Exploration of Catalytic Activity of Quercetin Mediated Hydrothermally Synthesized NiO Nanoparticles Towards C–N Coupling of Nitrogen Heterocycles

A new approach towards the preparation of phase pure NiO nanoparticles via quercetin mediated hydrothermal method is proposed in this work. The performance of quercetin as capping agent is found to be good. The XRD and SEM results confirm that the NiO nanoparticles prepared with quercetin are smaller in size and have refined morphology than that prepared without quercetin. Thermal stability, elemental composition and particle size of prepared nanoparticles have been revealed by TG-DSC, EDAX and HR-TEM analysis respectively. N 2 adsorption–desorption isotherm (BET) analysis was done to reveal specific surface area. The prepared NiO nanoparticles act as cost effective, environmental friendly and efficient catalyst for the C–N cross coupling of indole and electron deficient pyrrole, under very mild reaction conditions. The catalytic system is able to tolerate many functional groups with different electronic and structural properties. Hence the present catalytic system may be possibly applied in large scale synthesis. Graphic Abstract