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Clusters structures

Being small and high field, carbon monoxide is the most common ligand in low valent organometalhc metal clusters, for example, Ru3(CO)i2 (13.1). CO is small enough to bind in sufficient numbers to electronically saturate each metal of the cluster without causing a steric clash with neighboring COs. [Pg.354]

Higher valent clusters such as [Re2Clg] (13 2) also exist. As expected for hard, high valent Re(III), the preferred ligand sets include halides and N and O donors, rarely CO. [Pg.354]

Only the simpler clusters are best described in terms of the 18e rule. For example, each 16e Os(CO)4 group in Os3(CO)i2,13.3, attains 18e by forming two M-M bonds, each bond adding le to the count for each metal. Since the metals have the same electronegativity, the M-M bond is considered as contributing nothing to the oxidation state—the complex thus contains 18e, Os(0). [Pg.355]

The EAN electron count for a cluster of nuclearity x and having y metal-metal bonds is given by Eq. 13.1. [Pg.355]

This means that the Os=Os double bond is really a reflection of the presence of the two hydride bridges, each of which can open to generate a vacant site. This makes the dihydride far more reactive than Os3(CO)i2 and therefore a very useful starting material in triosmium cluster chemistry. [Pg.357]


Bacic Z and Miller R E 1996 Molecular clusters structure and dynamics of weakly bound systems J. Phys. Chem. 100 12,945-59... [Pg.1176]

Parks E K, Welller B H, Bechthold P S, Hoffman W F, NIeman G C, Pobo L G and Riley S J 1988 Chemical probes of metal cluster structure reactions of Iron clusters with hydrogen, ammonia and water J. Chem. Rhys. 88 1622... [Pg.2403]

A novel and far-reaching type of isomerism concerns the possibility of valence isomerism between nonclassical (electron-deficient) clusters and classical" organoboron structures. Thus, n-vertexed /do-boranes. have cluster structures... [Pg.187]

Cation Formal oxidation state Cluster structure Point group symmetry... [Pg.591]

The Roles of Cluster Structure in Copper-mediated Reactions... [Pg.339]

C. Cluster Structural Interconversions and Synthesis of Heterometal Clusters... [Pg.376]

BAC-MP4 method, description, 344-346 Band theory, crystal orbital method, 149 Be clusters, structures, 24-25 Bifurcation... [Pg.423]

Similar to the mixed-halide (Cl, I) 6-13 system, where more chlorine-rich reactions produced a new structure type, materials with an unprecedented zirconium cluster structure are obtained in the Na-Zr-(C1/I)-B system (also with. other cations, see below), when larger Cl/I ratios are used than above. Compounds characterized are Na[(Zr6B)(Cl,I)i4] and Ao.5[(Zr6B)(Cl,I)i4] (with A = Ca, Sr, Ba) [25, 26]. Single crystals of the cubic Na[(Zr6B)Clio.94(i)l3.o6] and... [Pg.68]

Table 5 shows HDS product distributions over several catalysts prepared by using the molybdenum-nickel cluster 2. Sulfur content in decane was adjusted to 5.0 wt% in these experiments. MoNi/NaY was found to be more active than MoNi/Al203. It is to be noted that during the high temperature pretreatment the original cluster structure would have been changed. However, the high activity of the MoNi/NaY catalyst for benzothiophene HDS is probably due to the formation of active sites derived from this particular mixed metal cluster. [Pg.113]

Soler, J.M., Beltran, M.R., Michaelian, K., Garzon, I.L.. Ordejon, P., Sanchez-Portal, D. and Artacho, E. (2000) Metallic bonding and cluster structure. Physical Review B - Condensed Matter, 61, 5771-5780. [Pg.238]

Rousseau, R., Dietrich, G., Kruckeberg, S., Lutzenkirchen, K., Marx, D., Schweikhard, L. and Walther, C. (1998) Probing cluster structures with sensor molecules methanol adsorbed onto gold clusters. Chemical Physics Letters, 295, 41-46. [Pg.245]

PdPt [96,111], CuPt [112], PdRh [113], FeRu [114], FePt [114], FeNi [115], CuNi [116], BiNi [117] nanoparticle alloys or cluster-in-cluster structures by simultaneous reduction were reported, as summarized in Table la and b. [Pg.54]

Our first attempt of a successive reduction method was utilized to PVP-protected Au/Pd bimetallic nanoparticles [125]. An alcohol reduction of Pd ions in the presence of Au nanoparticles did not provide the bimetallic nanoparticles but the mixtures of distinct Au and Pd monometallic nanoparticles, while an alcohol reduction of Au ions in the presence of Pd nanoparticles can provide AuPd bimetallic nanoparticles. Unexpectedly, these bimetallic nanoparticles did not have a core/shell structure, which was obtained from a simultaneous reduction of the corresponding two metal ions. This difference in the structure may be derived from the redox potentials of Pd and Au ions. When Au ions are added in the solution of enough small Pd nanoparticles, some Pd atoms on the particles reduce the Au ions to Au atoms. The oxidized Pd ions are then reduced again by an alcohol to deposit on the particles. This process may form with the particles a cluster-in-cluster structure, and does not produce Pd-core/ Au-shell bimetallic nanoparticles. On the other hand, the formation of PVP-protected Pd-core/Ni-shell bimetallic nanoparticles proceeded by a successive alcohol reduction [126]. [Pg.55]

In his pioneering work Baetzold used the Hartree-Fock (HF) method for quantum mechanical calculations for the cluster structure (the details are summarized in Reference 33). The value of the HF procedure is that it yields the best possible single-determinant wave function, which in turn should give correct values for expectation values of single-particle operators such as electric moments and... [Pg.81]

Room temperature deposition of silver on Pd(lOO) produces a rather sharp Ag/Pd interface [62]. The interaction with a palladium surface induces a shift of Ag 3d core levels to lower binding energies (up to 0.7 eV) while the Pd 3d level BE, is virtually unchanged. In the same time silver deposition alters the palladium valence band already at small silver coverage. Annealing of the Ag/Pd system at 520 K induces inter-diffusion of Ag and Pd atoms at all silver coverage. In the case when silver multilayer was deposited on the palladium surface, the layered silver transforms into a clustered structure slightly enriched with Pd atoms. A hybridization of the localized Pd 4d level and the silver sp-band produces virtual bound state at 2eV below the Fermi level. [Pg.84]

Mammalian metallothioneins typically bind seven metal ions in cluster structures, with bridging sulfur groups, as seen in the x-ray structure of the Cd5Zn2MT complex (86). It is therefore difficult to develop a simple formation-constant description for the binding of metal ions to MT (87), considering that protonation-deprotonation equilibria of the free protein itself should also be taken into account. However, the usefulness of Table VIII as a guide to the affinity of metal ions for mercapto donor ligands is seen in that the ability of metal ions to... [Pg.141]

Fig. 10. Illustration of the similarity between the cluster structure of 3 and the closest packing in A1 metal Rotation of the upper ring of I by 30° leads to a structure II, which can then easily be transformed into a section of the closest packing of A1 metal by shifting in the layer of the page by... Fig. 10. Illustration of the similarity between the cluster structure of 3 and the closest packing in A1 metal Rotation of the upper ring of I by 30° leads to a structure II, which can then easily be transformed into a section of the closest packing of A1 metal by shifting in the layer of the page by...

See other pages where Clusters structures is mentioned: [Pg.434]    [Pg.157]    [Pg.491]    [Pg.722]    [Pg.783]    [Pg.1106]    [Pg.331]    [Pg.337]    [Pg.126]    [Pg.622]    [Pg.1241]    [Pg.13]    [Pg.24]    [Pg.170]    [Pg.228]    [Pg.70]    [Pg.16]    [Pg.343]    [Pg.114]    [Pg.43]    [Pg.206]    [Pg.219]    [Pg.66]    [Pg.278]    [Pg.157]    [Pg.66]    [Pg.62]    [Pg.143]    [Pg.129]    [Pg.948]    [Pg.255]   
See also in sourсe #XX -- [ Pg.61 ]




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Aluminum cluster structure

Argon, cluster structure

Backbone structure cluster structures

Band structure cluster complexes

Borane cluster compounds structures

Carbidocarbonyl clusters structures

Carbon clusters amorphous structures

Carbon clusters electronic structure calculations

Carbon clusters geometrical structure

Carbon dioxide clusters structure

Carbonyl clusters structural parameters

Cationic clusters lowest-energy structure

Central structural unit polynuclear clusters

Closed-cluster composition and structure

Cluster Analysis Recognition of Inherent Data Structures

Cluster and cage structure

Cluster compounds state intermetallic structures

Cluster fractal structure

Cluster fractal structure chaotic fractals

Cluster fractal structure conductivity

Cluster fractal structure lattice structural models

Cluster fractal structure percolation threshold values

Cluster model electronic structure

Cluster models structural transitions

Cluster structural features

Cluster structure elements

Cluster structure transformation

Cluster structure, zero temperature

Cluster structures bare metal anions

Cluster structures bare metal cations

Cluster structures multi-element clusters

Cluster structures production

Cluster structures, classification

Clustering of Structures

Clustering of chemical structures

Clustering structural data

Clusters and crystal structures

Clusters central structural units

Clusters crystal structure

Clusters geometrical structure

Clusters metallic, shell structure

Clusters structural descriptors

Coordination complexes cluster structures

Coupled-cluster electronic structure

Crystal structure calculation cluster method

Crystal structure cluster complexes

Crystal structure prediction clustering

Cubane-type clusters structural parameters

Effects of Electron Correlations and Structure on Cluster Magnetism

Electronic Structure of Metal and Mixed Nonstoichiometric Clusters

Electronic Structure of Naked, Ligated and Supported Transition Metal Clusters from First Principles Density Functional Calculations

Electronic structure cluster complexes

Electronic structure of clusters

Electronic structure of supported clusters

Electronic structure of transition metal clusters

Electronic structure silicon clusters

Electronic structures clusters

Flickering cluster model structure

Fluorite structure defect clusters/cluster models

Fullerene cluster structure

Geometric cluster structure

Gold cluster complexes structure

Gold clusters structures

Gradient-based Methods for Determination of Cluster Structures at Zero Temperature

Group 5 metal halide clusters electronic structure

Group 5 metal halide clusters molecular structure

Heteronuclear clusters structures

Hexanuclear clusters electronic structures

Hydride-transition metal clusters, structures

Icosahedral clusters structure

Induction cluster polarization, structure

Iron clusters structure

Iron, alkyne-substituted clusters structures

Iron-molybdenum-sulfur clusters crystal structure

Iron-molybdenum-sulfur clusters structure

Iron-platinum cluster structure

Iron-sulfur clusters structure

Isoelectronic cluster structure

Krypton, cluster structure

Magnesium clusters structure

Metal cluster superconductors structure

Metal clusters closed electronic structure

Metal clusters structure

Metal clusters, transition structure variation

Metal oxide clusters electronic structures

Methane clusters structure

Mo6S8 cluster, structure

Molecular clusters structure

Molecular structures phase cluster formation

Molybdenum cluster compounds electronic structure

Molybdenum cluster compounds molecular structure

Multiplet structures model clusters

Nafion cluster structure

Nanoscale chemical structure clusters

Neon, cluster structure

Niobium halide clusters electronic structure

Nitrogen cluster structure

Nitrosyl clusters structures

Optimized Structures for the and Clusters

Osmium carbonyl cluster anions, structures

Osmium carbonyl clusters structure

P clusters, structure

Palladium small clusters, electronic structure

Percolation theory cluster structure

Phosphides with clusters structures

Photosystem II manganese cluster of, structure

Platinum carbonyl cluster anions, structure

Polynuclear clusters, structure

Protein Structure Similarity Clustering

Protein structure similarity clustering PSSC)

Putative structure cluster

Reactions Leading to Structural Changes in Clusters

Rhenium catalysts cluster structures

Rhodium carbonyl cluster anion, structure

Rules for Cluster Structure-Electron Counting Correlations

Ruthenium-copper clusters structure

Sodium clusters electronic shell structures

Sodium clusters structure optimizations

Sodium clusters structures

Structural Characteristics of Molecular Metal Clusters

Structural Dynamics of the Active Re10 Cluster

Structural and Bonding Patterns Cluster Chemistry

Structural and Reactivity Aspects of Hetero-Pt Clusters

Structural and Temperature Behavior of Metallic Clusters

Structural cluster model

Structural transition mechanisms, potential clusters

Structure Supercritical” cluster

Structure and Bonding in Heteronuclear Gold Cluster Compounds

Structure and Bonding in Transition-Metal Clusters

Structure and Properties of Ligated Clusters

Structure and Properties of Naked Clusters

Structure and Reactivity of Clusters on Surfaces

Structure cluster complexes

Structure of Au clusters

Structure of Smaller Carbon Clusters

Structure of carbonyl clusters

Structure of clusters

Structure of clusters with

Structure with substituted carbonyl clusters

Structures Clustering

Structures Clustering

Structures and Bonding of Coinage Metal NPFM Clusters

Structures of homoatomic nine-atom clusters

Structures tetrahedral clusters

Structures with finite clusters of tetrahedra and octahedra

Sulfur dioxide clusters structure

The Roles of Cluster Structure in Copper-mediated Reactions

The Structure of Hydride Clusters

Topological structure cluster relationships

Topological structure clustering

Transition metal clusters structural data

Transition metal clusters, boron atoms structure

Transition-metal clusters structure

Trigonal pyramidal structures, atomic clusters

Trinuclear iron-sulfur clusters structures

Ultrafast dynamics cluster structures

Vanadium nitrogenase cluster structure

Water cluster structure

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