigation of Interfacial Engineering in Fe2O3/NiFe2O4 Heterostructures toward the Cycloaddition of CO2 with Styrene Oxide

“…Although the CO 2 capture and storage technology can reduce the CO 2 concentration in the atmosphere, the chemical utilization of CO 2 as a molecular C 1 synthon for the production of value-added chemicals is more appealing for achieving the goal of carbon neutrality and sustainable carbon recycling. − Several strategies have been proposed for the effective conversion of CO 2 , such as electrochemical CO 2 reduction, photocatalytic CO 2 transformation, catalytic hydrogenation of CO 2 , biochemical conversion of CO 2 , CO 2 reductive amination, and cycloaddition of CO 2 with epoxides. − Among the promising routes in CO 2 catalysis, the chemical fixation of CO 2 into epoxides for the synthesis of cyclic carbonates with a 100% atom efficiency is a vibrant research area. Cyclic carbonates, such as ethylene carbonate, propylene carbonate, and SC, are important aprotic solvents, electrolytes for lithium batteries, polymer precursors, and organic building blocks. − For example, SC can be generated by the cycloaddition reaction between CO 2 and SO via the ring-opening of SO, insertion of CO 2 , and intramolecular cyclization . In 1967, the synthesis of cyclic carbonates via the cycloaddition reaction was realized .…”