Rhenium Complexes of Tridentate PNP Ligands: Efficient Catalysts for the Hydrogenation of Ketones and Aldehydes

NH(CH 2 CH 2 PPh 2 ) 2 Re(CO) 2 Cl, a complex bearing diphenylphosphino groups, were prepared and demonstrated markedly superior catalytic activity in hydrogenation of ketones and aldehydes to the respective alcohols compared to its counterparts NH(CH 2 CH 2 PCy 2 ) 2 Re(CO) 2 Cl and NH(CH 2 CH 2 P i Pr 2 ) 2 Re(CO) 2 Cl. This complex proceeds the hydrogenation via a Re‐H/N‐H cooperative reaction mechanism, realizing a turnover frequency of up to 4008 h −1 and an exceptional turnover number of 51,600.