Pd Nanoparticles Decorated on Jute Sticks: Dip-Catalyst of Suzuki-Miyaura and Mizoroki-Heck C–C Bond Formation Reactions in Water

Achieving C−C bond formation using Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions with reusable, cost-efficient, highly regioselective, and naturally available supported catalysts is rare and challenging. In the current study, naturally available jute plant sticks (green support - GS) decorated with Pd nanoparticles, denoted as Pd@GS, were prepared by reducing K₂PdCl₄ using NaBH₄ in water. This ‘dip-catalyst’ construct was used to catalyze the Suzuki-Miyaura and Mizoroki-Heck cross coupling-reactions in water. SEM, TEM, and elemental mapping images reveal the homogeneous distribution of Pd nanoparticles with average dimensions within a narrow range of 7–10 nm on solid support. For the Suzuki-Miyaura cross-coupling reaction, the highest conversion achieved is 97% with a TOF of 4692 h⁻¹ for the reaction of 4-acylphenylboronic acid and iodobenzene in the presence of KOH in an aqueous medium. For the Mizoroki-Heck reaction, a 98% yield (TOF=237 h⁻¹) of the coupling product was obtained with an exclusive selectivity towards the targeted olefinic product using 4-methylstyrene and iodobenzene as the reactants in water-DMF as a mixed solvent at 90 °C. The same catalyst sample can be used for 7 consecutive cycles, i. e., without addition of any fresh catalyst, while retaining its original crystallinity without any leaching of Pd.