In Situ generated PdNPs immobilized on polystyrene supported DABCO Dicationic ionic liquid: An efficient and reusable catalyst for Suzuki and Heck coupling reactions

Abstract

A catalyst named PdNPs-DDIL@PS has been synthesized by immobilizing PdNPs on a DABCO Dicationic Ionic Liquid (DDIL) supported on Merrifield Resin (PS). The PdNPs (∼4.16 nm size) generated in situ were fully characterized using different techniques such as SEM, TEM, TGA-DTA, and XPS. It has been found that the catalyst is highly active in the Suzuki coupling reaction of various aryl bromides and aryl boronic acids in 70 % aqueous ethanol at room temperature. The catalyst produced the desired Suzuki coupling products in good to excellent yields. Additionally, the protocol was extended for the Heck coupling reactions in DMF at 80 °C with good to excellent yields. The catalyst attained a good turnover number (TON) of 160.00–189.92 and a turnover frequency (TOF) of 8.493–18.992 min⁻¹ for the Suzuki and TON of 173.33–189.77 and TOF of 3.952–6.325 min⁻¹ for the Heck coupling reactions. The catalyst displayed at least four times recyclability for the Suzuki coupling without a substantial decrease in product yields. Additionally, it boosts impressive environmentally-friendly credentials in Suzuki coupling reactions.