Nanonickel Oxides Prepared by Atomic Layer Deposition as Efficient Catalyst for the Dehydrogenation of N‐Heterocycles

Abstract An efficient heterogeneous catalyst nickel oxide supported on graphene nanoplatelets (NiO/Gr) has been developed for the aerobic and additive‐free dehydrogenation of N‐heterocycles. This catalyst was easily prepared by atomic layer deposition from nickel(II) diketonate–diamine and ozone, which has advantages of excellent activity, low metal loading, simple preparation, stability for multiple reuse. The reactions proceed in good yields with broad substrate scope under mild conditions by using tiny quantity of catalyst. Interestingly, pharmaceutically relevant tetrahydro‐ β ‐carboline derivative can also be oxidized successfully to afford the important intermediate. The control experiments suggest that this catalytic dehydrogenation experiences radical‐type oxidation.