Development of an innovative, green and recyclable switch-molecule-modified GO electrode for preventing Cu NP loss and catalyst deactivation in electro-organic reactions: application in Castro–Stephens coupling

Abstract

Porous organic substrate electrodes employed in electro-organic transformations often suffer from central metal leaching during repeated catalytic cycles, resulting in reduced activity, poor stability, and environmental concerns, which hinder their practical and commercial application. In this study, we aimed to overcome these limitations by designing a robust and recyclable graphene oxide (GO)-based electrode modified with OHPN@Cu. The electrode was synthesized and comprehensively characterized using FT-IR, SEM, EDS, CV, XPS, BET, TGA, and XRD techniques to elucidate its structural, morphological, and electrochemical properties. Owing to the intrinsic switching-molecule behavior of OHPN, the engineered electrode effectively immobilizes the Cu center, suppressing metal leaching during electrochemical operation. The catalytic performance of the GO-OHPN@Cu electrode was evaluated in the Castro–Stephens coupling of ethynylbenzene derivatives 1(a–c) with chlorobenzene derivatives 2(a–k) under optimized electrochemical conditions (60 °C, 1.5 h, 8 mA). The reactions afforded prop-1-yne-1,3-diyldibenzenes 3(a–l) in excellent yields ranging from 88 to 98%. This work introduces a novel switching-molecule behavior electrode which demonstrates enhanced catalytic efficiency, long-term stability, reusability, and environmental compatibility while minimizing environmental metal release, highlighting its potential for sustainable electro-organic transformations.