Aliphatic Mn–PNP complexes for the CO2 hydrogenation reaction: a base free mechanism. Issue 15 (9th June 2017)

• Record Type: Journal Article
• Authors: Rawat, Kuber Singh; Pathak, Biswarup
• Is Part Of: Catalysis science & technology. Volume 7:Issue 15(2017)
• Page Start: 3234
• Page End: 3242
• Publication Date: 2017-06-09
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c7cy00737j
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Aliphatic amido Mn–PNP-based complexes were found to be promising for CO2 hydrogenation reaction. Abstract : Using density functional theory (DFT) calculations, a series of aliphatic amido Mn–PNP-based complexes was studied for base free CO2 hydrogenation. The amido group present in the aliphatic PNP ligand favours a heterolytic H2 cleavage and proton transfer mechanism contrary to any active catalyst for CO2 hydrogenation, where base facilitates this process. Further, a set of σ-donor (PH3 and PMe3 ) and π-acceptor (CO and PF3 ) ligand-based Mn–PNP complexes was studied to understand the electronic and steric effects on the rate determining steps. Our reaction free-energy profile suggests thatMn1 is a promising base-free catalyst for CO2 hydrogenation with an overall free energy barrier of 23.3 kcal mol −1 . We found that the proper combination of σ-donor and π-acceptor ligands may not be a necessary criteria to improve the overall activity of the catalyst although π-acceptor ligands favour heterolytic H2 -cleavege and σ-donor ligands favour the hydride transfer mechanism.