Cyclometallated Ruthenium Complexes for Transfer Hydrogenation and Hydrogenation Reactions

The catalytic hydrogenation and transfer hydrogenation of carbonyl compounds to alcohols is a reaction of broad application in the industry, resulting in a lower environmental impact and an easier work-up with respect to the classical approach with NaBH4, LiAlH4 and Al alkoxides.1 The search of well-designed and productive catalysts of ruthenium, which is cheaper with respect to rhodium and iridium, has led to a number of efficient hydrogenation systems. We report here the isolation of highly active ruthenium cyclometallated CNN and PC catalysts containing the ampy motif2 with phosphine and CO ligands, starting from phosphine and carbonyl Ru precursors. The presence of a metal-carbon σ-bond leads to robust and productive catalysts for the reduction of commercial-grade aldehydes and (bulky) ketones using H2 (5-30 atm), 2-propanol or ammonium formate,3 with S/C up to 100000 and TOF up to 100000 h-1. Acknowledgements We gratefully acknowledge the financial support from MIUR (PRIN 2015, n° 20154X9ATP_005) References 1. (a) Xie, X.; Lu, B.; Li, W.; Zhang, Z. Coord. Chem. Rev. 2018, 355, 39. (b) Wang, D.; Astruc, D. Chem. Rev. 2015, 115, 6621. 2 Chelucci, G.; Baldino, S.; Baratta, W. Coord. Chem. Rev. 2015, 300, 29. 3 Baldino, S.; Facchetti, S.; Nedden, H. G.; Zanotti-Gerosa, A.; Baratta, W. ChemCatChem, 2016, 8, 3195.