Extended π-Conjugation and iClick Turn-on of Phosphorescence

Gold(I) complexes continue to attract attention for their distinctive photophysical properties, driven in part by their capacity to engage in aurophilic bonding. We report a new series of digold(I) triazolate complexes incorporating polycyclic aromatic hydrocarbon (PAH) substituents, naphthalene, anthracene, and pyrene, constructed via inorganic click (iClick) chemistry. The resulting complexes exhibit pronounced changes in optical behavior compared to their mononuclear analogues, including dual emission and phosphorescence arising from enhanced spin-orbit coupling and charge-transfer processes. UV-visible absorption and emission spectroscopy reveal bathochromic shifts and vibronic progression with increasing π-conjugation of the PAH ligands. Comparative photophysical studies demonstrate that digold(I) species display augmented ligand-to-metal and metal-to-ligand charge-transfer character, underscoring the role of gold-gold interactions and ligand design in modulating emissive behavior. These findings provide new insights into the structure-property relationships of Au(I) complexes and expand the design space for luminescent organometallic materials.