Novel covalent functionalization of graphene with porphyrin

The chemical functionalization of graphene is critical for incorporating the carbon layer into a variety of applications including electronic devices and sensors[1]. We investigate two possible chemical reactions between iron porphyrin and a metal supported graphene. On the one hand, covalent modification of graphene via Diels-Alder reactions is emerging as a key tool to achieve this goal. Usually, graphene functions as both C4 and C2 unit when paired with a Diels-Alder partner[2]. In our case, we take advantage of the peculiar interaction between the metal and graphene in some specific areas of the moiré pattern, where a C3 fragment of graphene can present a similar electronic structure as an allyl fragment[3]. Our proposed mechanism fulfills the Woodward-Hoffmann rules and establishes a novel reversible covalent functionalization of graphene which is controlled by the underlying metal substrate[4].