Qin Jingzhong, Han Bo, Lu Xiaomei, Nie Jiabao, Xian Chensheng, Zhang Zehui
School of Chemistry and Materials Science, South-Central Minzu University, Wuhan, Hubei 430074, P. R. China.
Sustainable Energy Laboratory, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, Hubei 430074, P. R. China.
JACS Au. 2023 Feb 16;3(3):801-812. doi: 10.1021/jacsau.2c00605. eCollection 2023 Mar 27.
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 ,-dialkylamines into -alkylamines has been well documented, but it is challenging in the further oxidative cleavage of C-N bonds in -alkylamines into primary amines due to the thermally unfavorable release of α-position H from N-C-H and the paralleling side reactions. Herein, a biomass-derived single Zn atom catalyst (ZnN-SAC) was discovered to be a robust heterogeneous non-noble catalyst for the oxidative cleavage of C-N bonds in -alkylamines with O molecules. Experimental results and DFT calculation revealed that ZnN-SAC not only activates O to generate superoxide radicals (·O ) for the oxidation of -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 HO to generate α-hydroxylamine intermediates and the following C-N bond cleavage via a H atom transfer process.
C-N键的断裂是一种重要的有机和生物化学转化反应，近年来备受关注。将β,γ-二烷基胺中的C-N键氧化断裂为β-烷基胺的反应已有充分报道，但由于从N-C-H的α位热不利地释放H以及平行的副反应，将β-烷基胺中的C-N键进一步氧化断裂为伯胺具有挑战性。在此，发现一种生物质衍生的单锌原子催化剂（ZnN-SAC）是一种用于β-烷基胺与O分子进行C-N键氧化断裂的稳健非均相非贵金属催化剂。实验结果和DFT计算表明，ZnN-SAC不仅能活化O生成超氧自由基（·O₂⁻）以氧化β-烷基胺生成亚胺中间体（C=N），而且单锌原子还作为路易斯酸位点促进亚胺中间体中C=N键的断裂，包括首先添加HO生成α-羟胺中间体以及随后通过氢原子转移过程进行的C-N键断裂。
