Tiara-like Hexanuclear Nickel-Platinum Alloy Nanocluster

Tiara-like metal nanoclusters (TNCs) have attracted a great deal of attention because of their high stability and easy synthesis under atmospheric conditions as well as their high activity in various catalytic reactions. Alloying is one of the methods that can be used to control the physicochemical properties of nanoclusters, but few studies have reported on alloy TNCs. In this study, we synthesized alloy TNCs [NixPt6-x(PET)12, where x = 1-5 and PET = 2-phenylethanethiolate] consisting of thiolate, nickel (Ni), and platinum (Pt). We further evaluated the stability, geometric structure, and electronic structure by high-performance liquid chromatography and density functional theory calculations. The results revealed that NixPt6-x(PET)12 has a distorted structure and is therefore less stable than single-metal TNCs.

Improved activity for the oxygen evolution reaction using a tiara-like thiolate-protected nickel nanocluster

Practical electrochemical water splitting and carbon-dioxide reduction are desirable for a sustainable energy society. In particular, facilitating the oxygen evolution reaction (OER, the reaction at the anode) will increase the efficiency of these reactions. Nickel (Ni) compounds are excellent OER catalysts under basic conditions, and atomically precise Ni clusters have been actively studied to understand their complex reaction mechanisms. In this study, we evaluated the geometric/electronic structure of tiara-like metal nanoclusters [Ni_n(PET)_2n; n = 4, 5, 6, where PET refers to phenylethanethiolate] with the same SR ligand. The geometric structure of Ni₅(SR)₁₀ was determined for the first time using single-crystal X-ray diffraction. Additionally, combined electrochemical measurements and X-ray absorption fine structure measurements revealed that Ni₅(SR)₁₀ easily forms an OER intermediate and therefore exhibits a high specific activity.

Cavity Size Effect on Host-Guest Property of Tiara-like Structural Mn(SR)2n Nanoclusters Probed by NMR Spectroscopy

The lack of detect technology hinders the understanding of host-guest (H-G) chemical properties for thiolate-protected tiara-like structural nanoclusters (Mn(SR)2n). In this work, NMR spectroscopy is demonstrated as a powerful tool to probe the H-G structure of Mn(SR)2n both experimentally and theoretically. A low-field shifting and wide chemical shift (CS) signal of the H nucleus in CH2Cl2 is observed in the NMR spectrum of the mixture of CH2Cl2 and Pd8(PET)16 (PET is 2-phenylethanethiol), agreeing with the theoretical results that a deshielding area appears in the central cavity of Pd8(SR)16. All Mn(SR)2n own similar nucleus-independent chemical shift maps and deshielding cavities, which means that the H nucleus in small molecules trapped by Mn(SR)2n should have consistent low-field shifted CSs. However, such a phenomenon was only observed in the NMR spectrum of the mixed solution of Pd8(SR)16 and CH2Cl2, indicating that Pd8(SR)16 is the only one in the series of Pdn(SR)2n (n = 4~16) analogues that can capture a CH2Cl2, the H-G properties of Mn(SR)2n are highly dependent on their cavity sizes, and a guest molecule only inserts into the matching cavity of Mn(SR)2n. We anticipate that the realization of such convenient probe strategy will give a deeper understanding of the H-G properties of Mn(SR)2n.

Observable but Not Isolable: The RhAu24 (PET)181+ Nanocluster

The synthesis and characterization of RhAu₂₄ (PET)₁₈ (PET = 2-phenylethanethiol) is described. The cluster is cosynthesized with Au₂₅ (PET)₁₈ and rhodium thiolates in a coreduction of RhCl₃ , HAuCl₄ , and PET. Rapid decomposition of RhAu₂₄ (PET)₁₈ occurs when purified from the other reaction products, precluding the study of isolated cluster. Mixtures containing RhAu₂₄ (PET)₁₈ , Au₂₅ (PET)₁₈ , and rhodium thiolates are therefore characterized. Mass spectrometry, X-ray photoelectron spectroscopy, and chromatography methods suggest a combination of charge-charge and metallophilic interactions among Au₂₅ (PET)₁₈^1- , rhodium thiolates and RhAu₂₄ (PET)₁₈ resulting in stabilization of RhAu₂₄ (PET)₁₈ . The charge of RhAu₂₄ (PET)₁₈ is assigned as 1+ on the basis of its stoichiometric 1:1 presence with anionic Au₂₅ (PET)₁₈ , and its stability is contextualized within the superatom electron counting rules. This analysis concludes that the Rh atom absorbs one superatomic electron to close its d-shell, giving RhAu₂₄ (PET)₁₈¹⁺ a superatomic electron configuration of 1S² 1P⁴ . Overall, an updated framework for rationalizing open d-shell heterometal dopant electronics in thiolated gold nanoclusters emerges.

Crystal structures of 9-[bis-(benzyl-sulfan-yl)meth-yl]anthracene and of cyclo-dodeca-kis-(μ2-phenyl-methane-thiol-ato-κ2 S:S)hexa-palladium(6 Pd-Pd)-anthracene-9,10-dione (1/1)

The first title compound, C29H24S2, L1, represents an example of an anthracene-based functionalized di-thio-ether, which may be useful as a potential chelating or terminal ligand for coordination chemistry. This di-thio-acetal L1 crystallizes in the monoclinic space group P21/c. The phenyl rings of the benzyl groups and that of the anthracene unit form dihedral angles of 49.21 (4) and 58.79 (5)° and the crystal structure displays short C-H⋯π contacts. Surprisingly, when attempting to coordinate L1 to [PdCl2(PhCN)2], instead of the targeted chelate complex [PdCl2(κ2-L1)], a cleavage reaction leads to the formation of the centrosymmetric hexa-nuclear cyclic cluster of composition [Pd6(μ2-SCH2Ph)12] Pd6, or [Pd6(C7H7S)12]·C14H8O2. This tiara-shaped hexa-mer crystallizing in the triclinic space group P consists of six approximately square planar Pd(II)S4 centers, which are inter-connected through twelve μ2-bridging benzyl thiol-ate groups. The Pd⋯Pd contacts range from 3.0892 (2) to 3.1609 (2) Å and can be considered as weakly bonding. The unit cell of Pd6 contains also a co-crystallized anthracene-9,10-dione mol-ecule.

Co-synthesis of atomically precise nickel nanoclusters and the pseudo-optical gap of Ni4(SR)8

For Ni_n(SR)_2n, electrochemical gaps reflect their HOMO–LUMO gaps more accurately.