Coinage Metal Superatomic Cores: Insights into Their Intrinsic Stability and Optical Properties from Relativistic DFT Calculations

Abstract

Coinage-metal atomically precise nanoclusters are made of a well-defined metallic core embedded in a ligand-protecting outer shell. Whereas gold derivatives are particularly well documented, examples of silver nanoclusters are somewhat limited and copper species remain particularly scare. Our DFT relativistic calculations on superatomic metallic cores indicate that copper species are almost as stable as gold clusters and more stable than their silver counterparts. Thus, for silver superatomic cores, the role of the stabilizing ligands is more crucial in the stabilization of the overall structure, in comparison to copper and gold. Hence, the chemistry of the earlier counterparts of gold, especially copper, should grow quickly with at least characterizations of species related to that found in the heavier elements in the triad, which requires tackling synthetic challenges. Time-dependent (TD)-DFT calculations show that with an increase of the cluster core nuclearity, the absorption bands are redshifted, allowing us to differentiate between the clusters types. Moreover, the optical properties of the silver cores are fairly different from that of their Cu and Au relatives.

[M16Ni24(CO)40]4–: Coinage Metal Tetrahedral Superatoms as Useful Building Blocks Related to Pyramidal Au20 Clusters (M = Cu, Ag, Au). Electronic and Bonding Properties from Relativistic DFT Calculations

“…A Morokuma-Ziegler decomposition of the bonding energy [50][51][52] 58 In fact, in such bare metal clusters Ag behaves always a bit differently than Cu and Ag, because the periodical trend is likely to be counterbalanced by the relativistic effects. 58 Table 1), whereas that of its (n + 1)p σ AO remains lower than 0.1 e in the three clusters. The less important e and t 1 contributions of the orbital interaction energy (Table 1) (Figure 1), each of the four Ni 6 (CO) 3 (µ-CO) 6 (µ -CO) units has local C 3v symmetry.…”

Nature of mercury inclusion in intermediate 6‐valence electron [M@Au8Hgx(PPh3)8]n+ (M = Au, Pd, Pt; x = 0‐2) protected gold superatoms: Insights from relativistic density functional theory calculations

“…The resulting shell structure in I exhibits 6‐ ve (Au + 8xAu‐q = 6‐ ve ; Pd/Pt + 8xAu‐q = 6‐ ve ), which are distributed in an 1S 2 1P x 2 1P y 2 shell structure, denoted as 1S 2 1P 4 for simplicity (Figure ). Owing to the oblate shape of the M@Au 8 core, the 1P z shell remains as a low‐lying unoccupied orbital, in contrast to spherical shape cluster (as the icosahedral [Au 13 ] 5+ core), depicting an almost degenerated 3‐fold 1P shell. Thus, in I , a 6‐ ve count is favored in contrast to the 8‐ ve .…”

Bonding and properties of superatoms. Analogs to atoms and molecules and related concepts from superatomic clusters

“…The intrinsic stabilities of the bare superatomic cores usually found in ligand‐protected clusters have been explored by Gam, for M 4 2+ , M 13 5+ , M 32 14+ , and M 43 9+ , expanding the study to the whole coinage metal group. In addition, the specific optical spectrum patterns, vibrational properties and spin‐orbit coupling effects for each isolated superatomic core was given.…”