High-nuclearity cluster

Carbon yields, 72 274 Carbonylation, 73 654-656 ionic liquids in, 26 882-885 methanol, 76 315 of methyl acetylene, 7 6 245 reaction, 70 506-507 Carbonyl bromide, 4 300 Carbonyl clusters, high nuclearity, 76 64-66... [Pg.144]

Heteronuclear Carbonyls and High Nuclearity Carbonyl Clusters... [Pg.64]

Syntheses, crystallization, structural identification, and chemical characterization of high nuclearity clusters can be exceedingly difficult. Usually, several different clusters are formed in any given synthetic procedure, and each compound must be extracted and identified. The problem may be compounded by the instabiUty of a particular molecule. In 1962 the stmcture of the first high nuclearity carbide complex formulated as Fe (CO) C [11087-47-1] was characterized (40,41) see stmcture (12). This complex was originally prepared in an extremely low yield of 0.5%. This molecule was the first carbide complex isolated and became the foremnner of a whole family of carbide complexes of square pyramidal stmcture and a total of 74-valence electrons (see also Carbides, survey). [Pg.65]

The main synthetic route to high nuclearity metal carbonyl clusters involves a condensation process (/) a reaction induced by coordinatively unsaturated species or (2) a reaction between coordinatively saturated species in different oxidation states. As an example of (/), Os2(CO)22 can be condensed to form a series of higher coordinated species (89). [Pg.68]

Figure 25.11 Metal frameworks of some high-nuclearity binary carbonyl and carbonylate clusters of osmium (a) Os5(CO)i6 (trigonal bipyramid) (b) Os6(CO)ig (bicapped tetrahedron, or capped trigonal bipyramid) (c) [Os6(CO)ig] (octahedron) (d) Os7(CO)2i (capped octahedron) (e) [Osg(CO)22] (bicapped octahedron) (f) [Osi7(CO)36] (3 shaded atoms cap an Osu trigonal bipyramid).

High nuclearity clusters [Au(AuPR3) ]JC+ with central gold atoms adopt two types of structure those with 12n + 18 electrons have essentially spherical structures, whereas those with 12n + 16 electrons have the peripheral atoms on the surface of a toroid. [Pg.320]

Whereas many high-nuclearity metal clusters have CO as a ligand, all known high-nuclearity Au clusters are coordinated with tertiary phosphines. [Pg.477]

Reactions of clusters with mononuclear or dinuclear metal complexes frequently provide a method of expanding the metal core nuclearity under controlled conditions. The majority of medium- and high-nuclearity homometallic clusters has been prepared from lower-nuclearity cluster precursors by thermolyses ("heat-it-and-hope ) reactions. This is less true of the heterometallic clusters in this... [Pg.90]

The electronic, optical, and magnetic properties of metal clusters are of great current interest, but these properties have been little studied with very mixed -metal clusters. This is to some extent a reflection of the difficulty of preparing high-nuclearity examples many of these interesting properties become important upon increasing cluster size. The limited magnetic studies to date are... [Pg.130]

Park S, Wasileski SA, Weaver MJ. 2001. Electrochemical infrared characterization of carbon-supported platinum nanoparticles A benchmark structural comparison with single-crystal electrodes and high-nuclearity carbonyl clusters. J Phys Chem B 105 9719 -9725. [Pg.561]

The reaction with [Mn(CO)5]2 or [Co(CO)4]2 also led to mixed-metal clusters.962,963 Osmium-palladium mixed-metal carbonyl clusters were made using the unsaturated cluster [Os3(CO)io(/r-H)2] and the carbido cluster [Os5(/U5-C)(CO)15].964 970 Treatment of [Os3(CO)10Gu-H)2] with [Pd2(/u-dppm)2Cl2] afforded the novel high-nuclearity osmium-palladium mixed-metal carbonyl clusters [Os5Pd6(CO)13( -CO)5(/u-H)2(/u-dppm)2], [Os5Pd6(CO)13(//-CO)6(/u-dppm)2], and... [Pg.654]

Lewis, J. Raithby, P. R. High Nuclearity Osmium-Gold Clusters. In Metal Clusters in Chemistry, Vol. 1, Braun-stein, P. Oro, L. A. Raithby, R. R. Eds. Wiley-VCH Weinheim 1999, pp 348-380. [Pg.1142]

More recently, Adams and coworkers have provided a very interesting case of heteronuclear clusters that are very active for the hydrogenation of alkynes [4, 54, 55]. The high-nuclearity layer-segregated Pt-Ru complex [Pt3Ru6(CO)21(jU3-H)(/ -H)j], consisting of three stacked triangular layers of metal atoms with an... [Pg.209]

High molecular weight synthetic alkylated aromatic feedstocks, 23 533 High nuclearity carbonyl clusters, 16 64-66 High nuclearity metal carbonyl synthesis, 16 66-69 from salts, 16 68 from smaller carbonyls, 16 68-69 High ortho novolacs... [Pg.436]

Metal bromides, 4 322-330 Metal can food packaging, 18 37-39 Metal-carbene complexes, 26 926 Metal-carbon compounds, 4 648, 650 Metal-carbon eutectic fixed points, 24 454 Metal carbonyl catalysts, supported, 16 75 Metal carbonyl complexes, 16 73 Metal carbonyls, 15 570 16 58-78 bonding and structure of, 16 59-64 from carbon monoxide, 5 12 in catalysis, 16 72-75 economic aspects of, 16 71 health and safety aspects of, 16 71 heteronuclear, 16 69-71 high nuclearity, 16 66-69 high nuclearity carbonyl clusters, 16 64-66... [Pg.565]

The incorporation of bridging germanium ligands into high-nuclearity transition metal clusters has been accom-plished. Thermal reaction of Ph3GeH with rhodium carbonyl yields a mixture of germanium/rhodium cluster... [Pg.759]

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