Hf-MOF catalyzed Meerwein-Ponndorf-Verley (MPV) reduction reaction: Insight into reaction mechanism

Hf-MOF-808 exhibits excellent activity and specific selectivity on the hydrogenation of carbonyl compounds via a hydrogen transfer strategy. Its superior activity than other Hf-MOFs is attributed to its poor crystallinity, defects and large specific surface area, thereby containing more Lewis acid-base sites which promote this reaction. Density functional theory (DFT) computations are performed to explore the catalytic mechanism. The results indicate that alcohol and ketone fill the defects of Hf-MOF to form a six-membered ring transition state (TS) complex, in which Hf as the center of Lewis stearic acid coordinates with the oxygen of the substrate molecule, thus effectively promoting hydrogen transfer process. Other reactive groups, such as ?NO2, C = C, -CN, of inadequate hardness or large steric hindrance are difficult to coordinate with Hf, thus weakening their catalytic effect, which explains the specific selectivity Hf-MOF-808 for reducing the carbonyl group.

Automated summary

Hf-MOF-808 shows excellent activity and specific selectivity in the hydrogenation of carbonyl compounds due to its poor crystallinity, defects, and large specific surface area, providing more Lewis acid-base sites to promote the reaction. Using DFT computations, it was found that the defects of Hf-MOF play a crucial role in promoting the hydrogen transfer process, leading to its specific selectivity for reducing carbonyl groups.