Zhu et al. have reported the synthesis of S@Ag40.13Cu13.87S18(S t Bu)20(SO3 t Bu)12 containing both Ag and Cu as metals under reaction conditions similar to those used in our study. However, in our study, X@Ag54, which contains only Ag as the metal, was synthesized (Figure ). In our study, unlike the research by Zhu et al., we did not add the reducing reagents, such as borane amine complexes, into the reaction solvent. Moreover, compared to their study, we significantly reduced the amount of Cu 2+ catalyst relative to Ag + (1.260 vs 0.198 atom %). These factors likely contributed to the successful synthesis of X@Ag54 with only Ag as the metal, which enabled the encapsulation of I -.