Nb2CT x Mxene-supported ultrafine palladium nanoparticles for aerobic oxidation of aromatic alcohols and one-pot synthesis of functionalized heterocycles.

MXene is a ubiquitous 2D nanomaterial and is widely used in many applications; however, its catalytic use in organic transformations remains unexplored. Here, we designed and developed palladium nanoparticles stabilised on Nb2CT x MXene (Pd/Nb2CT x ) and used the well-characterised nanocomposite as a heterogeneous catalyst for selective aerobic oxidation of benzylic primary and secondary alcohols to corresponding aldehydes and ketones with excellent efficiency. Interestingly, the catalytic application of Pd/Nb2CT x was successfully extended towards a one-pot tandem oxidative condensation strategy for the synthesis of biologically important dihydropyrimidinone/thione derivatives from benzyl alcohols, ethyl acetoacetate, and urea/thiourea. A versatile substrate scope was examined by altering the electronic environment, and good to excellent yields in all cases, ranging 70-98% reveals the vast applicability of the Pd/Nb2CT x nanocatalyst for organic synthesis. The catalyst also demonstrated excellent recyclability, examined up to six consecutive cycles. Furthermore, the recycled heterogeneous catalyst was found to be highly stable, as confirmed by PXRD and FE-SEM analysis. Next, mechanistic investigation deduced the importance of nanostructure as well as the crucial role of the oxygen environment for the catalysis. The present work paves a new way towards exploration of Pd/Nb2CT x MXene nanomaterial as an efficient and recyclable heterogeneous nanocatalyst for organic transformations.