Abstract 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

中文翻译：

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槲皮素介导的水热合成氧化镍纳米颗粒对氮杂环碳氮偶联的催化活性探索

摘要 本文提出了一种通过槲皮素介导的水热法制备相纯NiO纳米颗粒的新方法。发现槲皮素作为封端剂的性能良好。XRD 和 SEM 结果证实，用槲皮素制备的 NiO 纳米颗粒比不加槲皮素制备的 NiO 纳米颗粒尺寸更小，形貌更精细。通过TG-DSC、EDAX和HR-TEM分析分别揭示了制备的纳米颗粒的热稳定性、元素组成和粒径。进行N 2 吸附-解吸等温线(BET) 分析以揭示比表面积。在非常温和的反应条件下，制备的 NiO 纳米粒子可作为吲哚和缺电子吡咯的 C-N 交叉偶联的经济、环保和高效的催化剂。催化体系能够耐受许多具有不同电子和结构特性的官能团。因此，本催化体系有可能应用于大规模合成。图形摘要