An Inherently Chiral Au₂₄ Framework with Double‐Helical Hexagold Strands

Abstract

2,3-bis(diphenylphosphino)butane enantiomers (chiraphos,L )u sed as chiral auxiliaries results in the preferential formation of an unprecedented Au 24 framework with inherent chirality.T he crystal structure of [Au 24 L 6 Cl 4 ] 2+ (1)h as as quare antiprism-like octagold core twinned by two helicene-like hexagold motifs,w here the inherent chirality is associated with the helical arrangement. The clusters carrying (R,R)-and (S,S)-diphosphines had right-and left-handed strands,respectively.Circular dichroism spectra showed peaks in the visible to near-IR region, some of which did not coincide with absorption bands,s uggesting the enantiomeric Au 24 frameworks possess unique chiroptical properties.T he Au 24 frameworks were thermally robust, which could be attributed to the superatomic concept (18 e À system) and the steric constraint effects of the bridging ligand units.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A reasonable approach for the generation of hollow icosahedral kernels in metal nanoclusters

“…1c, highlighted in yellow); in contrast, the Ag atoms in light blue links outward SR ligands (highlighted in red) on M 40 -S3. (ii) M 44 (SR) 30 (M = Au/Ag/Cu; SR = SPhCl 2 ): the Au 12 Ag 32 (SR) 30 nanocluster is adopted to analyze the structure of M 44 (SR) 30 58 . Au 12 Ag 32 (SR) 30 also has a three-shell configuration: Au 12 (M 44 -S1)@Ag 20 (M 44 -S2)@6*Ag 2 (SR) 5 (M 44 -S3).…”

“…etal nanoclusters are an emerging class of modular nanomaterials [1][2][3][4][5][6] , and have been sparking great research interests owing to their atomically precise structures and intriguing properties . The physiochemical properties of these nanomaterials, such as chirality, luminescence, catalysis, magnetism, and electrochemistry, can be rationalized in terms of their quantum size effect as well as discrete electronic states [28][29][30][31][32][33][34][35][36][37][38] . Besides, the atomically precise nature of these modular nanomaterials is of the most interestindeed, compared with large-sized nanoparticles, nanoclusters (typically <2 nm of the metallic kernel) present more precise compositions/constructions, and thus allow for the atomic-level elucidation of structural evolutions and structure-property correlations [1][2][3][4][5][6][39][40][41][42][43][44][45][46] .…”

“…Of all reported nanoclusters with precise structures, the icosahedral configuration is the most typical, which is frequently observed in both metal kernels and ligand shells of nanoclusters [47][48][49][50][51] . Interestingly, except for the non-hollow icosahedral M 1 @M 12 kernel (M represents the metal), the hollow icosahedral M 12 kernel has also served as a basic nano-building block of nanoclusters (e.g., Ag 44 (SR) 30 , Au 12+n Cu 32 (SR) 30+n , Ag 50 (dppm) 6 (SR) 30 , Au 144 (SR) 60 , etc.) 10,11,[52][53][54][55][56] .…”

“…In this work, based on the Au-alloying-induced nanocluster transformation from M 40 (SR) 24 to M 44 (SR) 30 (M = Au/Ag/Cu), a reasonable avenue for the generation of hollow icosahedral M 12 kernels has been mapped out, i.e., the kernel collapse from several small nano-building blocks to an integrated hollow icosahedron. The proposed avenue might serve as a common approach in constructing metallic kernels of nanoclusters and nanoparticles (not limited to the M 12 structure).…”

Revealing the chirality origin and homochirality crystallization of Ag14 nanocluster at the molecular level

“…hirality is ubiquitous in (supra)molecular structures, such as DNA in living organisms and natural products in plants, which plays a pivotal role in biological activity, catalysis, medicines, and a variety of other applications 1,2 . Although the enantioselective preparation and separation of chiral small molecules induced by chiral reagents have been well established, the realization of this process with achiral reagents still faces great challenges, especially for these higher-order motifs such as nanoclusters, nanoparticles, and supramolecules [3][4][5][6][7][8][9][10][11][12][13][14] . Recent research on the origin of chirality formed in achiral systems has led to great advances in chiral metal nanoclusters protected by achiral ligands; the origin of chirality of them has been typically classified into three types: (1) chiral arrangement of inner metal core atoms; 15,16 (2) asymmetric arrangement of surface structure to form a chiral shell; [17][18][19][20][21] (3) distortion or rotation induced structure chirality [22][23][24] .…”