Mild Covalent Functionalization of Transition Metal Dichalcogenides with Maleimides: A “Click” Reaction for TMDCs

The physical properties of ultrathin transition metal dichalcogenides (2D-TMDCs) make them promising candidates as active nanomaterials for catalysis, optoelectronics, and biomedical applications. Chemical modification of TMDCs is expected to be key in modifying/adding new functions that will help make such promise a reality. We present a mild method for the modification of the basal planes of 2H-MoS₂ and WS₂. We exploit the soft nucleophilicity of sulfur to react it with maleimide derivatives, achieving covalent functionalization of 2H-TMDCs under very mild conditions. Extensive characterization proves that the reaction occurs through Michael addition. Our results adapt one of the most popular “click” reactions in polymer chemistry and biochemistry to obtain a powerful tool for the chemical manipulation of TMDCs.