Efficient and reusable catalysis of benzylic C-H oxidation over layered [Co(OH)] derivatives.

Aerobic oxidation of benzylic C(sp)-H bonds in a green and heterogeneous manner is a major target in organic catalysis. Herein, we report the synthesis of 3D coordination polymers containing [Co(OH)] layers, affording reusable and efficient oxidation of ethylbenezene and tetralin by using O as the oxidant. Moreover, the cleavage of Co-carboxylate bonding renders atomically thin cobaltate nanosheets and enhanced catalytic performance. This is one of the top catalytic performances for Co-catalyzed benzylic C(sp)-H oxidation (∼0.02 mol% Co and 76% conversion for nanosheets), ascribed to the exposed, accessible and coordinatively unsaturated Co species.