Mixed‐Valence Single‐Atom Catalyst Derived from Functionalized Graphene |
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Authors: | Aristides Bakandritsos Ravishankar G Kadam Pawan Kumar Giorgio Zoppellaro Miroslav Medved' Jií Tu
ek Tiziano Montini Ondej Tomanec Pavlína Andrýskov Bohuslav Draho Rajender S Varma Michal Otyepka Manoj B Gawande Paolo Fornasiero Radek Zboil |
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Affiliation: | Aristides Bakandritsos,Ravishankar G. Kadam,Pawan Kumar,Giorgio Zoppellaro,Miroslav Medved',Jiří Tuček,Tiziano Montini,Ondřej Tomanec,Pavlína Andrýsková,Bohuslav Drahoš,Rajender S. Varma,Michal Otyepka,Manoj B. Gawande,Paolo Fornasiero,Radek Zbořil |
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Abstract: | Single‐atom catalysts (SACs) aim at bridging the gap between homogeneous and heterogeneous catalysis. The challenge is the development of materials with ligands enabling coordination of metal atoms in different valence states, and preventing leaching or nanoparticle formation. Graphene functionalized with nitrile groups (cyanographene) is herein employed for the robust coordination of Cu(II) ions, which are partially reduced to Cu(I) due to graphene‐induced charge transfer. Inspired by nature's selection of Cu(I) in enzymes for oxygen activation, this 2D mixed‐valence SAC performs flawlessly in two O2‐mediated reactions: the oxidative coupling of amines and the oxidation of benzylic C? H bonds toward high‐value pharmaceutical synthons. High conversions (up to 98%), selectivities (up to 99%), and recyclability are attained with very low metal loadings in the reaction. The synergistic effect of Cu(II) and Cu(I) is the essential part in the reaction mechanism. The developed strategy opens the door to a broad portfolio of other SACs via their coordination to various functional groups of graphene, as demonstrated by successful entrapment of FeIII/FeII single atoms to carboxy‐graphene. |
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Keywords: | amine coupling C?H oxidation cooperative catalysis graphene single‐atom catalysis |
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