C-cluster

In 1990, a third form of soHd carbon was confirmed and designated TuckniinsterfilUetenes. These 60-carbon (and 78-C) clusters are described as having the shape of a geodesic dome or soccer ball and hence are also known as "bucky balls" (5). 

Heteroatom fullerene-type clusters — The possibility of incorporation of hetero atoms into C clusters has excited the attention of both theoreticians and experimentalists since the earliest days of fullerene chemistry, particularly in view of the known stability and ubiquity of organic heterocycles. The structural relationship between Ceo and /3-rhombohedral boron has already been alluded to (p. 142). 

C. Cluster Stmcturrd Interconversions and S3mthesis of Heterometal Clusters Fuscoredoxin (Novel Fe-S Cluster)... 

C. Cluster Structural Interconversions and Synthesis of Heterometal Clusters... 

Fig. 6.12 (a) A perspective of AxNb6Cli202 structure in the a direction, (b) A view of the cluster framework in AxNb6CI,202 emphasizing the difference in intercluster linkages in the a direction and within the be plane, (c) Cluster unit in AxNb5Cli202-... 

The crystal structures of many organolithium compounds have been determined.44 Phenyllithium has been crystallized as an ether solvate. The structure is tetrameric with lithium and carbon atoms at alternating corners of a highly distorted cube. The lithium atoms form a tetrahedron and the carbons are associated with the faces of the tetrahedron. Each carbon is 2.33 A from the three neighboring lithium atoms and an ether molecule is coordinated to each lithium atom. Figures 7.2a and b show, respectively, the Li-C cluster and the complete array of atoms, except for hydrogen 45 Section 6.2 of Part A provides additional information on the structure of organolithium compounds. 

Figure 5. A schematic model for the structure in TEOS-PTMO hybrid systems, (A) PTMO chain, (B) linear species based on partially condensed TEOS, (C) cluster formed by highly condensed TEOS. 1/s corresponds to the correlation length observed in SAXS profiles.

Longoni, G. Iapalucci, M. C. Clusters in ligand shells. Low-valent organometallic clusters. In Clusters and Colloids From Theory to Applications Schmid, G., Ed., VCH New York, 1994 p 91. 

Figure 2 Structures of the actrive sites of metalloenzymes containing metal-sulfur cluster units, (a) Fe only hydrogenase, H-cluster (Hoxfarm) (b) Sulfite reductase (c) NiFe carbon monoxide dehydrogenase, C-cluster and (d) NiFe carbon monoxide dehydrogenase, A-cluster, which functions as acetyl-CoA synthase...

CODHs catalyse the oxidation of carbon monoxide in a reversible, two-electron process. They are homodimeric enzymes with five metal clusters, two C-clusters that catalyse the oxidation of CO to C02 and three typical [Fe4S4] cubane clusters (Figure 15.4). 

Figure 15.5 (Left) The C-cluster of CODH from C. hydrogenoformans and (right) the A-cluster from C. hydrogenoformans. Fe, rust S, yellow Ni, green N, blue C, grey O, red. (From Drennan et al., 2004. With kind permission of Springer Science and Business Media.)...

Each lobe of the sp orbital containing one-electron overlap head-on carbon atoms and translational repetition of this tetragonal C-C cluster makes diamond. The three tetrahedral arms of orbital can also be terminated by hydrogen atoms that overlap head-on. If terminated by hydrogen, the tetrahedral C-H cluster makes the CH molecule of gas methane (Fig. 4.4). 

C active clusters with size R are defined by randomly placing C nonoverlapping circles of radius R into the 2D space of the simulated dataset. Points that happened to be within each of the C circles are defined as active points, which simulate C clusters of active molecules while points outside the circles are defined inactive. Each cluster with active points is referred to as an active cluster. 

A from the three neighboring lithium atoms. An ether molecule is coordinated to each lithium atom. Figure 7.2a shows the Li-C cluster, and Fig. 7.2b shows the complete array of atoms, except for hydrogen.36 Section 7.1 of Part A provides additional information on the structure of organolithium compounds. 

Figure 1.11. Schematic diagrams of (a) and (b) Fei j O point defect clusters (after Koch and Cohen 1969) (c) clustering in fluorite-type structures and (d) the Cap2 structure.

A similar equation may be written to describe the evolution of the singlet density of the reactant C. Cluster functions are introduced and, after using a super-position approximation again, the analysis follows that of Kapral [285] very closely with the complication that, instead of only singlet XA and doublet xAB correlation functions, it is necessary to consider the equation for C in tandem. This requires the use of the matrix notation for compactness. 

Oxidation of CO may require cooperation of the nickel ion and the Fe4S4 group within the C cluster. 

The dihydride H2RusC(CO)147 has been reported, although its characterization was based entirely on an analysis of its infrared spectrum.20 In contrast, H2RuftC(CO)i6 8 has been prepared and fully characterized.15 Compound 8 can be made by acidification of the dianion [Ru6C(CO)16J2 4 with H2S04 in acetonitrile at -30°C. Cluster 8 may also be prepared via stepwise protonation from 4. Treatment of a dichloromethane solution of... 

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