Fe3O4@SiO2-SO3H-DABCO: A novel magnetically retrievable bifunctional catalyst for ecofriendly synthesis of diheteroarylmethanes

Abstract

Developing sustainable methodologies using green solvents, reusable catalysts and energy saving approaches is the need of time considering the growing stringent environmental regulations. The present study reports the novel three-step synthesis of magnetically separable Fe3O4@SiO2-SO3H-DABCO core-shell magnetic nanocomposite catalyst and evaluation of its catalytic efficiency involving the synthesis of structurally diverse diheteroarylmethanes via one-pot reaction of indoles, aryl aldehydes and 4-hydroxycoumarin in aqueous ethanol (50:50 v/v) at ambient conditions. The catalyst could be recycled for six consecutive runs without significant change in catalytic activity or the product yields. The ecofriendly synthetic approach offers several advantages such as the use of a green solvent system, ambient reaction conditions, shorter reaction times, excellent yields and ease of separation of the catalyst using an external magnet.