Resorcinarene bearing carbanion ion pair as organocatalyst for carbon dioxide fixation

The development of efficient and environmentally friendly catalysts for carbon dioxide (CO₂) cycloaddition remains a significant challenge due to the corrosion, pollution, and purity issues caused by conventional halide-containing systems. Herein, we present a halide-free tetra-1,3-diketone resorcinarene ion pair organocatalyst that facilitates CO₂ fixation under mild conditions (120 °C, 0.1 MPa) through a dual activation mechanism—CO₂ activation by the resorcinarene carbanion and epoxide activation via H-bonding. This catalytic system has been shown to achieve high conversion (83–99 %) for terminal epoxides, retain notable activity for internal epoxides, and demonstrate exceptional thermal stability (>230 °C) and recyclability (five cycles without significant loss of activity). This system offers a sustainable alternative to traditional halide catalysts, combining environmental advantages with practical industrial feasibility.