Lewis acid-modulated interfaces for mild deuteration of alcohols with D2O

Sustainable deuteration of monohydric alcohols with D 2 O under mild conditions remains challenging because of the intrinsic inertness of aliphatic sp 3 C–H bonds. Herein, a Ru catalyst supported on Ni-doped MCM-41 was developed to construct Lewis acid-modulated metal-support interfaces for efficient heterogeneous hydrogen isotope exchange. Under mild conditions (40 ℃, 0.1 MPa H 2 ), the catalyst afforded up to 99% deuterium incorporation for 1-hexanol, whereas Ru/MCM-41 gave only ∼ 24%. The enhanced performance is attributed to the combined effects of high Ru dispersion and Ni-derived interfacial acidity. Spectroscopic results indicated that Ni-O-Si motifs electronically modified interfacial Ru sites. Mechanistic studies indicated that D 2 O is the dominant deuterium source under the present conditions and showed that deuteration proceeds through rapid hydroxyl exchange followed by rate-limiting C–H activation at the Ru-Lewis acid interface (k H /k D  = 2.22), consistent with a radical-mediated pathway. The catalyst also showed broad substrate scope and good durability, retaining > 90% deuterium incorporation after 14 cycles. These results identify Lewis acid-modulated metal-support interfaces as an effective motif for heterogeneous deuteration with D 2 O under mild conditions. Download: Download high-res image (67KB) Download: Download full-size image