??????????????Integration of Metal Catalysis and Organocatalysis in a Metal Nanocluster with Anchored Proline

Chiral metal nanoclusters have recently been attracting great attention. It is challenging to realize asymmetric catalysis via atomically precise metal nanoclusters. Herein, we report the synthesis and total structure determination of chiral clusters [Au7Ag8(dppf)(3)(L-/D-proline)(6)]-(BF4)(2)(L-/D-Au7Ag8). Superatomic clusters L-/D-Au(7)Ag(8 )display intense and mirror-image Cotton effects in their CD spectra. Density functional theory (DFT) calculations were carried out to understand the correlation between electronic structures and the optical activity of the enantiomeric pair. Surprisingly, the incorporation of proline in a metal nanocluster can significantly promote the catalytic efficiency in asymmetric Aldol reactions. The increase of catalytic activity of Au(7)Ag(8 )in comparison with organocatalysis by proline is attributed to the cooperative effect of the metal core and prolines, showing the advantages of the integration of metal catalysis and organocatalysis in a metal nanocluster.

Automated summary

This article reports the synthesis and structure determination of chiral metal nanoclusters and investigates their potential in asymmetric catalysis. The incorporation of proline in the nanoclusters significantly enhances the catalytic efficiency in asymmetric reactions. This study demonstrates the promising application of metal nanoclusters in chiral catalysis.