Crystal Structure and Optical Properties of the [Ag₆₂S₁₂(SBu^t)₃₂]²⁺ Nanocluster with a Complete Face-Centered Cubic Kernel

The crystal structure of the [Ag₆₂S₁₂(SBu^t)₃₂]²⁺ nanocluster (denoted as <b>NC-I</b>) has been successfully determined, and it shows a complete face-centered-cubic (FCC) Ag₁₄ core structure with a Ag₄₈(SBu^t)₃₂ shell configuration interconnected by 12 sulfide ions, which is similar to the [Ag₆₂S₁₃(SBu^t)₃₂]⁴⁺ structure (denoted as <b>NC-II</b> for short) reported by Wang. Interestingly, <b>NC-I</b> exhibits prominent differences in the optical properties in comparison with the case of the <b>NC-II</b> nanocluster. We employed femtosecond transient absorption spectroscopy to further identify the differences between the two nanoclusters. The results show that the quenching of photoluminescence in <b>NC-I</b> in comparison to that of <b>NC-II</b> is caused by the free valence electrons, which dramatically change the ligand to metal charge transfer (LMCT, S 3p → Ag 5s). To get further insight into these, we carried out time-dependent density functional theory (TDDFT) calculations on the electronic structure and optical absorption spectra of <b>NC-I</b> and <b>NC-II</b>. These findings offer a new insight into the structure and property evolution of silver cluster materials