Rhombicuboctahedral Ag100: Four-Layered Octahedral Silver Nanocluster Adopting the Russian Nesting Doll Model

Precise atomic structure of metal nanoclusters (NCs) is fundamental for elucidating the structure–property relationships and the inherent size-evolution principles. Reported here is the largest known FCC-based (FCC=face centered cubic) silver nanocluster, [Ag₁₀₀(SC₆H₃^3,4F₂)₄₈(PPh₃)₈]⁻: the first all-octahedral symmetric nesting Ag nanocluster with a four-layered Ag₆@Ag₃₈@Ag₄₈S₂₄@Ag₈S₂₄P₈ structure, consistent symmetry elements, and a unique rhombicuboctahedral morphology distinct from theoretical predictions and previously reported FCC-based Ag clusters. DFT studies revealed extensive interlayer interactions and degenerate frontier orbitals. The FCC-based Russian nesting doll model constitutes a new platform for the study of the size-evolution principles of Ag NCs.     

A Sodalite‐Type Silver Orthophosphate Cluster in a Globular Silver Nanocluster

The synthesis and structure of a giant 102‐silver‐atom nanocluster (NC) 1 is presented. X‐ray structural analysis reveals that 1 features a multi‐shelled metallic core of Ag₆@Ag₂₄@Ag₆₀@Ag₁₂. An octahedral Ag₆ core is encaged by a truncated octahedral Ag₂₄ shell. The Ag₂₄ shell is composed of a hitherto unknown sodalite‐type silver orthophosphate cluster (SOC) {(Ag₃PO₄)₈}, reminiscent of the Ag₃PO₄ photocatalyst. The SOC is capped by six interstitial sulfur atoms, giving a unique anionic cluster [Ag₆@{(Ag₃PO₄)₈}S₆]^6?, which functions as an intricate polyhedral template with abundant surface O and S atoms guiding the formation of a rare rhombicosidodecahedral Ag₆₀ shell. An array of 6 linear Ag₂ staples further surround this Ag₆₀ shell. [Ag₆@{(Ag₃PO₄)₈}S₆]^6? is an unusual Ag‐based templating anion to induce the assembly of a SOC within silver NC. This finding provides molecular models for bulk Ag₃PO₄, and offers a fresh template strategy for the synthesis of silver NCs with high symmetry.     

A Functionalized Ag2S Molecular Architecture: Facile Assembly of the Atomically Precise Ferrocene‐Decorated Nanocluster [Ag74S19(dppp)6(fc(C{O}OCH2CH2S)2)18]

A ferrocene‐based dithiol 1,1′‐[fc(C{O}OCH₂CH₂SH)₂] has been prepared and treated with a Ag^I salt to form the stable dithiolate compound [fc(C{O}OCH₂CH₂SAg)₂]_n (fc=[Fe(η⁵‐C₅H₄)₂]). This is used as a reagent for the preparation of the nanocluster [Ag₇₄S₁₉(dppp)₆(fc(C{O}OCH₂CH₂S)₂)₁₈] which was obtained in good yield (dppp=1,3‐bis(diphenylphosphino)propane).     

On‐Top π‐Stacking of Quasiplanar Molecules in Hole‐Transporting Materials: Inducing Anisotropic Carrier Mobility in Amorphous Films

Dimers of partially oxygen‐bridged triarylamines were designed and synthesized as hole‐transporting materials. X‐ray structural analyses revealed that these compounds form on‐top π‐stacking aggregates in the crystalline state. TRMC measurements showed that high levels of anisotropic charge transport were induced in the direction of the π‐stacking. Surprisingly, even in vacuum‐deposited amorphous films, these compounds retained some of the face‐on π‐stacking, thus facilitating an out‐of‐plane carrier mobility.     

Face-Centered-Cubic Ag Nanoclusters: Origins and Consequences of the High Structural Regularity Elucidated by Density Functional Theory Calculations

Face-centered-cubic (FCC) silver nanoclusters (NCs) adopting either cubic or half-cubic growth modes have been recently reported, but the origin of these atomic assembly patterns and how they are achieved, which would inform our understanding of larger FCC silver nanomaterials, are both unknown. In this study, the cubic and half-cubic growth modes have been unified based on common structural characteristics, and differentiated depending on the starting blocks (cubic vs. half cubic). In both categories, the silver atoms adopt octahedral Ag₆, linear AgS₂ (in projection drawing), or tetrahedral AgS₃P binding modes, and the sulfur atoms adopt T-shaped SAg₃ and orthogonal SAg₄ modes. An additional T-shaped AgS₃ mode is oriented on the surface edge in cubic NCs to complete the cubic framework. Density functional theory calculations indicated that the high structural regularity originates from the strong diffusing capacity of the Ag(5d) and S(3p) orbitals, and the angular momentum distribution of the formed superatomic orbitals. The equatorial orientation of μ⁴-S or μ⁴-Ag determines whether growth stops or continues. In particular, a density-of-states analysis indicated that the octahedral silver atoms are chemically more reactive than the silver atoms in the AgS₃P motif, regardless of whether the parent NC functions as an electron donor or acceptor.     

A Precoordination Complex of 1,2,3‐Trimethyl‐1,3,5‐triazacyclohexane with tert‐Butyllithium as Key Intermediate in Its Methylene Group Deprotonation

α‐Lithiated tertiary methylamines are important building blocks in all fields of chemistry, such as for the synthesis of new ligand or catalyst systems. However, the access to these compounds is still limited and the reaction mechanism, in general, not fully understood. We present herein X‐ray diffraction analyses of organolithium compounds with 1,2,3‐trimethyl‐1,3,5‐triazacyclohexane ( 1 ), such as a precoordination adduct of tert‐butyllithium, [(tBuLi)₃?C₆H₁₅N₃], which represents a potential intermediate of the lithiation of the methylene group of this ligand. By means of molecular structures and computational studies, the regioselectivity of this deprotonation reaction can be understood. Furthermore, the tBuLi adduct gives a hint to an alternative deaggregation process of organolithium compounds.     

Formation of an Alkynyl‐Protected Ag112 Silver Nanocluster as Promoted by Chloride Released In Situ from CH2Cl2

By directly reducing alkynyl–silver precursors, we successfully obtained a large alkynyl‐protected silver nanocluster, (C₇H₁₇ClN)₃[Ag₁₁₂Cl₆(C≡CAr)₅₁], which is hitherto the largest structurally characterized silver nanocluster in the alkynyl family. The cluster exhibits four concentric core–shell structures (Ag₁₃@Ag₄₂@Ag₄₈@Ag₉), and four types of alkynyl–silver binding modes are observed. Chloride was found to be critical for the stabilization and formation of the silver nanocluster. The release of chloride ions in situ from CH₂Cl₂ solvent has been confirmed by mass spectrometry. This study suggests that the combination of alkynyl and halide ligands will pave a new way for the synthesis of large silver nanoclusters.     

Rational Design of the Metal‐Free KBe2BO3F2⋅(KBBF) Family Member C(NH2)3SO3F with Ultraviolet Optical Nonlinearity

The first fluorosulfonic ultraviolet (UV) nonlinear optical (NLO) material, C(NH₂)₃SO₃F, is rationally designed by taking KBe₂BO₃F₂ (KBBF) as the parent compound. C(NH₂)₃SO₃F features similar topological layers as KBBF by replacing inorganic (BO₃)^3? with organic C(NH₂)₃⁺ trigonal units and BeO₃F with SO₃F^? tetrahedra. Therefore, C(NH₂)₃SO₃F is a metal‐free UV NLO crystal. Benefiting from the coplanar configuration of the C(NH₂)₃⁺ cationic groups, it possesses a large SHG response of 5×KDP and moderate birefringence of 0.133@1064 nm. Besides, it has a short UV cutoff edge of 200 nm. The calculated results reveal the shortest SHG phase‐matching wavelengths can reach 200 nm. These findings highlight the exploration of metal‐free compounds as nontoxic and low‐cost UV NLO materials as a new research area.     

Pyrene‐Based Y‐shaped Solid‐State Blue Emitters: Synthesis,Characterization, and Photoluminescence

A series of pyrene‐based Y‐shaped blue emitters, namely, 7‐tert‐butyl‐1,3‐diarylpyrenes 4 were synthesized by the Suzuki cross‐coupling reaction of 7‐tert‐butyl‐1,3‐dibromopyrene with a variety of p‐substituted phenylboronic acids in good to excellent yields. These compounds were fully characterized by X‐ray crystallography, UV/Vis absorption and fluorescence spectroscopy, DFT calculations, thermogravimetric analysis, and differential scanning calorimetry. Single‐crystal X‐ray analysis revealed that the Y‐shaped arylpyrenes exhibited a low degree of π stacking owing to the steric effect of the bulky tert‐butyl group in the pyrene ring at the 7‐position, and thus, the intermolecular π–π interactions were effectively suppressed in the solid state. Despite the significantly twisted nonplanar structures, these molecules still displayed efficient intramolecular charge‐transfer emissions with clear solvatochromic shifts on increasing solvent polarity. An intriguing fact is that all of these molecules show highly blue emissions with excellent quantum yields in the solid state. Additionally, the two compounds containing the strongest electron‐accepting groups, CN ( 4d ) and CHO ( 4f ), possess high thermal stability, which, together with their excellent solid‐state fluorescence efficiency, makes them promising potential blue emitters in organic light‐emitting device applications.     

3,4,5‐Trinitropyrazole‐Based Energetic Salts

High‐density energetic salts that are comprised of nitrogen‐rich cations and the 3,4,5‐trinitropyrazolate anion were synthesized in high yield by neutralization or metathesis reactions. The resulting salts were fully characterized by ¹H, ¹³C NMR, and IR spectroscopy; differential scanning calorimetry; and elemental analysis. Additionally, the structures of the 3,5‐diaminotriazolium and triaminoguanidinium 3,4,5‐trinitropyrazolates were confirmed by single‐crystal X‐ray diffraction. Based on the measured densities and calculated heats of formation, the detonation performances (pressure: 23.74–31.89 GPa; velocity: 7586–8543 ms^?1; Cheetah 5.0) of the 3,4,5‐trinitropyrazolate salts are comparable with 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB; 31.15 GPa and 8114 ms^?1). Impact sensitivities were determined to be no less than 35 J by hammer tests, which places these salts in the insensitive class.     

Atom‐Precise Polyoxometalate–Ag2S Core–Shell Nanoparticles

Atomically precise polyoxometalate–Ag₂S core–shell nanoparticles were generated in a top‐down approach under solvothermal conditions and structurally confirmed by X‐ray single‐crystal diffraction as an interesting core–shell structure comprising an in situ generated Mo₆O₂₂^8? polyoxometalate core and a mango‐like Ag₅₈S₃₈ shell. This result demonstrates the possibility to integrate polyoxometalate and Ag₂S nanoparticles into a core–shell heteronanostructure with precisely controlled atomical compositions of both core and shell.     

Acid–Base‐Triggered Structural Transformation of a Polyoxometalate Core Inside a Dodecahedrane‐like Silver Thiolate Shell

Self‐assembly of metavanadate and organosilver(I) salts leads to a novel dodecahedrane‐like [Ag₃₀(^tBuS)₂₀]¹⁰⁺ silver(I) thiolate nanocage that tightly wraps an unusual C_2h polyoxovanadate anion. The polyoxovanadate core undergoes transformation to a D_3d configuration upon acidification, and reverts back to its original C_2h structure upon addition of base. Chromism was observed for the silver(I) thiolate cluster during the configurational change of the central polyoxovanadate core; the color of the solution changes reversibly from green to dark yellow. This work represents the first reported example of chromic polyoxometalate‐templated silver(I) thiolate shells that respond to external acid–base stimuli. It also represents an important advance in providing crystallographic proof that structural transformations occur in a nanoscale core–shell cluster.     

Structure Determination of Alkynyl‐Protected Gold Nanocluster Au22(tBuC≡C)18 and Its Thermochromic Luminescence

An alkynyl‐protected gold nanocluster, Au₂₂(^tBuC≡C)₁₈ ( 1 ), has been synthesized and its structure has been determined by single‐crystal X‐ray diffraction. The molecular structure consists of a Au₁₃ cuboctahedron kernel and three [Au₃(^tBuC≡C)₄] trimeric staples. The cluster 1 has strong luminescence in the solid state with a 15 % quantum yield, and it displays interesting thermochromic luminescence as revealed by temperature‐dependent emission spectra. The enhanced room‐temperature emission is characterized as thermally activated delayed fluorescence.     

Template‐Free Preparation of Volvox‐like CdxZn1−xS Nanospheres with Cubic Phase for Efficient Photocatalytic Hydrogen Production

Volvox‐like Cd_xZn_1?xS solid solutions with a cubic zinc blend structure were synthesized through a template‐free ethylene glycol process. Cd(Ac)₂ ? 2 H₂O, Zn(Ac)₂ ? 2 H₂O, and thiourea are used as the starting materials and dissolved in ethylene glycol. These reaction precursors and solvent not only contributed to control over the formation of the volvox‐like spherical geometry, but also exerted vigorous domination for existence of cubic‐phase Cd_xZn_1?xS nanostructures. As‐prepared volvox‐like Cd_xZn_1?xS nanospheres have a diameter of around 100 nm with extensional shells. These samples show excellent photocatalytic H₂ evolution activity from water splitting under visible‐light irradiation without any cocatalyst or scaffolding, owing to their tunable band gap, cubic zinc blend structure, and unique hierarchical porous structure with a high surface area (as high as 95.2 m² g^?1).