Syntheses,Characterization and X‐ray Structure of the First Silver(I) Complexes with 4‐Amino‐3‐thioxo‐3,4‐dihydro‐1,2,4‐triazin‐5(2H)‐one

Reaction of thiocarbohydrazide with glyoxolic acid monohydrate led to 4‐amino‐3‐thioxo‐3,4‐dihydro‐1,2,4‐triazin‐5(2H)‐one (AHTTO, 1 ). Treatment of 1 with AgNO₃ and PPh₃ gave thecomplexes [(PPh₃)₂Ag₂(μ‐N,S‐AHTTO)₂](NO₃)₂ ( 2 ) and [(PPh₃)₂Ag(AHTTO)]NO₃ · MeOH ( 3 ) was obtained under different conditions. All the compounds have been characterized by elemental analyses, IR spectroscopy and X‐ray diffraction studies.     

A Silver Nanocluster Containing Interstitial Sulfur and Unprecedented Chemical Bonds

The emergence of thiolated metal nanoclusters provides opportunities to identify significant and unprecedented phenomena because they are at quantum sizes and can be characterized with X‐ray crystallography. Recently silver nanoclusters have received extensive interest owing to their merits, such as low‐cost and rich properties. Herein, a thiolated silver nanocluster [Ag₄₆S₇(SPhMe₂)₂₄]NO₃ (Ag₄₆ for short) with a face‐centered cubic (fcc) structure was successfully synthesized and structurally resolved by X‐ray analysis. Most importantly, interstitial sulfur was found in the lattice void of Ag₄₆ without lattice distortion or expansion, indicating that the classic theory of interstitial metal solid solutions might be not applicable at quantum size. Furthermore, unprecedented chemical bonds and unique structural features (such as asymmetrically coordinated μ₄‐S) were found in Ag₄₆ and might be related to the interstitial sulfur, which is supported by natural population analyses.     

Elucidating the Doping Effect on the Electronic Structure of Thiolate‐Protected Silver Superatoms by Photoelectron Spectroscopy

Gas‐phase photoelectron spectroscopy (PES) was conducted on [XAg₂₄(SPhMe₂)₁₈]^? (X=Ag, Au) and [YAg₂₄(SPhMe₂)₁₈]^2? (Y=Pd, Pt), which have a formal superatomic core (X@Ag₁₂)⁵⁺ or (Y@Ag₁₂)⁴⁺ with icosahedral symmetry. PES results show that superatomic orbitals in the (Au@Ag₁₂)⁵⁺ core remain unshifted with respect to those in the (Ag@Ag₁₂)⁵⁺ core, whereas the orbitals in the (Y@Ag₁₂)⁴⁺ (Y = Pd, Pt) core shift up in energy by about 1.4 eV. The remarkable doping effect of a single Y atom (Y=Pd, Pt) on the electronic structure of the chemically modified (Ag@Ag₁₂)⁵⁺ superatom was reproduced by theoretical calculations on simplified model systems and was ascribed to 1) the weaker binding of valence electrons in Y@(Ag⁺)₁₂ compared to Ag⁺@(Ag⁺)₁₂ due to the reduction in formal charge of the core potential, and 2) the upward shift of the apparent vacuum level due to the presence of a repulsive Coulomb barrier between [YAg₂₄(SPhMe₂)₁₈]^? and electron.     

Synthesis, single crystal X-ray analysis, and TEM for a single-sized Au11 cluster stabilized by SR ligands: The interface between molecules and particles

An SR-modified Au cluster with a sub-nanometer size, Au₁₁(S-4-NC₅H₄)₃(PPh₃)₇ (1), has been synthesized by NaBH₄ reduction of Au(S-py)(PPh₃) or by reacting [Au₉(PPh₃)₈](NO₃)₃ with HS-4-py in good yield. Its molecular structure has been elucidated by single crystal X-ray diffraction, and TEM observation has been achieved for the first time for this size of SR-modified Au clusters. The core structure is best described in terms of an incomplete icosahedron. CV measurements in CH₂Cl₂ have suggested that the cluster does not coagulate in solution with significant concentration.     

Strategy for the Construction of Diverse Poly‐NHC‐Derived Assemblies and Their Photoinduced Transformations

A series of supramolecular assemblies of types [Ag₈( L )₄](PF₆)₈ and [Ag₄( L )₂](PF₆)₄, obtained from the tetraphenylethylene (TPE) bridged tetrakis(1,2,4‐triazolium) salts H₄‐L(PF₆)₄ and Ag^I ions, is described. The assembly type obtained dependends on the N‐wingtip substituents of H₄‐L(PF₆)₄. Changes in the lengths of the N4‐wingtip substituents enables controlled formation of assemblies with either [Ag₄( L )₂](PF₆)₄ or [Ag₈( L )₄](PF₆)₈ stoichiometry. The molecular structures of selected [Ag₈( L )₄](PF₆)₈ and [Ag₄( L )₂](PF₆)₄ assemblies were determined by X‐ray diffraction analyses. While H₄‐ L (PF₆)₄ does not exhibit fluorescence in solution, their tetra‐NHC (NHC=N‐heterocyclic carbene) assemblies do upon NHC–metal coordination. Upon irradiation, all assemblies undergo a light‐induced, supramolecule‐to‐supramolecule structural transformation by an oxidative photocyclization involving phenyl groups of the TPE core, resulting in a significant change of the luminescence properties.     

Kupferchalkogenid‐Clusterverbindungen mit nitro‐funktionalisierter Ligandenhülle

Copper Chalcogenide Cluster Compounds with Nitro‐functionalized Ligand Shell Three new copper chalcogenide cluster molecules, [Cu₄(SC₆H₄NO₂)₄(PPh₃)₄] ( 1 ), [Cu₄(SC₆H₄NO₂)₂(OAc)₂(PPh₃)₄] ( 2 ), and [Cu₂₂Se₆(SC₆H₄NO₂)₁₀(PPh₃)₈] ( 3 ), have been synthesized and characterized by single crystal X‐ray structure analysis. 1 and 2 were prepared from the reactions of Cu(OAc) and HSC₆H₄NO₂ in the presence of PPh₃ and have a similar “chair” structure in which two copper atoms are trigonally coordinated and two are tetrahedrally coordinated. The nitro groups of the ligands are not coordinated to any metal atom, but are located on the surface of the organic shell of the cluster molecules. In a further reaction between 2 and Se(SiMe₃)₂, cluster 3 was crystallized. Crystals of 3 include approximately 16.5 molecules THF per formula unit. This synthesis demonstrates the use of these “small” copper chalcogenide clusters as precursor compounds for the synthesis of bigger species. Non‐functionalized compounds similar to 1 and 2 are typically very pale or even colourless crystals. This is in contrast to the clusters presented in this work, which formed intensively orange or red crystals, due to the presence of the nitro groups. To investigate the influence of these nitro groups on the optical properties in more detail we have carried out UV‐VIS spectroscopic measurements.     

Alternating Array Stacking of Ag26Au and Ag24Au Nanoclusters

An assembly strategy for metal nanoclusters using electrostatic interactions with weak interactions, such as C?H???π and π???π interactions in which cationic [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ and anionic [Ag₂₄Au(2‐EBT)₁₈]^? nanoclusters gather and assemble in an unusual alternating array stacking structure is presented. [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? is a new compound type, a double nanocluster ion compound (DNIC). A single nanocluster ion compound (SNIC) [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? was also synthesized, having a k‐vector‐differential crystallographic arrangement. [PPh₄]⁺ [Ag₂₄Au(2,4‐DMBT)₁₈]^? adopts a different assembly mode from both [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? and [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^?. Thus, the striking packing differences of [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^?, [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? and the existing [PPh₄]⁺ [Ag₂₄Au(2,4‐DMBT)₁₈]^? from each other indicate the notable influence of ligands and counterions on the self‐assembly of nanoclusters.     

Metal‐Carbene‐Templated Photochemistry in Solution: A Universal Route towards Cyclobutane Derivatives

A series of dicarbene‐bridged metallacycles [Ag₂( 1 )₂](PF₆)₂, [Ag₂( 2 )₂](BF₄)₂, [Ag₂( 3 )₂](PF₆)₂, [Ag₂( 7 )₂](BF₄)₂, [Ag₂( 8 )₂](BF₄)₂ and [Ag₂( 11 )₂](PF₆)₂ were obtained in high yields via the reactions of 1,2,4‐triazole‐, 1,2,3‐triazole‐ and imidazo[1,5‐a]pyridine‐based ligands with Ag₂O in CH₃CN. The C=C double bonds in all of the newly synthesized metallacycles went through [2 + 2] photodimerization under UV irradiation condition (λ = 365 nm, T = 298 K) yielding the dinuclear rctt‐cyclobutane‐silver(I) complexes [Ag₂( 4 )](PF₆)₂, [Ag₂( 5 )](BF₄)₂, [Ag₂( 6 )](PF₆)₂, [Ag₂( 9 )](BF₄)₂, [Ag₂( 10 )](BF₄)₂ and [Ag₂( 12 )](PF₆)₂, respectively with quantitative yields. Treatment of the these cyclobutane‐bridged silver(I) complexes with NH₄Cl resulted in the exclusive formation of cyclobutane derivatives after removal of the silver(I) metal ions.     

The thermal motion of gold atoms in metal cluster compounds as determined by Mössbauer and specific heat

¹⁹⁷Au Mössbauer effect spectroscopy and specific heat measurements have been performed as a function of temperature on three gold polynuclear cluster compounds, [Au₉(PPh₃)₈](NO₃)₃, Au₁₁(PPh₃)₇(SCN)₃, and Au₅₅(PPh₃)₁₂Cl₆. The Mössbauer data yield information on the vibrational motions of the various distinguishable Au sites, as well as on the motion of the clusters as a whole. The Mössbauer and the specific heat data are successfully described by a superposition of inter- and intra-cluster vibrations. The latter are determined by calculating numerically the normal modes of vibration of the metal cores.     

Synthesis and Structures of Silver(I) Complexes of 4-Amino-3,5-dipropyl-4H-1,2,4-triazole and 4-Amino-3,5-dibutyl-4H-1,2,4-triazole: A Possible Mechanism of Formation of Ag4tz6 Cluster

Five silver(I) complex of 4-amino-3,5-dipropyl-4H-1,2,4-triazole (4-NH₂-3,5-Pr₂tz) or 4-amino-3,5-dibutyl-4H-1,2,4-triazole (4-NH₂-3,5-Bu₂tz), namely [Ag₂(4-NH₂-3,5-Bu₂tz)₂(NO₃)₂] (1), [Ag₄(4-NH₂-3,5-Pr₂tz)₆(NO₃)₂](NO₃)₂ (2), [Ag₄(4-NH₂-3,5-Pr₂tz)₆](ClO₄)₄ (3), [Ag₄(4-NH₂-3,5-Pr₂tz)₆](CF₃SO₃)₄ (4) and [Ag₄(4-NH₂-3,5-Bu₂tz)₆](BF₄)₄ (5), have been prepared and structurally characterized by X-ray single crystal diffractions. Based on the structural data, a possible mechanism for the formation of Ag₄tz₆ cluster has been proposed, involving the formation of a dimer of dimer—(Ag₂tz₂)₂, followed by the replacement of counterions by two additional triazoles.     

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.     

T-symmetric 40-nucleus silver clusters assembled by hetero-anions

We report two anion-templated Ag₄₀ clusters, [Ag₄₀(E)₄(SO₄){S₂P(OEt)₂}₂₄](PF₆)₆ (E = S, 1 ; Se, 2 ). The anionic templates were generated in situ from the decomposition of dithiophosphate (dtp) ligands. The extrusion of sulfur undergoes disproportionation reactions to generate sulfide and sulfate anions, which provide the source of templates in the subsequent cluster assembly reactions. Two Ag₄₀ clusters display high similarity in their structures. The sulfide (selenide) anions and the central sulfate anion reveal a six-coordinate and a rare dodecametallic dodecaconnective pattern, respectively. Four near-equivalent [Ag₁₀(E){S₂P(OEt)₂}₆]²⁺ motifs were assembled via the connection of central sulfate anion to construct Ag₄₀ clusters. The cluster cation, [Ag₄₀(E)₄(SO₄){S₂P(OEt)₂}₂₄]⁶⁺, displayed in T symmetry, is unprecedented in anion-templated silver clusters.     

Anion dependent formation of Ag(I) complexes of multidentate azine ligands: Synthesis and structural study

The extended structures of Ag-complexes of the azine based ligands phenyl-2-pyridyl ketone azine (L₁) and di-2-pyridyl ketone azine (L₂) are reported, and focus is made on the investigation of the influence of the anion and supramolecular interactions on the self-assembly. Using AgNO₃, AgClO₄ and CF₃COOAg salts as starting materials for both ligands in acetonitrile, we observed the formation of the dinuclear complexes [Ag₂(L₁)₂](NO₃)₂ (1a), [Ag₂(L₁)₂](ClO₄)₂ (1b), from L₁, the tetranuclear complexes [Ag₄(L₂)₂ (NO₃)(CH₃CN)₂](NO₃)₃ (2a), [Ag₄(L₂)₂(CF₃COO)₃CH₃CN](CF₃COO) (2b) and the linear chain polynuclear complex {[Ag₃(L₂)₂] (ClO₄)₃}_n (3) from L₂. The X-ray structures show that the molecular geometry depends on the choice of anion. The silver centers have distorted tetrahedral coordination geometry in all the complexes. Weak hydrogen bonding and other interactions result in 2-D and 3-D networks in these complexes.     

Strategy for the Construction of Diverse Poly-NHC-Derived Assemblies and Their Photoinduced Transformations

A series of supramolecular assemblies of types [Ag₈( L )₄](PF₆)₈ and [Ag₄( L )₂](PF₆)₄, obtained from the tetraphenylethylene (TPE) bridged tetrakis(1,2,4-triazolium) salts H₄-L(PF₆)₄ and Ag^I ions, is described. The assembly type obtained dependends on the N-wingtip substituents of H₄-L(PF₆)₄. Changes in the lengths of the N4-wingtip substituents enables controlled formation of assemblies with either [Ag₄( L )₂](PF₆)₄ or [Ag₈( L )₄](PF₆)₈ stoichiometry. The molecular structures of selected [Ag₈( L )₄](PF₆)₈ and [Ag₄( L )₂](PF₆)₄ assemblies were determined by X-ray diffraction analyses. While H₄- L (PF₆)₄ does not exhibit fluorescence in solution, their tetra-NHC (NHC=N-heterocyclic carbene) assemblies do upon NHC–metal coordination. Upon irradiation, all assemblies undergo a light-induced, supramolecule-to-supramolecule structural transformation by an oxidative photocyclization involving phenyl groups of the TPE core, resulting in a significant change of the luminescence properties.     

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.     

Synthesis, structure and characterization of binuclear silver(I) complexes

Summary Two binuclear Ag^I complexes, [{Ag(dppp)}₂](NO₃)₂ (1) and [{Ag(dppb)}₂(NO₃)]₂ (2) (dppp = Ph₂P(CH₂)₃PPh₂, dppb = Ph₂P(CH₂)₄PPh₂], were synthesized and characterized by elemental analysis, t.g., i.r. and ³¹P-n.m.r. spectra. Single crystals of complex (2) were obtained from MeOH-CHCl₃. The X-ray crystal structure shows that the dppb ligand is bidentate, with two ligands bridging two metal ions to form a centrosymmetric dimer.     

Hydrogen Bonding Network of 4‐Amidiniumpyridine Acetate and PtIIbis(triphenylphosphine) Complexes with 4‐Amidine­pyridine

The X‐ray structures of 4‐amidiniumpyridine acetate, ( 1· H)AcO, and of cis‐[Pt( 1 )₂(PPh₃)₂](NO₃)₂ ( 2 ), as well as their IR spectra, reveal intramolecular hydrogen bonding, which held together the cations and the anions. The IR spectroscopic data suggest that this may be so also in cis‐[PtCl( 1 )(PPh₃)₂](BF₄) ( 3 ). In ( 1· H)AcO and in 2 extensive intermolecular hydrogen bonding networks span through the whole crystals.     

Alkynyl-Protected Chiral Bimetallic Ag22Cu7 Superatom with Multiple Chirality Origins

Understanding the origin of chirality in the nanostructured materials is essential for chiroptical and catalytic applications. Here we report a chiral AgCu superatomic cluster, [Ag₂₂Cu₇(C≡CR)₁₆(PPh₃)₅Cl₆](PPh₄), Ag₂₂Cu₇ , protected by an achiral alkynyl ligand (HC≡CR: 3,5-bis(trifluoromethyl)phenylacetylene). Its crystal structure comprises a rare interpenetrating biicosahedral Ag₁₇Cu₂ core, which is stabilized by four different types of motifs: one Cu(C≡CR)₂, four −C≡CR, two chlorides and one helical Ag₅Cu₄(C≡CR)₁₀(PPh₃)₅Cl₄. Structural analysis reveals that Ag₂₂Cu₇ exhibits multiple chirality origins, including the metal core, the metal-ligand interface and the ligand layer. Furthermore, the circular dichroism spectra of R/S-Ag₂₂Cu₇ are obtained by employing appropriate chiral molecules as optical enrichment agents. DFT calculations show that Ag₂₂Cu₇ is an eight-electron superatom, confirm that the cluster is chirally active, and help to analyze the origins of the circular dichroism.     

Neue Silber‐Tellurid Cluster stabilisiert mit zweizähnigen Phosphanen: Synthese und Struktur von {[Ag5(TePh)6(Ph2P(CH2)2PPh3)](Ph2P(CH2)2PPh2)}∞, [Ag18Te(TePh)15(Ph2P(CH2)3PPh2)3Cl] und [Ag38Te13(TetBu)12(Ph2P(CH2)2PPh2)3]

Novel Silver‐Telluride Clusters Stabilised with Bidentate Phosphine Ligands: Synthesis and Structure of {[Ag₅(TePh)₆(Ph₂P(CH₂)₂PPh₃)](Ph₂P(CH₂)₂PPh₂)}_∞, [Ag₁₈Te(TePh)₁₅(Ph₂P(CH₂)₃PPh₂)₃Cl], and [Ag₃₈Te₁₃(Te t Bu)₁₂(Ph₂P(CH₂)₂PPh₂)₃] Bidentate phosphine ligands have been found effective to stabilise polynuclear cores containing silver and chalcogenide ligands. They can act as intra and intermolecular bridges between the silver centres. The clusters {[Ag₅(TePh)₆(Ph₂P(CH₂)₂PPh₃)](Ph₂P(CH₂)₂PPh₂)}_∞ ( 1 ), [Ag₁₈Te(TePh)₁₅(Ph₂P(CH₂)₃PPh₂)₃Cl] ( 2 ), and [Ag₃₈Te₁₃(TetBu)₁₂(Ph₂P(CH₂)₂PPh₂)₃] ( 3 ) have been prepared and their molecular structure determined. Compound 2 and 3 are molecular structures with separated cluster cores while 1 forms a polymeric chain bridged by phosphine ligands. ( 1 : space group P2₁/c (No. 14), Z = 4, a = 3518,1(7) pm, b = 2260,6(5) pm, c = 3522,1(7) pm, β = 119,19(3)°; 2 : space group R3 (No. 148), Z = 6, a = b = 3059,4(4) pm, c = 5278,8(9) pm; 3: space group Pccn (No. 56), Z = 4, a = 3613,0(9) pm, b = 3608,6(7) pm, c = 2153,5(8) pm)     

Octahedral and Cyclic [Ag6] Cluster Cores Stabilized by {Ag3(Spz)3(N‐triphos)3} Motifs [HSpz = Pyrazine‐2‐thiolate,N‐triphos = Tris((diphenylphosphanyl)methyl)amine]: Ag···Ag Interactions

The complexes [Ag₁₂(Spz)₁₂(N‐triphos)₂][Ag₃(Spz)₃(N‐triphos)]₂ · (DMF)₆ ( 1 ) and [Ag₁₈(Spz)₁₂(N‐triphos)₄(CF₃CO₂)₆] ( 2 ) were synthesized and structurally characterized by X‐ray diffraction [HSpz = pyrazine‐2‐thiolate, N‐triphos = tris((diphenylphosphanyl)methyl)amine]. The central [Ag₆] ring with chair‐conformation in 1 and the ideally octahedral [Ag₆] cluster core in 2 are both stabilized by the tripodal building units of neutral [Ag₃(Spz)₃(N‐triphos)] compound. The Ag ··· Ag distances of the [Ag₆] moieties in 1 and 2 are 3.07 and 2.81 Å, respectively, exhibiting intermetallic interactions, which can enhance the stability of [Ag₆] conformations. In addition, the π ··· π interactions between parallel pyrazine rings could impose on the building and the Ag ··· Ag interactions of these Ag–S clusters.