Biomass-Derived Single Zn Atom Catalysts: The Multiple Roles of Single Zn Atoms in the Oxidative Cleavage of C-N Bonds.

The C-N bond cleavage represents one kind of important organic and biochemical transformation, which has attracted great interest in recent years. The oxidative cleavage of C-N bonds in N , N -dialkylamines into N -alkylamines has been well documented, but it is challenging in the further oxidative cleavage of C-N bonds in N -alkylamines into primary amines due to the thermally unfavorable release of α-position H from N-C α -H and the paralleling side reactions. Herein, a biomass-derived single Zn atom catalyst (ZnN 4 -SAC) was discovered to be a robust heterogeneous non-noble catalyst for the oxidative cleavage of C-N bonds in N -alkylamines with O 2 molecules. Experimental results and DFT calculation revealed that ZnN 4 -SAC not only activates O 2 to generate superoxide radicals (·O 2 - ) for the oxidation of N -alkylamines to generate imine intermediates (C=N), but the single Zn atoms also served as the Lewis acid sites to promote the cleavage of C=N bonds in imine intermediates, including the first addition of H 2 O to generate α-hydroxylamine intermediates and the following C-N bond cleavage via a H atom transfer process.