Dataset for: "Does the configuration at metal matter in Noyori-Ikariya type asymmetric transfer hydrogenation catalysts?"

Noyori-Ikariya type [(arene)RuCl(TsDPEN)] complexes are widely used C=O and C=N reduction catalysts which produce chiral alcohols and amines via a key ruthenium-hydride intermediate that determines the stereochemistry of the product. Whereas many details about the interactions of the pro-chiral substrate with the hydride complex, and the nature of the hydrogen transfer from the latter to the former have been investigated over the past 25 years, the role of the stereochemical configuration at the stereogenic ruthenium centre in the catalysis has not been elucidated so far. Using operando FlowNMR spectroscopy and Nuclear Overhauser Effect spectroscopy we show the existence of two diastereomeric hydride complexes under reaction conditions, assign their absolute configurations in solution, and monitor their interconversion during transfer hydrogenation catalysis. Configurational analysis and multi-functional DFT calculations show the λ-(R,R)S configured [(mesitylene)RuH(TsDPEN)] complex to be both thermodynamically and kinetically favoured over its λ-(R,R)R isomer with the opposite configuration at ruthenium. Computational analysis of both diastereomeric catalytic manifolds show the major λ-(R,R)S configured [(mesitylene)RuH(TsDPEN)] complex to dominate asymmetric ketone reduction catalysis, with the minor λ-(R,R)R [(mesitylene)RuH(TsDPEN)] stereoisomer being both less active and less enantioselective. These findings also hold true for a tethered catalyst derivative with a propyl linker between the arene and TsDPEN ligands, and thus show enantioselective transfer hydrogenation catalysis with Noyori-Ikariya complexes to proceed via a lock-and-key mechanism.