4-
October 1999
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41 Reads
An exceptionally stable 1:2 complex [FeL(2)](3-) is formed from the ligand H(3)L and Fe(III). In contrast, the affinity of this ligand for other biometals is relatively small. These properties make H(3)L a highly promising candidate for medical applications (e.g. for the treatment of iron overload).
[In]
October 1999
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41 Reads
Near C(3) symmetry is displayed by the 19-atom In-P polyhedron that forms the central structural unit in the title compound (see structure), which was synthesized by reaction of InCl(3) with PEt(3) and PhP(SiMe(3))(2). In addition to In-P bonds, the cage has In-In and P-P bonds. Six terminal chloro ligands and three PEt(3) ligands surround the cluster core which itself encloses a central chloride anion.
[Al]
November 1999
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19 Reads
A "naked" aluminum atom links two aluminum tetrahedra in the [Al(7){N(SiMe(3))(2)}(6)](-) ion (see picture), which results from the reaction of a metastable AlCl solution with LiN(SiMe(3))(2) and crystallizes with [Li(OEt(2))(3)](+) as cation. This unique structure among molecular metal atom clusters represents a small but characteristic section of cubic close-packed aluminum.
Synthesis and Methane-Binding Properties of Disulfide-Linked Cryptophane-0.0.0
January 2012
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63 Reads
Into the crypt: Direct coupling of cyclotrithiophenolene gives a new class of cryptophane with labile disulfide linkages, which is the smallest cryptophane yet reported. The new cryptophane (see structure, S yellow, C gray, H light gray) is shown to bind methane or nitrogen in solution.
NMR Spectroscopic Detection of Protein Protons and Longitudinal Relaxation Rates between 0.01 and 50 MHz
May 2005
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33 Reads
(Graph Presented) Relaxation time: Direct profiles of protein 1H relaxation in D2O at mM concentrations were generated by NMR spectroscopy at 0.01-50 MHz (see picture). The study of lysozyme at pH 3.5 (monomeric) and pH 9.0 (dimeric), and of α-synuclein (unfolded), provides direct information on aggregation through estimates of the realignment correlation time and on the overall compactness of the protein.
Oriented Monolayer Film of Gd(2)O(3):0.05Eu Crystallites: Quasi-Topotactic Transformation of the Hydroxide Film and Drastic Enhancement of Photoluminescence Properties
May 2009
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46 Reads
Caught on film: A semitransparent and intensely luminescent monolayer film of oriented Gd(2)O(3):0.05 Eu platelet crystallites is fabricated by annealing the precursor hydroxide film (see scheme). The photoluminescence properties of the as-transformed film are greatly improved over those of the hydroxide film, and are much more pronounced than those of the corresponding Gd(2)O(3):0.05 Eu powder.
(C4N2H12)[FeII/(0.86)FeIII(1.14)(HPO3)1.39(HPO4)0.47(PO4)0.14F3]: a fluoro-phosphite-hydrogenphosphate-phosphate iron(II,III) mixed-valence organically templated compound
February 2004
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44 Reads
Ordnung im Chaos: Die antiferromagnetische Titelverbindung wurde unter milden Hydrothermalbedingungen synthetisiert und Mößbauer-spektroskopisch untersucht. Die Eisen(II)- und Eisen(III)-Kationen besetzen unterschiedliche kristallographische Positionen, während die Phosphit- und Hydrogenphosphat/Phosphat-Oxoanionen über zwei Phosphorlagen fehlgeordnet sind (siehe Struktur).
Synthesis of Perovskite-Based Porous La 0.75 Sr 0.25 MnO 3 Nanotubes as a Highly Efficient Electrocatalyst for Rechargeable Lithium-Oxygen Batteries
April 2013
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72 Reads
Tailoring an electrocatalyst: The synergistic effect of the high catalytic activity and the unique hollow channel structure of the perovskite-based porous La0.75 Sr0.25 MnO3 nanotube electrocatalyst endows the Li-O2 battery with a high specific capacity, superior rate capability, and good cycle stability.
A p-Type NiO-Based Dye-Sensitized Solar Cell with an Open-Circuit Voltage of 0.35 V
June 2009
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178 Reads
In tandem: Employing a molecular dyad and a cobalt-based electrolyte gives a threefold-increase in open-circuit voltage (V(OC)) for a p-type NiO device (V(OC) = 0.35 V), and a fourfold better energy conversion efficiency. Incorporating these improvements in a TiO(2)/NiO tandem dye-sensitized solar cell (TDSC), results in a TDSC with a V(OC) = 0.91 V (see figure; CB = conductance band, VB = valence band).
Nanocomposites with Structure Domains of 0.5 to 3 nm by Polymerization of Silicon Spiro Compounds
September 2009
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46 Reads
Two from one: It is possible to form two different, interpenetrating polymer structures-silicon dioxide and a phenolic resin-simultaneously in a single step without the formation of by-products by using a readily polymerizable, organic silicon spiro compound. This new polymerization process enables the fabrication of materials with domain sizes of 0.5 to 3 nm.
Reduction of a Metal-Organic Framework by an Organometallic Complex: Magnetic Properties and Structure of the Inclusion Compound [(η5-C5H5)2Co]0.5@MIL-47(V)
August 2010
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57 Reads
The stoichiometric reduction of the MIL-47(V) framework (see picture; green VO6 octahedra) was performed using cobaltocene as an organometallic reducing agent. The formation of a mixed-valence compound with a V3+/V4+ ratio of 1:1 was confirmed by magnetic susceptibility measurements. Incorporation of cobaltocene into the MIL-47(V) framework can be reversed upon treatment with water.
Na2.8Cu5Sn5.6: A Crystalline Alloy Featuring Intermetalloid (1)(infinity){Sn-0.6@Cu-5@Sn-5} Double-Walled Nanorods with Pseudo-Five-Fold Symmetry
February 2012
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46 Reads
Not quasi-crystalline: approximate five-fold symmetry appears in bronze-type Cu-Sn rods that are separated by Na atoms in Na(2.8)Cu(5)Sn(5.6). The rods are compared to the [Sn@Cu(12)@Sn(20)](12-) cluster in the recently characterized A(12)Cu(12)Sn(21) phases (A=Na-Cs), and a saltlike description in analogy to Zintl phases of p-block metals is introduced for these new polar intermetallic phases with a high d-block metal content.
The [closo-2-CB6H7]− Ion: The First Representative of the 7-Vertex Monocarbaborane Series This work was supported by the Alexander-von-Humboldt Stiftung (FRG) (B.Š.), Deutsche Forschungsgemeinschaft (B. W., O.L.T.), Fonds der Chemischen Industrie (B.W.), and the Ministry of Education of Czech Republic (Project LN00A028). We also thank the Grant Agency of the Charles University (Grant No. 203/00/B-CH/PřF) and the Supercomputing Center of the Charles University in Prague for computer time.
June 2002
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96 Reads
Opening up closo-cluster chemistry: The first representative of the seven-vertex closo monocarbaborane series, the [closo-2-CB 6H 7] - ion (see structure), was isolated together with the [closo-1-CB 7H 8] - ion from simple reactions between nido-1-CB 8H 12 and Et 3N. Both ions exhibit high stability in air and are potentially useful for weakly coordinating anion chemistry.
Massively Parallel Dip–Pen Nanolithography with 55 000-Pen Two-Dimensional Arrays
November 2006
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83 Reads
(Figure Presented) Lots of writing on the wall: A simple and flexible approach for performing high-throughput, large-area, direct-write molecular patterning, without tip feedback, is demonstrated by using a 55 000-pen two-dimensional array of atomic force microscope (AFM) cantilevers. The use of low-aspect-ratio pyramidal tips, curved cantilevers, and a novel gravity-driven alignment method allows parallel patterning of molecules across 1-cm2 substrate areas at sub-100-nm resolution.
Water Gas Shift Reaction on Cu and Au Nanoparticles Supported on CeO2(111) and ZnO(000): Intrinsic Activity and Importance of Support Interactions
February 2007
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478 Reads
A cerious contender: The catalytic activity in the water gas shift reaction of Au and Cu nanoparticles supported on CeO2(111) is superior to that of these nanoparticles on a ZnO(0001) support or of the bulk metals (the diagram shows the results depending on the Au nanoparticle coverage). These results illustrate the essential role that an oxide can have in the activity of supported Au nanocatalysts. (Graph Presented).
Acidic Water Monolayer on Ruthenium(0001)
December 2012
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27 Reads
Acidic water: The first monolayer of water on a Ru(0001) surface is anomalously acidic compared to bulk water, according to infrared and mass spectroscopic investigations of the water layer using ammonia as a probe for surface acidity. The observation suggests that acid-base chemistry may be quite different at the water-metal interfaces than in aqueous solution.
Catalytic Activity of Pt/TaB2(0001) for the Oxygen Reduction Reaction
April 2013
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54 Reads
A great film with special effects: An epitaxial Pt thin film with a thickness of 1.5 nm on a TaB2 (0001) substrate (see high-angle annular dark-field STEM image) was tested as an electrocatalyst for the oxygen reduction reaction. Its specific activity was twice that observed for polycrystalline Pt or Pt(111). Analysis and DFT calculations showed that the Pt layer is alloyed with Ta, the electronic effect of which on Pt leads to the enhanced activity.
Pt(II)-Catalyzed Intramolecular Reaction of Furans with Alkynes This work was supported by the DGICYT (project PB97-0002) and the MCyT (predoctoral fellowship to B.M.-M.). We also acknowledge Johnson Matthey PLC for a generous loan of PtCl(2).
January 2002
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10 Reads
Ein Platin-Cyclopropylcarben-Komplex, der, wie im Schema gezeigt, durch anti-Angriff eines Furanrestes an einen Platin-(η2-Alkin)-Komplex gebildet wird, ist das Schlüsselintermediat bei der intramolekularen Reaktion von Furanen mit Alkinen – so das Ergebnis von experimentellen und Dichtefunktional-Untersuchungen.
Polymethacrylates with a Covalently Linked Cu II ???Cyclen Complex for the In Situ Generation of Nitric Oxide from Nitrosothiols in Blood We thank the NIH (EB-000783 and EB-004527) for the financial support of this research.
April 2006
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80 Reads
(Figure Presented) In the matrix: A new cross-linked hydrogel polymer, poly(2-hydroxyethyl methacrylate) (pHEMA), containing appended Cu II-cyclen sites (cyclen = 1,4,7,10-tetraazacyclododecane) was prepared and shown to generate nitric oxide from endogenous S-nitrosothiol species (RSNO) typically found in circulating whole blood.
Kinetic and Thermodynamic Control by Chemical Bond Rearrangement on a Si(001) Surface
March 2004
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51 Reads
Changing the force: The driving force that determines the product distribution for acetone adsorbed on the Si(001) surface can be changed from kinetic (producing a four-member-ring species; see scheme) to thermodynamic (producing the dissociation species) upon raising the surface temperature. The results show that the binding of organic molecules to the Si(001) surface is in fact reversible.
Interaction of Gold Clusters with Color Centers on MgO(001) Films
April 2006
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36 Reads
Pricking the surface: STM and EPR spectroscopy demonstrate the presence of color centers on thin MgO(001) films and their interaction with Au atoms. These systems are used to calibrate the IR stretching frequencies of CO bound to Au clusters. Clusters on regular MgO(001) terrace sites remain neutral while nucleation at color centers results in a charge transfer from the surface to the Au cluster. (Figure Presented)
When the reporter induces the effect: Unusual IR spectra of CO on Au 1/MgO(001)/Mo(001)
April 2006
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39 Reads
Innocence lost: The IR spectra of Au/CO complexes adsorbed on of a MgO(001) film differ from the corresponding neutral Au clusters. Calculations indicate this shift of 200-250 cm-1 can be associated with a negative charge on the Au/CO complex. For Au/CO complexes on so-called color centers a charge transfer is expected, however Au atoms on terrace sites are neutral. Thus, CO in fact induces the charge transfer instead of reporting the charge state of the adsorbed Au atoms. (Chemical Equation Presented)
Dissociation of SO 2 on Au/TiC(001): Effects of Au-C Interactions and Charge Polarization
August 2008
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22 Reads
Activating gold: High-resolution photoemission spectroscopy and DFT calculations were used to study the interaction of SO2 with Au/TiC(001) surfaces. Both revealed molecular adsorption of SO2 on TiC(001) but complete dissociation of the S-O bonds on Au/TiC(001) (see picture). Au/TiC(001) cleaves S-O bonds more efficiently than Au/TiO 2(110) or Au/ MgO(100) and decomposes SO2 at temperatures as low as 150 K. (Graph Presented).
Palladium Monomers, Dimers, and Trimers on the MgO(001) Surface Viewed Individually
November 2007
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23 Reads
Atom by atom: The formation of palladium dimers and trimers from single palladium atoms adsorbed on the surface of a thin MgO(100) film has been observed with a low‐temperature scanning tunneling microscope. Combining experimental results and DFT calculations allows the adsorption sites, the geometry, and the electronic properties of the palladium particles to be determined. These are found to have the structures predicted to be most stable on the MgO surface.
