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A Reusable CNT‐Supported Single‐Atom Iron Catalyst for the Highly Efficient Synthesis of C−N Bonds
Author(s) -
Ding Qifeng,
Yu Yang,
Huang Fei,
Zhang Lihui,
Zheng JianGuo,
Xu Mingjie,
Baell Jonathan B.,
Huang He
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201905468
Subject(s) - catalysis , carbon nanotube , chemistry , metal , atom (system on chip) , chemical engineering , materials science , nanotechnology , organic chemistry , computer science , engineering , embedded system
C−N bond formation is regarded as a very useful and fundamental reaction for the synthesis of nitrogen‐containing molecules in both organic and pharmaceutical chemistry. Noble‐metal and homogeneous catalysts have frequently been used for C−N bond formation, however, these catalysts have a number of disadvantages, such as high cost, toxicity, and low atom economy. In this work, a low‐toxic and cheap iron complex (iron ethylene‐1,2‐diamine) has been loaded onto carbon nanotubes (CNTs) to prepare a heterogeneous single‐atom catalyst (SAC) named Fe‐N x /CNTs. We employed this SAC in the synthesis of C−N bonds for the first time. It was found that Fe‐N x /CNTs is an efficient catalyst for the synthesis of C−N bonds starting from aromatic amines and ketones. Its catalytic performance was excellent, giving yields of up to 96 %, six‐fold higher than the yields obtained with noble‐metal catalysts, such as AuCl 3 /CNTs and RhCl 3 /CNTs. The catalyst showed efficacy in the reactions of thirteen aromatic amine substrates, without the need for additives, and seventeen enaminones were obtained. High‐angle annular dark‐field scanning transmission electron microscopy in combination with X‐ray absorption spectroscopy revealed that the iron species were well dispersed in the Fe‐N x /CNTs catalyst as single atoms and that Fe‐N x might be the catalytic active species. This Fe‐N x /CNTs catalyst has potential industrial applications as it could be cycled seven times without any significant loss of activity.