Abstract

Herein, we report Pt single atom (SA) – nanoparticle (NPs) supported on reduced titania nanotubes as an alternative route to obtain 3-methylindole (3-ML) from nitrobenzene and acetol as starting materials. 1 wt% Pt catalyst supported on TiO2, pristine titania nanotubes and reduced titania were prepared and characterized by techniques such as EPR, DRX, HR-TEM, N2 adsorption-desorption isotherms, to confirm the obtention Pt SA-NPs systems with sizes between 1.5 and 4.8 nm. The catalyst on reduced titania possesses improved activity and selectivity in the synthesis of 3-ML compared to the control systems, showing a high-moderate production of the heterocycle only in the presence of Pt SA. The temperature effect and a series of 4-substituited nitrobenzenes were used to evaluate the scope of the obtained catalyst in the production of indoles scaffolds. Recyclability studies show that the best catalyst proves to have an important efficiency obtaining conversion of nitrobenzene higher than 98 % and active for 7 consecutive reaction cycles. To the best of our knowledge our results are pioneers in the catalytic synthesis of 3-methylindole using nitrobenzene and acetol since it is an unexplored reaction route. © 2025 Elsevier B.V.