A Recyclable Trinuclear Bifunctional Catalyst Derived from a Tetraoxo Bis-Zn(salphen) Metalloligand

A tetraoxo bis‐Zn(salphen) supramolecular host can bind various divalent metal salts, thereby providing access to trinuclear bifunctional systems that incorporate both Lewis acid sites and dynamically bound nucleophilic anions. The formation of these trinuclear species was investigated and their stability features were also determined. The application of these trinuclear complexes as bifunctional catalysts was evaluated in the formation of cyclic organic carbonates from epoxides and CO2. The catalytic data, in combination with control experiments, clearly demonstrate that these trinuclear compounds show much higher recycling potential compared to various control compounds and they can be used in up to five cycles without an observable loss in activity. Furthermore, this new recyclable catalytic system does not require any additives and can be applied under solvent‐free conditions. A recyclable threesome: Highly stable supramolecular trinuclear complexes have been derived from a bis‐Zn(salphen) metalloligand in almost quantitative yield and can act as bifunctional catalysts in the synthesis of organic carbonates from epoxides and CO2 under solvent‐free conditions. These complexes have high recycling potential and can be used in up to five cycles without significant loss in substrate conversion and product yield.