Decatungstate Photocatalyzed Acylation of 2D Transition Metal Dichalcogenides

Abstract

2D Transition metal dichalcogenides (TMDs) and their unique chemistry have flourished in the recent years owing to their pertinence in a broad series of front-row applications including electronic, opto-epectronic and energy storage /harvest devices for the semiconductors,1, 2 while also catalysis and photo /electrothermal applications for the metallic phases.3 Since their ability to protagonist in such applications is dependent on their chemical structure and processing, a great deal of research effort has been focused on TMDs’ functionalization. The nucleophilic nature of the metallic phase is responsible for the uneven flourish, regarding covalent functionalization, in favor of the metallic phase vs the semiconducting. In parallel, the main inspiration for such chemical transformations on 2D TMDs has been organic chemistry. However, until now there is no report based on a catalytic protocol for the covalent functionalization of TMDs. Following our previous report on the catalytic transformation of single walled carbon nanotubes,4 we herein present the decatungstate-photocatalyzed acylation of 2H-MoS2 and 2H-MoSe2, employing aliphatic and aromatic aldehydes (Figure 1). The successful protocol is accompanied by detailed optimization and spectroscopic characterization. The availability of the various aldehydes as means to realize chemical modifications of choice on the surface of 2H phase of TMDs and the mild reaction conditions protocol, shape an ideal methodology to advance the chemistry of 2D TMDs bringing them one step closer to industry applications.