Deep eutectic solvents and heterogeneous catalysis with metallic nanoparticles: A powerful partnership in sustainable synthesis

The last decade has seen a remarkable interest in Deep Eutectic Solvents (DESs), usually obtained from biorenewable, cheap and non-toxic precursors, as effective environmentally responsible reaction media for transition-metal-catalyzed organic transformations. One of the main advantages associ-ated with the use of these neoteric solvents is the ease of recyclability of both the catalytic system under study and the eutectic mixture, which paves the way for their implementation in heterogeneous catalysis. In this Current Opinion, a discus-sion is offered to highlight recent studies published, in particular since 2018, in which transition-metal-based nanoparticles have been efficiently coupled with DESs in the following synthetic protocols: i) C-C and C-X (X = N, O, S) coupling reactions; ii) oxidation/reduction processes; iii) synthesis of heterocycles/ cycloisomerizations; and iv) polymerization reactions.