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Showing 1 to 20 of 42 for “"Metal Clusters"”.
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Metal clusters: Morphology and chemical properties
Restriction data tranferred 2014-07-01T11:17:03-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission
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The Chemistry of Triruthenium Hydrocarbyls (Metal Clusters)
The triruthenium methylidyne cluster, HRu(,3)(CO)(,10)((mu)(,3)-CH), was prepared by a hydride addition/protonation sequence from HRu(,3)(CO)(,10)((mu)-COCH(,3)). Variable temperature ('1)H and ('13)C NMR experiments suggest the intermediacy of a formyl complex, presumably …
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Vibrational and anion photoelectron spectroscopy of transition metal clusters
… physics. The bonding mechanisms of transition metal atoms still constitute a challenge in their theoretical de scription due to the massive number of valence electrons. Moreover, small transition metal clusters and their complexes may serve as models for catalytic systems of interest for …
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Synthesis and characterization of trinuclear metal clusters containing benzynechromium tricarbonylh
… this thesis is directed towards the synthesis of metal cluster derivatives of benzynechromium tricarbonyls. To this end a number of phosphino- and arsinobenzenechromium tricarbonyl ligands such as ER2C6H5Cr(C0)3 (ER2 = PEt2,AsMe2, PPri2, PBut2) and ER[C6H5Cr(C0)3]2 (ER = AsPh, PEt, PBut) have …
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Templating Metal Clusters via Resorcinarene- and Cyclen- Based Ligand Platforms
Polynuclear metal sites, found in both metalloenzymes and heterogeneous catalysts, play a critical role in small molecule activation by enabling multi-electron redox transformations through cooperative reactivity. One of the most compelling examples is biological nitrogen fixation, mediated by the …
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Synthesis of Mixed Transition Metal Clusters of Osmium and Rhenium via Metal Hydride Coupling Reactions
The metal hydride coupling reaction, which has been used here to produce mixed metal clusters, is dependent upon the HRe(CO)(,5) unit initially serving as a two-electron donor to the lightly stabilized clusters Os(,3)(CO)(,12-x)S(,x) (S = CH(,3)CN, C(,8)H(,14); x = 1 or 2). From this point, all …
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Preparing Main Group Metal Clusters from Organoaluminium Reagents; New Possibilities in Alkali-Activated Polymer Crosslinking
… to the formation of different Al-based molecular clusters, depending on the nature of R, the reaction stoichiometry and the character of the benzoic acid derivative. The obtained compounds were characterised in the solid state by X-ray diffraction methods and two main motifs were observed. When …
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Model Chemistry on Metal Surfaces: Synthesis, Structure and Reactivity Studies of Tungsten-Osmium Mixed-Metal Clusters
… with CpW(CO)(,2)(CTol) provides four mixed-metal compounds, i.e. CpWOs(,3)(CO)(,11) (mu)(,3)-(eta)('2)-C(O)CH(,2)Tol (1), CpWOs(,3)(CO)(,10)((mu)(,3)-CTol)(,2)H (2), Cp(,2)W(,2)Os(CO)-(,7)((mu)(,3)-(eta)('2)-C(,2)Tol(,2)) (3),
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OCTAHEDRAL METAL CLUSTERS AS MOLECULAR BUILDING BLOCKS OF COORDINATION POLYMERS: SYNTHESIS, CHARACTERIZATION, AND STUDY OF THEIR HOST-GUEST INTERACTIONS
This dissertation work focuses on the use of cyanide-functionalized paramagnetic cluster [(Ta6Cl12i)(CN)12a]3- with valence electron per cluster (VEC) = 15 as molecular building blocks of coordination polymers. Apical cyanide ligands are used as bridging ligands between the cluster and other …
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Synthesis, Structure, and Reactivity of High-Nuclearity Carbido Clusters of Rhenium
… reacts with late transition metal-based electrophiles to yield the mixed-metal clusters (Re$\sb7$C(CO)$\sb{21}$ML$\sb{\rm n}\rbrack\sp{2-}$ and with H$\sp+$ to yield the hydrido species (HRe$\sb7$C(CO)$\sb{21}\rbrack\sp{2-}$. These complexes have been fully characterized by …
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Hafnium Metal-Organic Frameworks: Formation Routes and Defect Engineering
Hafnium Metal-Organic Frameworks: Formation Routes and Defect Engineering Francesca Catherine Noriko Firth Abstract Metal-organic frameworks (MOFs) consist of metal nodes or clusters linked by multidentate organic ligands. By altering the identity of these components, the properties of the MOF can …
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Catalytic and magnetic properties of nanostructured materials generated by ultrasound
… These sonochemically prepared supported iron clusters are amorphous and have particle sizes of 3-10 nm. The sonochemically prepared $\rm Fe/SiO\sb2$ samples have different surface morphologies compared to the conventional $\rm Fe/SiO\sb2$ samples. For the sonochemically prepared $\rm …
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CATHODIC DEPOSITION OF TRIANGULAR TUNGSTEN CLUSTERS FROM IONIC LIQUIDS: AN EXPLORATIVE STUDY
In the present work, the triangular tungsten clusters {[W3O2(O2CCH3)6](H2O)3}(CF3SO3)2 and {[W3O2(O2CCH2CH3)6](H2O)3}(BF4)2. 5.5H2O were dissolved in both hydrophobic and hydrophilic ionic liquids (ILs) and subjected to a cathodic potential of roughly 2V. It was proposed that successful deposition …
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INDUCING ACTIVE SITES IN CLUSTERS: REACTIVITY OF Al13Ix- and Al14Iy- (x=0-2, y=2-4) WITH METHANOL
… may induce active sites on the surface of the metal clusters. To study this, a theoretical investigation was undertaken on Al13Ix- and Al14Iy- (x=0-2, y=2-4) and their reactivity with methanol. The hypothesis was that iodine can induce a Lewis base site on the opposite side of the cluster, …
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Developing Photo-responsive Metal-Organic Frameworks towards Controlled Drug Delivery
… drug release via the use of a light "trigger". Metal-Organic Frameworks (MOFs) are a relatively new class of often highly porous materials that act as "sponges" for the absorption of various small molecules. MOFs are so named because they consist of metal clusters that are linked by organic …
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Reconstruction of Rhodium Clusters During CO Oxidation and Consequences on The Reaction Mechanism
… industry and laboratory consist of supported metal nanoparticles, clusters and isolated (single) atoms. Understanding structure sensitivity and identifying the active site or sites are crucially essential for designing efficient catalysts. To determine the active sites of a catalyst for a …
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Thermodynamic Studies of Metal Carboxylates
… the chemistry and physical properties of metal clusters a quantitative study of the chemical reactivity of numerous metal carboxylates was performed. Dimeric metal carboxylates were chosen for such a study because of the extensive structural information available on them. The …
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Synthetic and Post-Synthetic Methods towards Fine Tuning the Chemical and Physical Properties of Metal-Organic Frameworks
… the chemical and physical properties of metal-organic frameworks (MOFs), with a particular emphasis on modulating redox activity, framework composition, and ionic conductivity. The first part of the work focuses on leveraging MOF-embedded polynuclear metal clusters for multi-electron …
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A CALORIMETRIC STUDY OF LIGHT HYDROCARBON ADSORPTION ON METAL-ORGANIC FRAMEWORKS
The effect of metal-organic framework (MOF) structural modifications on C2 hydrocarbon gas adsorption was studied. Two main MOF structures were modified and tested: UiO-66, which has two types of pores in the structure and can support various functional groups on the organic linker, and MOF-74, …
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