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Clustering structural data

On the basis of the available structural data, evidence has accumulated for a common ancestral 8Fd with two [Fe4S4l clusters for both monocluster (3Fe and 4Fe) and dicluster (7Fe and 8Fe) Fds. The evolutionary aspects of Fds have been discussed in detail in several reviews (52, 60) and the arguments will not be repeated here. It is worth noting, however, that the higher potential [Fe3S4] ° clusters are believed to have evolved from their low potential [Fe4S4] counterparts in order to facilitate higher potential electron transport processes. [Pg.6]

The literature/X-ray data was sparse (-1000), so the information content was amplified by generating vast numbers of alternative conformations (-10 ) with a 64-node Linux cluster. Typically, we were able to generate 1 distinct conformation per compound in an average of <1 per minute. At critical points during the drug discovery process, such as when new structural data was obtained, we retrained our free energy model to improve its performance. [Pg.341]

Two reviews18,19 with 20 references are presented. A series of Pd clusters containing from four to several hundred Pd atoms in the metal skeleton was prepared and characterized with structural data and by chemical properties including catalytic activity. [Pg.557]

Our work was initiated on the reduced ternary molybdenum oxides with the thought that the metal cluster electron count (MCE) should be variable for the Mo308 cluster units. Based on Cotton s previous molecular orbital treatment of such clusters (16) it appeared that MCE s from 6 to 8 could be accommodated, but it was not clear whether the seventh and eighth electrons would occupy bonding or antibonding orbitals with respect to the M-M interactions. We thus set about to determine this from structural data on suitable compounds. The attempted replacement of Zn2+ with Sc3+ to secure the compound ZntSc°Mo308 was conducted via the reaction shown in equation 1. [Pg.265]

For updating the information presented in this chapter, a literature search on the keyword nitrogenase modified with structure, X ray, Mossbauer, iron sulfur cluster, or model compound will generate citations referring to the newest research results. A search of the Protein Data Bank (PDB) at the website address http //www.rcsb.org/pdb/ will yield the latest updates on X ray, NMR, and other submitted structural data. [Pg.262]

The available structural data on the tetranuclear carbonyl clusters are summarized in Table 6. [Pg.20]

Reduction of bulky organohalogermylenes leads to the formation of pentametallic germanium clusters 149 and 150 (Equations (260) and (261), respectively).322 The structure of 149 is shown in Figure 8, and selected structural data are collected in Table 32. The five germanium atoms are held together by six two-center, two-electron bonds, and a lone pair resides on the unsubstituted Ge(5) atom. [Pg.777]

Extended X-ray absorption fine structure (EXAFS) studies on the Fe/Mo/S aggregate in nitrogenase have made available structural data that are essential in the design of synthetic analog clusters. Analyses of the Mo K-edge EXAFS of both the Fe-Mo protein and the FeMoco (9) have shown as major features 3-4 sulfur atoms in the first coordination sphere at 2.35 A and 2-3 iron atoms further out from the Mo atom at 2.7 A. The Fe EXAFS of the FeMoco (10,11) shows the average iron environment to consist of 3.4 1.6 S(C1) atoms at 2.25(2) A, 2.3 +0.9 Fe atoms at 2.66(3) A, 0.4 0.1 Mo atoms at 2.76(3) A and 1.2 1.0 0(N) atoms at 1.81(7) A. In the most recent Fe EXAFS study of the FeMoco (11) a second shell of Fe atoms was observed at a distance of 3.75 A. [Pg.391]

High-nuclearity carbonyl clusters, 30 123-222, see also specific metal and clusters decrease in cluster nuclearity, 30 152 interstitialhydrido, NMR data, 30 168 large hydrido clusters, structure, 30 168-172... [Pg.134]

X-ray crystallography, 40 20-21 synthetic models, 40 23-48 xanthane oxidase, 40 21-23 chalcogenide halides, 23 370-377, 413 Chevrel phases, 23 376-377 metal-metal bonding, 23 330, 373 structural data, 23 373-376 as superconductors, 23 376 synthesis, 23 371-372 chloride, 46 4-24, 35-44 heterocations of, 9 290, 291 cluster compounds, 44 45-46 octahedral, 44 47-49, 53-63 electronic structure, 44 55-63 molecular structure, 44 53-54 synthesis, 44 47-49 rhomboidal, 44 75-82 solid-state clusters and, 44 66-72, 74-75, 80-82, 85-87 tetrahedral, 44 72-75 triangular, 44 82-87 cofactor, 40 2, 4-12 anaerobic isolation, 40 5 molybdopterin and, 40 4-8 reduced form, 40 12 synthesis, 40 8-12 xanthine oxidase, 45 60-63 complexes... [Pg.188]


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See also in sourсe #XX -- [ Pg.99 ]




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