Chalcogens-Induced Ag6Z4@Ag36 (Z = S or Se) Core–Shell Nanoclusters: Enlarged Tetrahedral Core and Homochiral Crystallization

Control over core structure is much more challenging than that over shell structure in core–shell silver nanoclusters. Herein, two isostructural chalcogen-mediated Ag6Z4@Ag36 (Z = S or Se) nanoclusters (SD/Ag42a and SD/Ag42b) caging tetrahedral Ag6Z4 as cores were synthesized by introducing Ph3CSH or Ph3PSe as slow-release source of S2– or Se2–, respectively, and characterized by single-crystal X-ray diffraction (SCXRD). As compared to the previously reported AgS4@Ag36 cluster (Ag37), we found that introducing additional S2– or Se2– ions can effectively enlarge the inner core from tetrahedral AgS4 to Ag6Z4, which is a regular octahedron of silver with four Z2– capping on one tetrahedral set of four faces. More interestingly, the molecular enantiomers of SD/Ag42a and SD/Ag42b segregate into different crystals (P212121), while those of Ag37 form racemic crystals (I41/acd). The larger Ag6Z4 core in Ag42 clusters also extends their emission to the near-infrared region (∼760 nm). The study confirms that chalcogenide can enlarge the nuclearity of nanoclusters by altering the inner core structure and affords a new strategy to synthesize chiral core–shell silver nanoclusters of higher-order in controlled fashion.