Doping-Mediated Energy-Level Engineering of M@Au Superatoms (M=Pd, Pt, Rh, Ir) for Efficient Photoluminescence and Photocatalysis.

We synthesized a series of MAu (dppe) Cl (MAu ; M=Au, Pd, Pt, Rh, or Ir; dppe=1,2-bis(diphenylphosphino)ethane), which have icosahedral M@Au superatomic cores, and systematically investigated their electronic structures, photoluminescence (PL) and photocatalytic properties. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was expanded when doping an M element positioned at the lower left of the periodic table. The PL quantum yield was enhanced with an increase in the HOMO-LUMO gap and reached 0.

Photoluminescence of Doped Superatoms M@Au (M = Ru, Rh, Ir) Homoleptically Capped by (Ph)PCHP(Ph): Efficient Room-Temperature Phosphorescence from Ru@Au.

A series of doped gold superatoms M@Au (M = Ru, Rh, Ir) was synthesized by capping with the bidentate ligand (Ph)PCHP(Ph). A single-crystal X-ray diffraction analysis showed that all the M@Au superatoms had icosahedral motifs with a significantly higher symmetry than that of the pure Au counterpart due to different coordination geometries. The Ru@Au superatom exhibited a room-temperature phosphorescence with the highest quantum yield of 0.

Ligand-protected gold/silver superatoms: current status and emerging trends.

Monolayer-protected gold/silver clusters have attracted much interest as nano-scale building units for novel functional materials owing to their nonbulk-like structures and size-specific properties. They can be viewed as ligand-protected superatoms because their magic stabilities and fundamental properties are well explained in the framework of the jellium model. In the last decade, the number of ligand-protected superatoms with atomically-defined structures has been increasing rapidly thanks to the well-established synthesis and structural determination by X-ray crystallography.

Understanding Doping Effects on Electronic Structures of Gold Superatoms: A Case Study of Diphosphine-Protected M@Au (M = Au, Pt, Ir).

Dopants into ligand-protected Au superatoms have been hitherto limited to group X-XII elements (Pt, Pd, Ag, Cu, Hg, and Cd). To expand the scope of the dopants to the group IX elements, we synthesized unprecedented [IrAu(dppe)Cl] [; dppe = 1,2-bis(diphenylphosphino)ethane] and [PtAu(dppe)Cl] () and compared their electronic structures with that of [Au(dppe)Cl] (). Single-crystal X-ray diffractometry, P{H} NMR, and Ir L-edge extended X-ray absorption fine structure analysis of revealed that the single Ir atom is located at the center of the icosahedral IrAu core.

Synthesis of Trimetallic (HPd@MAu) Superatoms (M = Ag, Cu) via Hydride-Mediated Regioselective Doping to (Pd@Au).

We have recently reported that hydride (H) doped superatom (HPd@Au) protected by eight PPh ligands selectively grew into (HPd@Au) by the nucleophilic addition of two Au(I)Cl units. In the present study, (HPd@Au) was successfully converted to unprecedented trimetallic (HPd@MAu) superatoms (M = Ag, Cu) by controlled doping of two Ag(I)Cl or Cu(I)Cl units, respectively. Single-crystal X-ray diffraction analysis demonstrated that two Ag(I) or Cu(I) ions were regioselectively incorporated.

Hydride-Mediated Controlled Growth of a Bimetallic (Pd@Au) Superatom to a Hydride-Doped (HPd@Au) Superatom.

A hydride (H)-doped bimetallic superatom (HPdAu) was produced by reacting BH with an oblate (PdAu) superatom protected by PPh. The H atom in (HPdAu) survived during the sequential addition of Au(I)Cl to form an (HPdAu) superatom, in sharp contrast to the proton release from a H-doped pure gold superatom (HAu) in the growth process to (Au). Single-crystal X-ray diffraction analysis and density functional theory calculations on (HPdAu) showed that the interstitially doped H atom induced a notable deformation of the core.

Hydride-Doped Gold Superatom (AuH): Synthesis, Structure, and Transformation.

Doping of a hydride (H) into an oblate-shaped gold cluster [Au(PPh)] was observed for the first time by mass spectrometry and NMR spectroscopy. Density functional theory calculations for the product [AuH(PPh)] demonstrated that the (AuH) core can be viewed as a nearly spherical superatom with a closed electronic shell. The hydride-doped superatom (AuH) was successfully converted to the well-known superatom Au, providing a new atomically precise synthesis of Au clusters via a bottom-up approach.