2023/05/17 by Sanjeev Kushwaha, Mahendra Kumar Awasthi, A. Das +3 · 1 citation
Chemical Engineering · Chemistry · Energy · #Carbon dioxide utilization in catalysis #Asymmetric Hydrogenation and Catalysis #CO2 Reduction Techniques and Catalysts
paper · doi:10.1021/acs.inorgchem.2c04079
Diruthenium complexes [(η 6 -arene)RuCl 2 (μ-κ 2:κ 2 -benztetraimd)] 2+ containing the bridging bis-imidazole methane-based ligand 1,4-bis(bis(2-ethyl-5-methyl-1 H -imidazol-4-yl)methyl)benzene (benztetraimd) are synthesized for catalytic formic acid dehydrogenation in water at 90 °C. Catalyst [(η 6 - p -cymene)RuCl 2 (μ-κ 2:κ 2 -benztetraimd)] 2+ [1-Cl 2 ] exhibited a remarkably high turnover frequency (1993 h –1 per Ru atom) and long-term stability over 60 days for formic acid dehydrogenation, while the analogous (η 6 -benzene)diruthenium and mononuclear catalysts displayed low activity with poor long-term stability. Notably, catalyst [1-Cl 2 ] also displayed an appreciably high turnover number of 93 200 for the bulk-scale reaction. In addition, the in-depth mass and nuclear magnetic resonance investigations under the catalytic and control experimental conditions revealed the active involvement of several crucial catalytic intermediate species, such as Ru–aqua species [(η 6 - p -cymene)Ru(H 2 O) 2 (μ-L)] 2+ [1-(OH 2 ) 2 ], Ru–formato species [(η 6 - p -cymene)Ru(HCOO) 2 (μ-L)] [1 - (HCOO) 2 ], and Ru–hydrido species [(η 6 - p -cymene)Ru(H) 2 (μ-L)] [1-(H) 2 ], in the catalytic formic acid dehydrogenation reaction.