Catalytic properties of Ag-PolyaminoβCD NPs for reduction of nitroarenes

The reduction of nitroarenes is a key reaction involved in the synthesis of several compounds such as drugs, pesticides or dyes. During the last years Pd and Ag NPs have been used as catalysts to carry out this reaction with NaBH4. However several mechanistic aspects of the process are still unclear; in particular there is not agreement about the kinetic order of these reactions, whether 0-th or 1-st order in the substrate[1]. The aim of this work is to use a novel catalytic systems constituted by Ag-NPs coated with different polyamino-βCDs (Figure 1)[2], to carry out the reduction of some aromatic nitrocompounds using NaBH4 as the reducing agent, and to determine the kinetic features of these processes. The results showed the coexistence of two parallel reactive processes of zero and first order respectively (working under pseudo-first order conditions with respect to NaBH4). The peculiar dependence of the observed kinetic constants on the catalyst concentration was explained considering the surface of Ag-NPs as subdivided in “surface units” with a different degree of coverage by the polyamino-βCD coating