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.     

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.     

Observation of Non‐FCC Copper in Alkynyl‐Protected Cu53 Nanoclusters

The only feasible access to non‐face‐centered cubic (FCC) copper was by physical vapor deposition under high vacuum. Now, non‐FCC copper is observed in a series of alkynyl‐protected Cu₅₃ nanoclusters (NCs) obtained from solution‐phase synthesis. Determined by single‐crystal X‐ray crystallography, the structures of Cu₅₃(C≡CPhPh)₉(dppp)₆Cl₃(NO₃)₉ and its two derivatives reveal an ABABC stacking sequence involving 41 Cu atoms. It can be regarded as a mixed FCC and HCP structure, which gives strong evidence that Cu can be arranged in non‐FCC lattice at ambient conditions when proper ligands are provided. Characterization methods including X‐ray absorption fine structure, XPS, ESI‐MS, UV/Vis, Auger spectroscopy, and DFT calculations were carried out. Cu^II was shown to successively coordinate with introduced ligands and changed to Cu^I after bonding with phosphine. The following addition of NaBH₄ and the aging step further reduced it to the Cu₅₃ NC.     

Destructive effect of solar light on morphology of colloidal silver nanocubes

Colloidal silver nanocubes (NCs) were successfully synthesized by reduction of silver nitrate with ethylene glycol and polyvinylpyrrolidon as capping agent. The effect of solar light irradiation on the formation and morphology of silver NCs was investigated. Moreover, altering the amount of sodium sulfide was used to control the morphology and shape of primary silver seeds. Scanning electron microscopy, transmitting electron microscopy, X-ray diffraction and UV-vis spectroscopy were used to characterize silver NCs. The samples prepared under the solar light irradiation do not possess cubic shape while highly monodispersed silver NCs were obtained in dark room conditions. For dark room synthesis, a decrease of the amount of Na₂S by only 10 μL resulted in formation of mixture of silver nanospheres and nanowires in addition to NCs instead of the monodispersed silver NCs. However, similar increase of the amount of sodium sulfide results in distortion of cubic geometry of particles. The results suggest that solar light has a negative effect on the shape evolution of the primary silver seeds.     

Observation of Non-FCC Copper in Alkynyl-Protected Cu53 Nanoclusters

The only feasible access to non-face-centered cubic (FCC) copper was by physical vapor deposition under high vacuum. Now, non-FCC copper is observed in a series of alkynyl-protected Cu₅₃ nanoclusters (NCs) obtained from solution-phase synthesis. Determined by single-crystal X-ray crystallography, the structures of Cu₅₃(C≡CPhPh)₉(dppp)₆Cl₃(NO₃)₉ and its two derivatives reveal an ABABC stacking sequence involving 41 Cu atoms. It can be regarded as a mixed FCC and HCP structure, which gives strong evidence that Cu can be arranged in non-FCC lattice at ambient conditions when proper ligands are provided. Characterization methods including X-ray absorption fine structure, XPS, ESI-MS, UV/Vis, Auger spectroscopy, and DFT calculations were carried out. Cu^II was shown to successively coordinate with introduced ligands and changed to Cu^I after bonding with phosphine. The following addition of NaBH₄ and the aging step further reduced it to the Cu₅₃ NC.     

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.     

The Crystal Structure of Solvent‐Free Silver Dodecachloro‐closo‐dodecaborate Ag2[B12Cl12] from Aqueous Solution

Colourless octahedral single crystals of solvent‐free Ag₂[B₁₂Cl₁₂] (cubic, Pa3¯; a = 1238.32(7) pm, Z = 4) are obtained by the metathesis reaction of Cs₂[B₁₂Cl₁₂] with an aqueous solution of silver nitrate (AgNO₃) and recrystallization of the crude product from water. The crystal structure is best described as a distorted anti‐CaF₂‐type arrangement in which the quasi‐icosahedral [B₁₂Cl₁₂]^2— anions (d(B—B) = d(B—Cl) = 177—180 pm) are arranged in a cubic closest‐packed fashion. The tetrahedral interstices are filled with Ag⁺ cations which are strongly displaced from their ideal positions. Thereby each silver atom gets coordinated by six chlorine atoms from the edges of three [B₁₂Cl₁₂]^2— anions providing a distorted octahedral coordination sphere to the Ag⁺ cations (d(Ag—Cl) = 283—285 pm, CN = 6).     

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 novel one‐dimensional silver cylinder stabilized by mixed 2‐mercaptobenzoic acid and ethylenediamine ligands

A novel infinite one‐dimensional silver cylinder, namely poly[μ‐ethylenediamine‐μ₅‐(2‐sulfanidylbenzoato)‐μ₄‐(2‐sulfanidylbenzoato)‐tetrasilver(I)], [Ag₄(C₇H₄O₂S)₂(C₂H₈N₂)]_n, has been synthesized by one‐pot reaction of equivalent molar silver nitrate and 2‐mercaptobenzoic acid (H₂mba) in the presence of ethylenediamine (eda). One Ag atom is located in an AgS₂NO four‐coordinated tetrahedral geometry, two other Ag atoms are in an AgS₂O three‐coordinated T‐shaped geometry and the fourth Ag atom is in an AgSNO coordination environment. The two mba ligands show two different binding modes. The μ₂‐N:N′‐eda ligand, acting as a bridge, combines with mba ligands to extend the Ag^I ions into a one‐dimensional silver cylinder incorporating abundant Ag...Ag interactions ranging from 2.9298 (11) to 3.2165 (13) Å. Interchain N—H...O hydrogen bonds extend the one‐dimensional cylinder into an undulating two‐dimensional sheet, which is further packed into a three‐dimensional supramolecular framework by van der Waals interactions; no π–π interactions were observed in the crystal structure.     

Electro-active silver oxide nanocubes for label free direct sensing of bisphenol A to assure water quality

This research, for the first time, demonstrates a direct electrochemical detection of bisphenol A (BPA) using silver oxide (Ag₂O) nanocubes (NCs) modified platinum electrode. The Ag₂O NCs, size ranging from 60 to 100 nm utilized in this research as a smart electro-active sensing platform were pure and synthesized using a cost-effective, affordable, and facile chemical route. The Ag₂O NCs modified electrochemical sensor exhibited a low limit of detection (LOD) as 20 nmol dm^?3, high sensitivity as 95 μA (μmol dm^?3)^?1 cm^?2, and linear dynamic range (LDR) varies from 80 nmol dm^?3- 4.8 μmol dm^?3. This sensor also showed good selectivity, reproducibility, and reusability for BPA detection. The practical application of developed sensor was also tested using real water samples. The outcomes of this research suggested that Ag₂O NCs based sensor can be useful for effective and efficient electrochemical BPA sensing in both real and lab samples.     

Crystal structure of the monoclinic and cubic polymorphs of BiMn7O12

The complex perovskite BiMn₇O₁₂ occurs with two polymorphic structures, cubic and monoclinic. Currently their crystal structures are investigated with high-resolution synchrotron powder X-ray diffraction at room temperature. Rietveld analysis reveals unusual behavior for, respectively, the oxygen and bismuth atoms in the monoclinic and cubic phases. Bond valence calculations indicate that all the Mn atoms in both the phases are in trivalent state. Possible roles of the 6s² lone-pair electrons of Bi³⁺ in BiMn₇O₁₂ are discussed in comparison with the LaMn₇O₁₂ phase that is isomorphic to monoclinic BiMn₇O₁₂. Multiple roles of the lone-pair electrons are revealed, causing (i) A-site cation deficiency, (ii) octahedral tilting, (iii) A-site cation displacement, and (iv) Mn³⁺ Jahn-Teller (JT) distortion. Relationships between the monoclinic and cubic phases are discussed with emphasis on the MnO₂ and MnO₆ local structural aspects. All Mn atoms in the monoclinic polymorph have distorted coordination consistent with JT-active Mn(III) high spin, whereas for the cubic polymorph, the B-site Mn atoms show regular octahedral coordination.     

Synthesis of Lead‐free CsGeI3 Perovskite Colloidal Nanocrystals and Electron Beam‐induced Transformations

Colloidal nanocrystals (NCs) of metal halide perovskite have recently aroused great research interest, due to their remarkable optical and electronic properties. We report a solution synthesis of a new member in this category, that is, all‐inorganic lead‐free cesium germanium iodine (CsGeI₃) perovskite NCs. These CsGeI₃ colloidal NCs are confirmed to adopt a rhombohedral structure. Moreover, the electron beam‐induced transformations of these lead‐free perovskite NCs have been investigated for the first time. The fracture of single‐crystalline CsGeI₃ nanocubes occurs first, followed by the emergence and growth of cesium iodine (CsI) single crystals and the final fragmentation into small debris with random orientations. Notably, the electron‐reduced Ge species in CsGeI₃ nanocubes exhibit a distinctive transformation path, compared to heavier Pb atoms in lead halide perovskite NCs.     

Novel Copper(I) Clusters with 2‐(Diphenylphosphanyl)anilide Ligands. Synthesis and Crystal Structures of [Cu6X2(NHR)4] (X = Cl,Br, I; R = C6H4‐2‐PPh2)

Treatment of copper(I) halides CuX (X = Cl, Br, I) with lithium 2‐(diphenylphosphanyl)anilide [Li(HL)] in THF led to the formation of hexanuclear copper(I) complexes [Cu₆X₂(HL)₄] [X = Cl ( 1 ), Br ( 2 ), I ( 3 )]. In compounds 1 – 3 , the copper atoms are in a distorted octahedral arrangement and the amide ligands adopt a μ₃‐κP,κ²N bridging mode. Additionally there are two μ₂‐bridging halide ligands. Each of the [Cu₆X₂(HL)₄] clusters comprises two copper atoms, which are surrounded by two amide nitrogen atoms in an almost linear coordination [Cu–N: 186.2(3)–188.0(3) pm] and four copper atoms, which are connected to an amide N atom, a P atom, and a halogen atom in a distorted trigonal planar fashion [Cu–N: 199.6(3)–202.3(3) pm)].     

Synthesis,crystal structure and silver complexation of a novel saddle-shaped stilbenophane: NMR and theoretical study on the complex

A new Z,Z-stilbenophane was synthesised and characterised. According to an X-ray structure analysis, the structure has a saddle shape, with the π-electrons of the double bonds and the oxygen atoms pointing towards the centre of a cavity. The ligand forms a 1:1 complex with Ag⁺. Both NMR spectra and theoretical analysis (Gauge-independent atomic orbitals (GIAO) and Quantum theory of atoms in molecules (QTAIM)) suggest that the silver cation is bound within the molecular cavity. The metal is coordinated by the two olefinic double bonds and the four oxygen atoms in an approximately octahedral environment. The coordination motif is unusual because the soft silver cation prefers the interaction with the four hard oxygen atoms over the bonding to the arene units, which is frequently observed in Ag⁺ arene complexes.     

An Unprecedented Trinuclear Nickel(II) Complex Assembled from an Asymmetric Salamo-Type Ligand

An unprecedented trinuclear Ni(II) complex assembled from an asymmetric Salamo-type ligand 6-ethoxy- 4′,6′-dichloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol (H₂L) is synthesized. The Ni(II) complex with the general formula [Ni₃(L)₂(μ₃-OAc)₂]·3CH₃CN is characterized by IR, UV-vis, and fluorescence spectra and the single crystal X-ray analysis. All the Ni(II) atoms are hexacoordinated with slightly distorted octahedral symmetries. Interestingly, each Ni(II) atom is not located on the N₂O₂ cavity of the asymmetric Salamo-type (L)^2– unit, and two μ₃-OAc ions adopt an uncommon μ₃-η²:η¹ binding mode connecting the Ni1, Ni2, and Ni3 atoms. Furthermore, the crystallizing acetonitrile molecules successfully assemble into an infinite 2D network by hydrogen bonding and C–H···π interactions.     

A tetrahedrally coordinated AgI and NiII complex with a two‐dimensional framework containing one‐dimensional helical chains

The title complex, poly[bis(μ₆‐pyridine‐2,6‐dicarboxylato N‐oxide)nickel(II)disilver(I)], [Ag₂Ni(C₇H₃NO₅)₂]_n or [Ag₂Ni(pydco)₂]_n (H₂pydco = pyridine‐2,6‐dicarboxylic acid N‐oxide), has a two‐dimensional sheet structure. The two carboxylate groups adopt two coordination modes. The Ni^II ion displays a distorted octahedral geometry, bonded to two carboxylate O atoms of two different pydco ligands and four O donors from another two ligands, i.e. two carboxylate O atoms and two N‐oxide O atoms. The Ag^I ion adopts a tetrahedral coordination, linked by three O atoms of three different carboxylate groups and an N‐oxide O atom.     

Crystal structure of a silver(I) complex {[Ag(N-methylthiourea)2]NO3}n exhibiting infinite chains of AgS4 tetrahedra

A polymeric silver(I) complex, bis(N-methylthiourea)silver(I) nitrate, {[Ag(Metu)₂]NO₃} _n is prepared and its crystal structure is determined. The compound crystallizes in the monoclinic C2/c space group. In the structure, distorted AgS₄ tetrahedra are linked through the sulfur atoms of the Metu ligand to form isolated infinite chains of the type [Ag(SR)₂] _n ⁿ⁺. The cationic chains are separated from each other by nitrate ions that do not coordinate to the metal ion. The chains are bridged via N-H...O hydrogen bonds involving the nitrate ions. The complex exhibits an Ag—Ag separation of ∼3.21 ? indicating the existence of significant argentophilic interactions. An upfield shift in the >C=S resonance of Metu in ¹³C NMR and downfield shift in the N-H resonance in ¹H NMR are consistent with sulfur coordination to silver(I).     

All-Metallic Zn=Zn Double-π Bonded Octahedral Zn2M4 (M=Li,Na) Clusters with Negative Oxidation State of Zinc

Zn=Zn double bonded-especially double-π bonded-systems are scarce due to strong Coulomb repulsion caused by the Zn atom's internally crowded d electrons and very high energy of the virtual π orbitals in Zn₂ fragments. It is also rare for Zn atoms to exhibit negative oxidation states within reported Zn−Zn bonded complexes. Herein, we report Zn=Zn double-π bonded octahedral clusters Zn₂M₄ (M=Li, Na) bridged by four alkali metal ligands, in which the central Zn atom is in a negative oxidation state. Especially in D_4h−Zn₂Na₄, the natural population analysis shows that the charge of the Zn atom reaches up to −0.89 |e| (−1.11 |e| for AIM charge). Although this cooperation inevitably increases the repulsion between two Zn atoms, the introduction of the s¹-type ligands results in occupation of degenerated π orbitals and the electrons being delocalized over the whole octahedral framework as well, in turn stabilizing the octahedral molecular structure. This study demonstrates that maintaining the degeneracy of the π orbitals and introducing electrons from equatorial plane are effective means to construct double-π bonds between transitional metals.     

Pseudocontact contribution to the isotropic chemical shifts of protons in octahedral paramagnetic complex ions

Following the formalism of Kurland and McGarvey, it is shown that transferred spin densities onto ligands can give rise to pseudocontact shifts even for protons in octahedral complexes. In the case of ammonia as a ligand the pseudocontact shift of the protons originates from the spin density on the p orbitals of the nitrogen as well as spin density on the s orbitals on the neighboring hydrogen atoms. Using LCAO-MO wavefunctions for the Ru(NH₃)³⁺₆ ion the contact and pseudocontact shifts were estimated to contribute about 75% and 25% of the total shift of the amine protons respectively. Based on experimental paramagnetic NMR shifts, the covalency parameter in the Ru(NH₃)³⁺₆ ion was recalculated to be λ = 0.325.     

Synthesis,Structure, and Physical Properties of a Barium Complex with 5‐Sulfoisophthalic Acid Sodium Salt

The complex [Ba₃(sip)₂(H₂O)₉] · H₂O ( 1 ) (NaH₂sip = 5‐sulfoisophthalic acid sodium) was synthesized and characterized by single‐crystal X‐ray diffraction. Structural determination reveals that the asymmetric unit in 1 contains two crystallographically independent Ba^II atoms. The Ba1 atom is eight‐coordinate with distorted monocapped pentagonal bipyramidal arrangement, whereas the Ba2 atom is ten‐coordinated with bicapped tetragonal prismatic arrangement. The two carboxylate groups of sip^3– adopt different coordination modes, μ₂‐η¹:η¹‐bridging, and μ₂‐η²:η¹‐bridging. The sulfonate group coordinates to three different Ba^II atoms in a tridentate μ₃ mode to generate a ladder‐like one‐dimensional chain. The chains are connected by μ₂‐η¹:η¹‐bridging carboxylate groups to form a wave‐like two‐dimensional network, which are further linked by sip^3– anions to generate a three‐dimensional structure. The thermal stability and luminescence properties of complex 1 were also investigated.