Controlled Shell and Kernel Modifications of Atomically Precise Pd/Ag Superatomic Nanoclusters

Abstract

The first 8-electron Pd/Ag superatomic alloys with an interstitial hydride [PdHAg 19 (dtp) 12 ] (dtp = S 2 P(O i Pr) 2 À ) 1 and [PdHAg 20 (dtp) 12 ] + 2 are reported. The targeted addition of a single Ag atom to 1 is achieved by the reaction of one equivalent of trifluoroacetic acid, resulting in the formation of 2 in 55 % yield. Further modification of the shell results in the formation of [PdAg 21 (dtp) 12 ] + 3 via an internal redox reaction, with the system retaining an 8-electron superatomic configuration. The interstitial hydride in 1 and 2 contributes its 1s 1 electron to the superatomic electron count and occupies a PdAg 3 tetrahedron. The distributions of isomers corresponding to different dispositions of the outer capping Ag atoms are investigated by multinuclear VT NMR spectroscopy. The emissive state of 3 has a lifetime of 200 μs (λ ex = 448; λ em = 842), while 1 and 2 are non-emissive. The catalytic reduction of 4-nitrophenol is demonstrated with 1-3 at room temperature.

Recent progress in dichalcophosphate coinage metal clusters and superatoms

“…Treatment of [PdHAg 19 (dtp) 12 ] with CF 3 COOH or HBF 4 triggers an internal redox reaction, yielding another 8-electron alloy [PdHAg 20 (dtp) 12 ] + . 84 Both PdHAg 19 and PdHAg 20 contain a PdH-centred icosahedron Ag 12 , which resembles that of PtH@Ag 12 (Fig. 7).…”

“…By contrast, the hydrido ligands of other discussed clusters serve as charge-balancing ions solely. As suggested by DFT data, 84 the Pd–H unit of [PdHAg 19 (dtp) 12 ] and [PdHAg 20 (dtp) 12 ] + is formed by interaction of 4d z 2 (Pd) and 1s(H) atomic orbitals to give populated σ(Pd–H) and unpopulated σ*(Pd–H) molecular orbitals. Owing to the strong destabilization of the σ*(Pd–H) orbital, the unpaired electron occupies the 5s(Pd) orbital, thereby contributing to the building of the superatomic orbitals.…”

“…In 2023, the structurally related cluster [PdHAg 19 (dtp) 12 ] was obtained in 17% yield via co-reduction of [Ag(CH 3 CN) 4 ]BF 4 and Pd(OAc) 2 in the system “NaBH 4 – NH 4 [S 2 P(O i Pr) 2 ]”. 84 Essentially, the new PdHAg 19 cluster is the first 8-electron Pd/Ag superatomic alloy with an interstitial hydride. Although the PdH motif is quite abundant in classical coordination chemistry, the PdH-doped coinage metal clusters are still limited to ligand-supported (HPd@Au 10 ) 3+ and (HPd@M 2 Au 8 ) 3+ (M = Ag and Cu) species.…”

“…The remarkable feature of the clusters [PdHAg 19 (dtp) 12 ], 84 [PdHAg 20 (dtp) 12 ] + and [PtHAg 19 (dtp/dsep) 12 ] 82 lies in the fact that their hydrido ligands provide the central Pt/Pd atom with the electron to complete the superatomic 8-electron count with the other metals. By contrast, the hydrido ligands of other discussed clusters serve as charge-balancing ions solely.…”

Hydride Doping Effects on the Structure and Properties of Eight-Electron Rh/Ag Superatoms: The [RhHx@Ag21–x{S2P(OnPr)2}12] (x = 0–2) Series

“…We have recently shown that interstitial hydrides connected to noble metals, whose electronegativity values are larger than H, exhibit properties that differ from those of conventional ligands. 13,31 Therefore, accurately identifying the hydride position is important, as hydrides may exhibit different properties at different positions. Also, an interesting question is: can an 1a).…”