Graphene Quantum Dots Modified with Metformin/Co(II) as Efficient Oxidation Catalyst

While one of the valuable approaches to obtaining a heterogeneous catalyst is supporting them on a high surface area supports, the strategy mainly suffers from the low number of chelating agents on most of the supports to grip the metal cations catalysts. Therefore, loading multidentate compounds susceptible to binding with metal cations is a potent strategy to improve the catalyst stability on the support. In this report, metformin as a multi-dentate ligand was bonded onto graphene quantum dots as a high aspect ratio compound to afford new support susceptible to chelating Co(II). Deposition of Co(II) on graphene quantum dots modified with metformin gave a new sustainable heterogeneous catalyst that was highly active in the oxidation of alkyl arenes. The reactions were performed in solvent-free conditions at 80 ºC with high conversions up to 96%. The organometallic compound is applicable as a recoverable heterogeneous catalyst with recyclability up to 6 times. The modification of graphene quantum dots with metformin also can gain more attention from medicinal researchers.