Recyclable CuS quantum dots as heterogeneous catalyst for Biginelli reaction under solvent free conditions

CuS Quantum dots (QDs) of 2-3 nm size have been synthesized in very high yield in 2 min using microwave and water as medium. The obtained QDs have been characterized by UV-visible spectrophotometer, XRD, TEM and SAED. CuS QDs have been used as a nanocatalyst to carry out Biginelli reaction in solvent free conditions. CuS QDs exhibit good catalytic activity for synthesis of dihydropyrimidinones with excellent yield. The catalyst takes less time as compared to other catalysts. It has attractive features like reduced reaction time, higher yields, ease of product isolation, economic availability of catalyst, simple procedure, and no harmful byproduct. The spent heterogeneous catalyst have been recovered by simple filtration and reused for multiple cycles. Kinetic studies have been carried out for the synthesis of both CuS QDs as well as Biginelli reaction products and rate constants have also been estimated. (C) 2014 Elsevier B.V. All rights reserved.