Coskun Research Group has published a new article in Angewandte Chemie titled “Porous Phenazine-bridged Tetraoxa[8]Circulenes for Selective Gold Recovery and Heterogeneous Catalysis”. 

To read the article: https://onlinelibrary.wiley.com/doi/epdf/10.1002/anie.6586260?domain=p2p_domain&token=RESIWZZAUGQCDAZZE4E3

ABSTRACT

The sustainable recovery of precious metals is critical for securing strategic resources while reducing the environmental footprint ofmining. Among these, the selective recovery of gold from electronic waste represents a particularly attractive yet challenging target.Herein, we report the synthesis of phenazine-based porous tetraoxa[8]circulene, PpTOC, incorporating heterocyclic crown ethermoieties for efficient gold capture. The PpTOC combines a high surface area over 1200 m 2 g− 1 with aza-crown ether-like cavitiesand high heteroatom content, enabling high gold uptake capacities of up to 860 mg g− 1 under acidic conditions. Importantly, thepolymer demonstrates selective recovery of gold from electronic waste even in the presence of high concentrations of competingmetal ions such as copper. The recovered material, containing a mixture of Au(III), Au(I), and Au(0) species, has been directlyemployed as a heterogeneous catalyst in a sequential alkylation–annulation reaction. Critically, switching from aprotic toluene toprotic ethanol redirects the reaction outcome from alkylation to annulation, enabling divergent product selectivity using the sameheterogeneous catalyst simply by changing the solvent.