Au-involving chalcogen bond in 4-(2-chalcophenyl)-1,2,3-triazolylidene Au(I) complexes: synthesis, characterization, and photophysical properties.

Noncovalent interactions, particularly chalcogen bonds (ChBs), have gained prominence in modern chemistry due to their tunability and directionality. We present a pioneering investigation of a d metal-involving ChB in triazolylidene Au(I) complexes. The crystal structures reveal the occurrence of intramolecular ChBs between Au(I) and chalcophene substituents positioned on the wingtip of triazolylidene ligands. The strength of these ChB interactions can be effectively modulated by altering the chalcophene moieties and ancillary ligands associated with Au(I). The neutral LAu(I)X complexes exhibit remarkable phosphorescence, with photoluminescence quantum yield (PLQY) reaching up to 70% in the solid state, which is attributed to their rigid structure with intramolecular ChB interactions between the Au and chalcogen atoms. Moreover, density functional theory (DFT) calculations were performed to obtain insights into the nature of the ChB interactions.