Application of Magnetically Recoverable Core–Shell Nanocomposite in the Synthesis of Bis(indolyl)methanes at Room Temperature

A sulfonated polyethylene glycol-supported nano-magnetite (Fe3O4@PEG-SO3H) has been prepared, characterized, and evaluated as a magnetically recoverable core–shell nanocomposite catalyst for the synthesis of bis(indolyl)methane derivatives through the one-pot reaction of indole and aldehydes. Green and eco-friendly reaction profile, mild reaction conditions (room temperature), simple procedure, short reaction times, and excellent yields make this method versatile and demonstrate its practical merit for the synthesis of the title compounds with potential pharmacological activity. Furthermore, the excellent catalytic performance, thermal stability, and easy separation and reusability of the prepared nanocatalyst without significant deterioration in its catalytic activity make it a good heterogeneous system and a superior alternative to the existing protocols.