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A structurally precise hydride-containing Pt-doped Cu-rich nanocluster [PtH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 (CCPh) 6 ] (1) has been synthesized. It consists of a bicapped icosahedral Cu 14 cage that encapsulates a linear PtH 2 unit. Upon the addition of two equivalents of CF 3 COOH to 1, two hydrido clusters are isolated. These clusters are [PtHCu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 4 ] (2), which is a vertex-missing Cu 11 cuboctahedron encaging a PtH moiety, and [PtH 2 Cu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 3 ] (3), a distorted 3,3,4,4,4-pentacapped trigonal prismatic Cu 11 cage enclosing a PtH 2 unit. The electronic structure of 2, analyzed by Density Functional Theory, is a 2e superatom. The electrocatalytic activities of 1-3 for hydrogen evolution reaction (HER) were compared. Notably, Cluster 2 exhibited an exceptionally excellent HER activity within metal nanoclusters, with an onset potential of -0.03 V (at 10 mA cm -2 ), a Tafel slope of 39 mV dec -1 , and consistent HER activity throughout 3000 cycles in 0.5 M H 2 SO 4 . Our study suggests that the accessible central Pt site plays a crucial role in the remarkable HER activity and may provide valuable insights for establishing correlations between catalyst structure and HER activity., (© 2023 Wiley-VCH GmbH.)

The first 8-electron Pd/Ag superatomic alloys with an interstitial hydride [PdHAg 19 (dtp) 12 ] (dtp=S 2 P(O i Pr) 2 - ) 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., (© 2023 Wiley-VCH GmbH.)

The first hydride-containing 2-electron palladium/copper alloys, [PdHCu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 4 ] (PdHCu 11 ) and [PdHCu 12 {S 2 P(O i Pr) 2 } 5 {S 2 PO(O i Pr)} (C≡CPh) 4 ] (PdHCu 12 ), are synthesized from the reaction of [PdH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 6 ] (PdH 2 Cu 14 ) with trifluoroacetic acid (TFA). X-ray diffraction reveals that the PdHCu 11 and PdHCu 12 kernels consist of a central PdH unit encapsulated within a vertex-missing Cu 11 cuboctahedron and complete Cu 12 cuboctahedron, respectively. DFT calculations indicate that both PdHCu 11 and PdHCu 12 can be considered as axially-distorted 2-electron superatoms. PdHCu 11 shows excellent HER activity, unprecedented within metal nanoclusters, with an onset potential of -0.05 V (at 10 mA cm -2 ), a Tafel slope of 40 mV dec -1 , and consistent HER activity during 1000 cycles in 0.5 M H 2 SO 4 . Our study suggests that the accessible central Pd site is the key to HER activity and may provide guidelines for correlating catalyst structures and HER activity., (© 2023 Wiley-VCH GmbH.)

In sharp contrast to surface hydrides, reactivities of interstitial hydrides are difficult to explore. When treated with a metal ion (Cu + , Ag + , and Au + ), the stable Cu I dihydride template [Cu 11 H 2 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 ] (H 2 Cu 11 ) generates surprisingly three very different compounds, namely [CuH 2 Cu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 ] + (1), [AgH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 ((C≡CPh) 6 ] + (2), and [AuCu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 Cl] (3). Compounds 1 and 2 are both M I species and maintain the same number of hydride ligands as their H 2 Cu 11 precursor. Neutron diffraction revealed the first time a trigonal-pyramidal hydride coordination mode in the AgCu 3 environment of 2. 3 has no hydride and exhibits a mixed-valent [AuCu 11 ] 10+ metal core, making it a two-electron superatom., (© 2021 Wiley-VCH GmbH.)

Highly reactive copper-dihydride clusters, [Cu 15 (H) 2 (S 2 CNR 2 ) 6 (C 2 Ph) 6 ](PF 6 ) {R = n Bu (1 H ), n Pr (2 H ), i Bu (3 H )}, are isolated during the reaction of [Cu 28 H 15 {S 2 CN n Bu 2 } 12 ](PF 6 ) with ten equivalents of phenylacetylene. They are found to be intermediates in the formation of the earlier reported two-electron superatom [Cu 13 (S 2 CNR 2 ) 6 (C 2 Ph) 4 ] + . Better yields are obtained by reacting dithiocarbamate sodium salts, [Cu(CH 3 CN) 4 ](PF 6 ), BH 4 - and phenylacetylene. The presence of two hydrides in the isolated clusters is confirmed by the synthesis and characterization of its deuteride analogue [Cu 15 (D) 2 (S 2 CNR 2 ) 6 (C 2 Ph) 6 ] + , and a single-crystal neutron structure of 2 H . Structural characterization of 1 H reveals a new bicapped icosahedral copper(I) cage encapsulating a linear copper dihydride (CuH 2 ) - unit. Reaction of 3 H with Au(I) salts yields a highly luminescent [AuCu 12 (S 2 CN i Bu 2 ) 6 (C 2 Ph) 4 ] + cluster., (© 2020 Wiley-VCH GmbH.)

Rational syntheses under controllable reducing conditions in the preparation of superatoms with cluster electron number not exceeding two are challenging. Herein a dithiolate-stabilized two-electron silver nanocluster, Ag 10 {S 2 P(O i Pr) 2 } 8 (1), is isolated via a self-redox reaction of Ag 7 (H){S 2 P(O i Pr) 2 } 6 without adding extra reducing agents. The metal framework of Ag 7 , a bicapped trigonal bipyramid, is highly correlated to that of Ag 10 , suggesting Ag 7 (H){S 2 P(O i Pr) 2 } 6 acts as both reducing agent and template in cluster growth. 1 is highly fluorescent at ambient temperature and TD-DFT calculations indicate that the emission is of 1P x →1S nature., (© 2021 Wiley-VCH GmbH.)

Although atomically precise polyhydrido copper nanoclusters are of prime interest for a variety of applications, they have so far remained scarce. Herein, this work describes the synthesis of a dithiophosphate-protected copper(I) hydride-rich nanocluster (NC), [Cu 30 H 18 {S 2 P(OnPr) 2 } 12 ] (1 H ), fully characterized by various spectroscopic methods and single-crystal X-ray diffraction. The X-ray structure of 1 H reveals an unprecedented central Cu 12 hollow icosahedron. Six faces of this icosahedron are capped by Cu 3 triangles, the whole Cu 30 core being wrapped by twelve dithiophosphate ligands and the whole cluster has ideal S 6 symmetry. The locations of the 18 hydrides in 1 H were ascertained by a single-crystal neutron diffraction study. They are composed of three types: capping μ 3 -H, interstitial μ 4 -H (seesaw) and μ 5 -H ligands (square pyramidal), in good agreement with the DFT simulations. The numbers of hydrides and ligand resonances in the 1 H NMR spectrum of 1 H are in line with their coordination environment in the solid state, retaining the S 6 symmetry in solution. Furthermore, two new Se-protected polyhydrido copper nanoclusters, [Cu 30 H 18 {Se 2 P(OR) 2 } 12 ] (2 H : R=iPr 3 H : R=iBu) were synthesized from their sulfur relative 1 H via ligand displacement reaction and their X-ray structures feature the exceptional case where both the NC shape and size are fully conserved during the course of ligand exchange. DFT and TD-DFT calculations allow understanding the bonding and optical properties of clusters 1 H -3 H . In addition, the reaction of 1 H with [Pd(PPh 3 ) 2 Cl 2 ] in the presence of terminal alkynes led to the formation of new bimetallic Cu-Pd alloy clusters [PdCu 14 H 2 {S 2 P(OnPr) 2 } 6 (C≡CR) 6 ] (4: R=Ph; 5: R=C 6 H 4 F)., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The structurally precise Cu-rich hydride nanoclusters [PdCu 14 H 2 (dtc/dtp) 6 (C≡CPh) 6 ] (dtc: di-butyldithiocarbamate (1); dtp: di-isopropyl dithiophosphate (2)) were synthesized from the reaction of polyhydrido copper clusters [Cu 28 H 15 (S 2 CN n Bu 2 ) 12 ] + or [Cu 20 H 11 {S 2 P(O i Pr) 2 } 9 ] with phenyl acetylene in the presence of Pd(PPh 3 ) 2 Cl 2 . Their structures and compositions were determined by single-crystal X-ray diffraction and the results supported by ESI-mass spectrometry. Hydride positions in 1 were confirmed by single-crystal neutron diffraction. Each hydride is connected to one Pd 0 and four Cu I atoms in slightly distorted trigonalbipyramidal geometry. The anatomies of clusters 1 and 2 are very similar and DFT calculations allow rationalizing the interactions between the encapsulated [PdH 2 ] 2- unit and its Cu 14 bicapped icosahedral cage. As a result, Pd has the highest coordination number (14) so far recorded., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)