Part I. Figure S1. Calculated bond distances of the [Oct 4 N + ][Au 25 (SCH 2 CH 2 Ph) 18-] crystal structure and the Au 25 (SCH 2 CH 2 Ph) 18 cluster. Part II. Table S1. Point group analysis of the neutral and anionic Au 25 (SR) 18 clusters. The analysis includes only the 43 atoms of the Au 25 S 18 framework. Part III. Table S2. Full determination of the Point Groups of the studied Au 25 clusters, at the calculated tolerances. Part IV. Figure S2. Kohn-Sham energy levels of the anionic Au 25 (SR) 18 cluster for 11 distinct R-groups.
This report addresses a density functional theory study of the vibrational normal modes of small-sized thiolate-protected gold clusters. Calculated far-infrared (far-IR) and lowfrequency Raman spectra of established thiolate-protected gold clusters (4,12,18, 19,20, 24, and 25 Au atoms) show characteristic peaks in the range of 20−350 cm −1 that can be attributed to the breathing mode of the gold core, Au−S−Au bending modes and Au−S stretching modes. It was found that as cluster size increases the Au 13 breathing mode of Au 25 cluster emerges. This study reveals both systematic and specific characteristics that may provide a basis for identification ("fingerprinting") by far-IR and low-frequency Raman spectroscopy of the many diverse gold− thiolate cluster compounds.
The structure and bonding of the gold-subhalide compounds Au144Cl60[z] are related to those of the ubiquitous thiolated gold clusters, or Faradaurates, by iso-electronic substitution of thiolate by chloride. Exact I-symmetry holds for the [z] = [2+,4+] charge-states, in accordance with new ESI-MS measurements and the predicted electron shell filling. The High symmetry facilitates analysis of the global structure as well as the bonding network, with some striking results.
The structure of the Au15-thiolate cluster has been elucidated using a DFT approach, and it is demonstrated to comprise a Au4-tetrahedron core protected solely by the combination of two concatenated staple motifs. The longer motif efficiently wraps the core, and threads the shorter one. The structural assignment is supported by comparison to the powder X-ray diffraction pattern and, via time dependent-DFT calculations, to the optical and chiroptical (CD) absorption spectra. The calculated CD spectrum features a characteristic strong peak centered at 3.48 eV in accordance with the experimental profile. These results confirm the existence of long Au(I)-thiolate motifs as protecting units of small thiolated gold clusters with a thiolate-to-gold ratio comparable to the Au15(SR)13 cluster.
The structure of the recently discovered Au130-thiolate and -dithiolate clusters is explored in a combined experiment-theory approach. Rapid electron diffraction in scanning/transmission electron microscopy (STEM) enables atomic-resolution imaging of the gold core and the comparison with density functional theory (DFT)-optimized realistic structure models. The results are consistent with a 105-atom truncated-decahedral core protected by 25 short staple motifs, incorporating disulfide bridges linking the dithiolate ligands. The optimized structure also accounts, via time-dependent DFT (TD-DFT) simulation, for the distinctive optical absorption spectrum, and rationalizes the special stability underlying the selective formation of the Au130 cluster in high yield. The structure is distinct from, yet shares some features with, each of the known Au102 and Au144/Au146 systems.
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