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A gold(I)‐cluster‐based twin‐cage has been constructed by post‐clustering covalent modification of a hexa‐aldehyde cluster precursor with triaminotriethylamines. The cages‐on‐cluster structure has double cavities and four binding sites, which show site‐discriminative binding for silver(I) and copper(I) guests. The guests in the tripodal hats affect the luminescence of the cluster: the tetra‐silver(I) host–guest complex is weakly red‐emissive, while the bis‐copper(I)‐bis‐silver(I) one is non‐emissive but is a stimuli‐responsive supramolecule. The copper(I) ion inside the tri‐imine cavity is oxidation sensitive, which enables the release of the bright emissive precursor cluster triggered by H2O2 solution. The hybridization of a cluster with cavities to construct a cluster‐based cage presents an innovative concept for functional cluster design, and the post‐clustering covalent modification opens up new avenues for finely tuning the properties of clusters. [ABSTRACT FROM AUTHOR]

We report the structures, stability and catalysis properties of two Ag21 nanoclusters, namely [Ag21(H2BTCA)3(O2PPh2)6]SbF6 (1) and [Ag21(C≡CC6H3‐3,5‐R2)6(O2PPh2)10]SbF6 (2) (H4BTCA=p‐tert‐butylthiacalix[4]arene, R=OMe). Both Ag21 structures possess an identical icosahedral kernel that is surrounded by eight peripheral Ag atoms. Single‐crystal structural analysis and ESI‐MS revealed that 1 is an 8‐electron cluster and 2 has four free electrons. Theoretical results show that the P‐symmetry orbitals are found as HOMO‐1 and HOMO states in 1, and the frontier unoccupied molecular orbitals (LUMO, LUMO+1 and LUMO+2) show D‐character, indicating 1 is a superatomic cluster with an electronically closed shell 1S21P6, while 2 has an incomplete shell configuration 1S21P2. These two Ag21 clusters show superior stability under ambient conditions, and 1 is robust even at 90 °C in toluene and under oxidative conditions (30 % H2O2). Significantly, 2 exhibits much higher activity than 1 as catalyst in the reduction of 4‐nitrophenol. This work demonstrates that ligands can influence the electronic structures of silver clusters, and further affect their stability and catalytic performance. [ABSTRACT FROM AUTHOR]

Intensely luminescent coinage metal cluster [Au12Ag14(C≡CPh)20(mdppz)4(CH3OH)8](BF4)6 { 1, mdppz = 2-(3-methylpyrazinyl)diphenylphosphine} was synthesized and structurally characterized. Twenty alkynyl ligands (PhC≡C-), four mdppz ligands, and eight methanol molecules were found to co-stabilize the metal cluster. Interestingly, when the weakly ligated methanol molecules were removed, the green luminescence of 1 significantly redshifted to yellow; exposing the resulting yellow sample in methanol vapor immediately restores the green luminescence. Thus reversible luminescence response can be observed by removing and restoring methanol. Other small solvent molecules with weak coordination ability such as Me2CO, MeCN, and C2H5OH were also found to be good agents to trigger the vapochromism. [ABSTRACT FROM AUTHOR]

An intensely luminescent gold(I)-silver(I) cluster [(C)(AuPPhpy2)6Ag6(CF3CO2)3](BF4)5 (PPhpy2=bis(2-pyridyl)phenylphosphine) ( 3) is synthesized by the reaction of [(C)(AuPPhpy2)6Ag4](BF4)6 with AgCF3CO2. All eight faces of the octahedral C@Au6 core in 3 are capped, that is, six faces are capped by silver ions and two by tetrafluoroborates. Cluster 3 is intensely luminescent in solution with a quantum yield of 92 %. Ligation of CF3CO2− ions is vital for the construction and emission properties of 3, as confirmed by DFT calculations. BF4− ions are involved in the protecting sphere of the metal core, as evidenced by 19F NMR data. The participation of phosphines, CF3CO2−, and BF4− ions in the protection of the emissive core and the enhancement of the rigidity of the cluster result in the high emission efficiency. This is the first example of organic ligands and inorganic anions forming a rigid protecting sphere for luminescent coinage-metal clusters. [ABSTRACT FROM AUTHOR]

A gold(i)–silver(i) cluster bearing six carboxylate groups has been synthesized through the oxidation of its aldehyde precursor and the Au6 core of this cluster displays an octahedral or a trigonal prismatic configuration depending on the crystallization conditions. The reversible interconversion between these two isomers can be triggered in the solid state by the addition or removal of acetonitrile solvent molecules. Interestingly, luminescence changes were observed as each configuration shows different emission colors, yellow for octahedral type and red for the trigonal prismatic one. [ABSTRACT FROM AUTHOR]

The first silver cluster encapsulating an organic anion―squarate dianion―has been synthesized. Two C4O42− anions arranged in a staggered sandwich type arrangement are confined in the Ag24 cage. The incorporation of squarate anions into the silver alkynyl system leads to the red shift of absorption of the cluster in comparison to silver squarate. [ABSTRACT FROM AUTHOR]

A silver alkynyl cluster containing a Ag70 shell and two lacunary [PW9O34]9− templating ions was synthesized by an ionothermal approach. Fast core–shell electronic communication between silver(i) centers and polyoxometalates was verified via cyclic voltammetry studies in [BMIm]BF4. [ABSTRACT FROM AUTHOR]

Surface organic ligands are critical in determining the formation and properties of atomically precise metal nanoclusters. In contrast to the conventionally used thiolate, phosphine and alkynyl ligands, the amine ligand dipyridylamine is applied here as a protecting agent in the synthesis of atomically precise metal nanoclusters. We report two homoleptic amido-protected Ag nanoclusters as examples of all-nitrogen-donor-protected metal nanoclusters: [Ag21(dpa)12]SbF6 (Ag21) and [Ag22(dpa)12](SbF6)2 (Ag22) (dpa = dipyridylamido). Single crystal X-ray structural analysis reveals that both clusters consist of a centered-icosahedron Ag13 core wrapped by 12 dpa ligands. The flexible arrangement of the N donors in dpa facilitates the solvent-triggered reversible interconversion between Ag21 and Ag22 due to their very different solubility. The successful use of dpa in the synthesis of well-defined silver nanoclusters may motivate more studies on metal nanoclusters protected by amido type ligands. Noble metal nanoclusters are commonly protected by thiolate, phosphine, or alkynyl ligands. Here, the authors synthesize two homoleptic amido-protected silver clusters, whose structures interconvert easily with changes of solvent due to the coordination flexibility and diverse binding modes of the nitrogen-donor ligands. [ABSTRACT FROM AUTHOR]

Small anions play a big role in the preparation of an intensely luminescent gold(I)–silver(I) cluster. In their Communication on page 7117 ff. Q.‐M. Wang and co‐workers show that the stepwise addition of silver ions to the gold‐cluster precursor enhances the rigidity of the cluster. The emissive core is fully protected by organic ligands and inorganic anions, which results in high emission efficiency. [ABSTRACT FROM AUTHOR]

The article presents a study on the synthesis, structure, and photophysical properties of a heteronuclear gold(I)-silver(I) cluster that is emissive in solution at room temperature. It notes that the report is the first regarding the luminescence from a gold(I) carbonium system. It cites the findings of the single crystal x-ray structural analysis on the cationic part of the complexes. It mentions that complex 2 is brightly emissive while complex 3 is soluble in polar solvents like chloroform.

Review: 40 refs. [ABSTRACT FROM AUTHOR]

Abstract: The phosphorescent silver(I)–gold(I) cluster complex [CAu6Ag2(dppy)6](BF4)4 (N1) selectively stains the nucleolus, with a much lower uptake in the nucleus and cytoplasm, and exhibits excellent photostability. This Ag–Au cluster, which has a photoluminescent lifetime of microseconds, is particularly attractive as a probe in applications of time-gated microscopy. Investigation of the pathway of cellular entry indicated that N1 permeates the outer membrane and nuclear membrane of living cells through an energy-dependent and non-endocytic route within 10 min. High concentrations of N1 in the nucleolus have been quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and transmission electron microscopy coupled with an energy dispersive X-ray analysis (TEM-EDXA), which also helped to elucidate the mechanism of the specific staining. Intracellular selective staining may be correlated with the microenvironment of the nucleolus, which is consistent with experiments conducted at different phases of the cell cycle. These results prove that N1 is a very attractive phosphorescent staining reagent for visualizing the nucleolus of living cells. [Copyright &y& Elsevier]