Preparation of lead dodecyl sulfate nanorod materials mediated by mechanochemistry and green solvent-free catalytic synthesis of heterocyclic derivatives†

In this work, the lead dodecyl sulfate material (Pb(DS)₂) was successfully synthesized for the first time via a mechanochemical ball milling method. The synthesized material was comprehensively analyzed using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that the Pb(DS)₂ catalyst, synthesized via solvent-free mechanical ball milling, possesses a distinctive solid nanorod morphology. Furthermore, the catalyst efficiently promotes the synthesis of heterocyclic derivatives in a solvent-free environment within 20 minutes, achieving a target product yield of up to 98%. Specifically, it produced bis(indolyl)methane derivatives with yields ranging from 78% to 98%, and quinoxaline derivatives with yields ranging from 87% to 98% within the same timeframe. The Pb(DS)₂ catalyst also exhibits remarkable catalytic activity in the Biginelli reaction. Notably, the catalyst maintains excellent and stable performance over eight recycling cycles.