Stimuli‐Responsive Circularly Polarized Luminescence of Gold Clusters Based on Hydrogen‐Bond Driven Intercluster Coupling

Stimuli‐responsive circularly polarized luminescence (CPL) metal clusters hold significant potential in high‐security encryption and sensing applications, yet the exploration of hydrogen‐bond‐driven CPL‐active metal clusters remains limited. Here, we report the synthesis of an enantiomeric pair of rhomboid Au4 clusters utilizing chiral R/S‐4‐hydroxymethyl‐5‐methyloxazole‐2‐thione (R/S‐HMMT) ligands. Two enantiomeric pairs of self‐assembled metal clusters R/S‐Au4(HMMT)4‐blue and R/S‐Au4(HMMT)4‐red were obtained, by constructing distinct intercluster hydrogen bonds through the use of different crystalline solvents. In R/S‐Au4(HMMT)4‐blue, 1,4‐dioxane guest molecules were observed to form a hydrogen‐bond network with the hydroxyl groups of the cluster surface ligands. In contrast, a different hydrogen‐bond network involving the hydroxyl groups of the surface ligands was identified in R/S‐Au4(HMMT)4‐red, resulting in a distinct stacking pattern. The unique intercluster couplings mediated by hydrogen bonds result in R/S‐Au4(HMMT)4‐blue exhibiting a blue CPL emission at 466 nm, while R/S‐Au4(HMMT)4‐red shows a dual CPL emission at 446 and 727 nm. Theoretical calculations reveal that hydrogen‐bond driven intercluster couplings in R‐Au4(HMMT)4‐red are significantly stronger than in R‐Au4(HMMT)4‐blue. Additionally, both solid R/S‐Au4(HMMT)4‐blue and R/S‐Au4(HMMT)4‐red undergo reversible CPL transformations in response to organic vapors, temperature, or mechanical stimuli, due to the destruction and reconstruction of hydrogen‐bond networks. These characteristics make them promising materials for information encryption applications.