Unexpected structural transformation into noria-like Ag13 metal clusters and a copper-doping induced boost in photoluminescence

2020 ◽  
Vol 56 (35) ◽  
pp. 4789-4792 ◽  
Author(s):  
Su-Kao Peng ◽  
Zhou Lu ◽  
Mo Xie ◽  
Yong-Liang Huang ◽  
Dong Luo ◽  
...  
Keyword(s):  
Structural Transformation ◽  
Metal Clusters ◽  
Silver Clusters ◽  
Copper Doping ◽  
Emission Efficiency ◽  
Trinuclear Complexes ◽  
Cu Ions

We describe silver clusters which unexpectedly transform from cyclic trinuclear complexes and σ-donating phenylacetylene, featuring a noria-like conformation. The introduction of Cu ions leads to isomorphic clusters which boost emission efficiency.

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

scholarly journals Kinetic Versus Thermodynamic Metalation Enables Synthesis of Isostructural Homo- and Heterometallic Trinuclear Clusters

2020 ◽  
Author(s):  
Sung-Min Hyun ◽  
Apoorva Upadhyay ◽  
Anuvab Das ◽  
Corey Burns ◽  
Siyoung Sung ◽  
...  
Keyword(s):  
Cluster Expansion ◽  
Metal Clusters ◽  
Systematic Variation ◽  
Selective Synthesis ◽  
Temperature Dependent ◽  
Ion Content ◽  
Trinuclear Complexes ◽  
Trinuclear Clusters ◽  
Hexadentate Ligand ◽  
Programmed Assembly

Temperature-dependent metalation of the new hexadentate ligand (tris(5-(pyridin-2-yl)-1<i>H</i>-pyrrol-2-yl)methane; H<sub>3</sub>TPM) enables the selective synthesis of both mononuclear (<i>i.e. </i>Na(THF)<sub>4</sub>[Fe(TPM)], kinetic product) and trinuclear (<i>i.e.</i> Fe<sub>3</sub>(TPM)<sub>2</sub>, thermodynamic product) complexes. Exposure of Na(THF)<sub>4</sub>[Fe(TPM)] to FeCl<sub>2</sub> or ZnCl<sub>2</sub> triggers cluster expansion to generate homo- or heterometallic trinuclear complexes, respectively. The developed approach enables systematic variation of ion content in isostructural metal clusters via programmed assembly.

scholarly journals Kinetic Versus Thermodynamic Metalation Enables Synthesis of Isostructural Homo- and Heterometallic Trinuclear Clusters

2020 ◽  
Author(s):  
Sung-Min Hyun ◽  
Apoorva Upadhyay ◽  
Anuvab Das ◽  
Corey Burns ◽  
Siyoung Sung ◽  
...  
Keyword(s):  
Cluster Expansion ◽  
Metal Clusters ◽  
Systematic Variation ◽  
Selective Synthesis ◽  
Temperature Dependent ◽  
Ion Content ◽  
Trinuclear Complexes ◽  
Trinuclear Clusters ◽  
Hexadentate Ligand ◽  
Programmed Assembly

Temperature-dependent metalation of the new hexadentate ligand (tris(5-(pyridin-2-yl)-1<i>H</i>-pyrrol-2-yl)methane; H<sub>3</sub>TPM) enables the selective synthesis of both mononuclear (<i>i.e. </i>Na(THF)<sub>4</sub>[Fe(TPM)], kinetic product) and trinuclear (<i>i.e.</i> Fe<sub>3</sub>(TPM)<sub>2</sub>, thermodynamic product) complexes. Exposure of Na(THF)<sub>4</sub>[Fe(TPM)] to FeCl<sub>2</sub> or ZnCl<sub>2</sub> triggers cluster expansion to generate homo- or heterometallic trinuclear complexes, respectively. The developed approach enables systematic variation of ion content in isostructural metal clusters via programmed assembly.

Adsorption of O2 on anionic silver clusters: spins and electron binding energies dominate in the range up to nano sizes

2016 ◽  
Vol 18 (2) ◽  
pp. 743-748 ◽  
Author(s):  
Jun Ma ◽  
Xizi Cao ◽  
Xiaopeng Xing ◽  
Xuefeng Wang ◽  
Joel H. Parks
Keyword(s):  
Metal Clusters ◽  
Binding Energies ◽  
Important Task ◽  
Silver Clusters ◽  
Electron Binding Energies ◽  
Electron Binding

Exploring the reactivity of metal clusters is an important task in cluster science, while only a few previous studies involve the reactions of nano-sized ones.

Metal-insulator transitions in metal clusters: a high-energy spectroscopy study of palladium and silver clusters

1992 ◽  
Vol 96 (22) ◽  
pp. 8679-8682 ◽  
Author(s):  
V. Vijayakrishnan ◽  
A. Chainani ◽  
D. D. Sarma ◽  
C. N. R. Rao
Keyword(s):  
Metal Clusters ◽  
High Energy ◽  
Silver Clusters ◽  
Spectroscopy Study ◽  
Metal Insulator

Metal clusters in plasma polymer matrices Part II. Silver clusters

1999 ◽  
Vol 1 (18) ◽  
pp. 4447-4451 ◽  
Author(s):  
Dirk Salz ◽  
Ryszard Lamber ◽  
Michael Wark ◽  
Alfred Baalmann ◽  
Nils Jaeger
Keyword(s):  
Metal Clusters ◽  
Polymer Matrices ◽  
Plasma Polymer ◽  
Silver Clusters

The structure of pre-mRNA and mRNA from erythroid cells

1978 ◽  
Vol 36 (2) ◽  
pp. 234-235
Author(s):  
A.-M. Ladhoff ◽  
B.J. Thiele ◽  
Ch. Coutelle ◽  
S. Rosenthal
Keyword(s):  
Bone Marrow ◽  
Structural Transformation ◽  
Electron Micrographs ◽  
Ammonium Acetate ◽  
Bone Marrow Cells ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Ordered Structures ◽  
Rabbit Bone ◽  
Rabbit Reticulocytes

The suggested precursor-product relationship between the nuclear pre-mRNA and the cytoplasmic mRNA has created increased interest also in the structure of these RNA species. Previously we have been published electron micrographs of individual pre-mRNA molecules from erythroid cells. An intersting observation was the appearance of a contour, probably corresponding to higher ordered structures, on one end of 10 % of the pre-mRNA molecules from erythroid rabbit bone marrow cells (Fig. 1A). A virtual similar contour was observed in molecules of 9S globin mRNA from rabbit reticulocytes (Fig. 1B). A structural transformation in a linear contour occurs if the RNA is heated for 10 min to 90°C in the presence of 80 % formamide. This structural transformation is reversible when the denatured RNA is precipitated and redissolved in 0.2 M ammonium acetate.

Comparison of TEM and STM observations of small silver clusters on different carbon supports

1990 ◽  
Vol 48 (4) ◽  
pp. 264-265
Author(s):  
Bernd Tesche ◽  
Tobias Schilling
Keyword(s):  
Vibration Isolation ◽  
Pyrolytic Graphite ◽  
Carbon Film ◽  
Silver Clusters ◽  
Carbon Supports ◽  
Stacking Order ◽  
System P ◽  
High Resolution Tem ◽  
High Degree ◽  
Degree Of Order

The objective of our work is to determine:a) whether both of the imaging methods (TEM, STM) yield comparable data andb) which method is better suited for a reliable structure analysis of microclusters smaller than 1.5 nm, where a deviation of the bulk structure is expected.The silver was evaporated in a bell-jar system (p 10−5 pa) and deposited onto a 6 nm thick amorphous carbon film and a freshly cleaved highly oriented pyrolytic graphite (HOPG).The average deposited Ag thickness is 0.1 nm, controlled by a quartz crystal microbalance at a deposition rate of 0.02 nm/sec. The high resolution TEM investigations (100 kV) were executed by a hollow-cone illumination (HCI). For the STM investigations a commercial STM was used. With special vibration isolation we achieved a resolution of 0.06 nm (inserted diffraction image in Fig. 1c). The carbon film shows the remarkable reduction in noise by using HCI (Fig. 1a). The HOPG substrate (Fig. 1b), cleaved in sheets thinner than 30 nm for the TEM investigations, shows the typical arrangement of a nearly perfect stacking order and varying degrees of rotational disorder (i.e. artificial single crystals). The STM image (Fig. 1c) demonstrates the high degree of order in HOPG with atomic resolution.

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