The recovery of gold from primary mining deposits and secondary recycling sources is of great importance as demand for this precious metal continues to increase. Recently, several supramolecular recovery strategies have been reported, including our early work using tetralactam macrocycles. This presentation describes more recent studies using acyclic polyamide receptors to capture and co-precipitate AuX4- from solution. X-ray crystallography enabled a systematic evaluation of co-precipitates that included acyclic arylpolyamide receptor structures with 1,4- and 1,3,5- substitution patterns. In each crystal structure, the dominant non-covalent interactions were: (a) H-bonding between the amide NH residues of the receptor and halide ligands of the AuX4- anion, (b) stacking of the gold center against the π-electron rich aryl ring of the receptor, and (c) bridging of the two amide oxygens by a naked H+ as the countercation. To accommodate these dominant interactions there was substantial variation of the crystal lattice packing and the receptors with 1,3,5-substitution patterns produced a rich array of geometric variations in the solid-state.

Supramolecular co-precipitation of square planar gold complexes using acyclic polyamide receptors

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.