Recyclable and efficient heterogenized Rh and Ir catalysts for the transfer hydrogenation of carbonyl compounds in aqueous medium

Abstract

Covalent-triazine-framework (CTF) based Ir/Rh catalysts for the aqueous-phase transfer hydrogenation of carbonyl compounds to alcohols using formate as the H2-source.

Carbon Nitride as a Ligand: Selective Hydrogenation of Terminal Alkenes Using [(η5‐C5Me5)IrCl(g‐C3N4‐κ2N,N’)]Cl

“…In addition, [Cp*IrCl] + has been incorporated as a cofactor in artificial metalloenzymes, exploiting the chiral enzyme environment for enantioselective transfer hydrogenation of imines . Furthermore, [Cp*IrCl] + has also been coordinated to frameworks based on covalent triazine, heptazine and phenanthroline and applied to transfer hydrogenation of ketones and direct hydrogenation of carbon dioxide to formate . We were motivated to explore g‐C 3 N 4 for hydrogen‐related catalysis because of the demonstrated photocatalytic proton/hydrogen reactivity of g‐C 3 N 4 that may potentially support thermal hydrogenation chemistry.…”

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

“…The immobilization of homogeneous catalysts also allows insoluble catalysts, which would otherwise be aggregated, to be well dispersed in the reaction medium such as water, resulting in the significant enhancement in the catalytic activity. The use of water as solvent with immobilized catalysts also call attention to the importance of the requirements of green chemistry . In general, the supported catalyst may be more sterically hindered and hence less accessible to substrates as compared to its non‐supported counterpart, while the selectivity may be enhanced by the steric effect.…”

“…In general, the supported catalyst may be more sterically hindered and hence less accessible to substrates as compared to its non‐supported counterpart, while the selectivity may be enhanced by the steric effect. Catalyst instability in the homogeneous phase is mainly caused by bimolecular deactivation pathways, which are prevented by immobilization of the catalyst to isolate the catalyst reactive sites …”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The immobilization of homogeneous catalysts also allows insoluble catalysts, which would otherwise be aggregated, to be well dispersed in the reaction medium such as water, resultingi nt he significant enhancement in the catalytic activity.T he use of water as solvent with immobilizedc atalysts also call attentiont ot he importance of the requirements of green chemistry. [21][22][23][24][25][26] In general,t he supported catalyst may be more sterically hindered and hence less accessible to substrates as compared to its non-supported counterpart,w hile the selectivity may be enhanced by the steric effect. Catalysti nstability in the homogeneousp hase is mainly caused by bimolecular deactivation pathways, whicha re prevented by immobilization of the catalyst to isolate the catalystreactive sites.…”

Surface Modification of a MOF-based Catalyst with Lewis Metal Salts for Improved Catalytic Activity in the Fixation of CO2 into Polymers

“…However, heterogeneous catalysts are preferred for industrial scale applications owing to their low cost, easy synthesis, facile separation from products, and reusability [28][29][30][31]. Among the heterogeneous catalysts, zinc dicarboxylates, Zn-Co double metal cyanide complexes, and ternary rare-earth complexes are found to be particularly active for the copolymerization of CO 2 and epoxides.…”