Clusters homometallic

Two subsections are added. One is 6.2.5 on reactions involving chalcogeno Mo and W clusters, which is subdivided further into polyoxohomopolymetalates polyoxoheteropolymetalates chalcogeno (S, Se) cuboidal clusters, general [S, Se clusters], homometallic and [S, Se clusters], heterometallic. The second added subsection is 8.1.5 on reactions involving the Prussian blues . 

Chalcogeno (S, Se) cuboidal clusters, homometallic. Reductants including Mg, V, [MoCU] ", Mo2Cl8]" and HPH2O2 in variorrs conditions convert Mo3S4" ... 

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... 

Ligand fluxionality on metal clusters has been the subject of many studies, the majority of reports focusing on carbonyl migration on homometallic tri- and... 

Relatively few investigations involving palladium carbonyl clusters have been carried out, partly because palladium per se does not form stable, discrete homometallic carbonyl clusters at room temperature in either solid or solution states.114,917-922 Nevertheless, solution-phase palladium carbonyl complexes have been synthesized with other stabilizing ligands (e.g., phosphines),105,923 and carbon monoxide readily absorbs on palladium surfaces.924 Moreover, gas-phase [Pd3(CO)n]-anions (n = 1-6) have been generated and their binding energies determined via the collision-induced dissociation method.925... 

In addition to these homometallic (rhodium) clusters, several hetero-metallic clusters of the type [M M CO o]2, where M and M1 are each different metals selected from the Co, Rh, Ir triad (jc = 1-11), have been described and claimed to be useful catalysts in the reaction between carbon monoxide and hydrogen to produce oxygenated products (68, 69). These complexes can be prepared from the heterometallic dodecacar-bonyl complexes, [MuM (CO)12] (M, M1 = Co, Rh, or Ir y = 1-3), by simply mixing the appropriate dodecacarbonyl species in THF under nitrogen and then adding water (70). They can be isolated by adding a suitable cation e.g., Al3+, Mg2+, Ca2+, etc. 

In a more general context, metal carbonyls on zeolites can be a unique way to prepare highly dispersed metal catalysts. In the present work, this is especially the case for iron as no other mild methods are operative. It is expected that the method could be applied to the preparation of bi- and polymetallic catalysts even though the starting material are not bi- or polymetallic clusters, but more conveniently homometallic clusters. 

Among the less common oxidation states those of I and III have the most significance. Complexes of platinum(III) have been of interest for many years because of their intermediacy in substitution reactions of platinum(II) and (IV). More recently binuclear platinum(I) and (III) complexes have been isolated, and the chemistry of these new complexes will be of increasing interest in platinum chemistry. Platinum forms strong homometallic bonds giving rise to multimetallic chain compounds and cluster complexes. The increasing use of X-ray crystallography, and 31P and 19 PtNMR will allow systematic studies to be made on these multimetallic platinum complexes. 

Binding energy, pentacarbonyliron, 6, 3 Binuclear complexes bis-Cp titanium halides, 4, 522 with Ni-M and Ni-C cr-bonds heterometallic clusters, 8, 115 homometallic clusters, 8, 111 Binuclear dicarbonyl(cyclopentadienyl)hydridoiron complexes, with rand C5 ligands, 6, 178 Binuclear iridium hydrides, characteristics, 7, 410 Binuclear monoindenyl complexes, with Ti(IV), 4, 397 Binuclear nickel(I) carbonyl complexes, characteristics, 8, 13 Binuclear osmium compounds, with hydrocarbon bridges without M-M bonds, 6, 619... 

Nickel-metal bonds, binuclear and polynuclear complexes, homometallic clusters, 8, 111 Nickel nanoparticles, preparation, 12, 87 Nickel-nitriles, synthesis and reactivity, 8, 150 Nickelocenes... 

Two homometallic octanuclear clusters, [FegS CNBu1) ] [37] and [Fe8S8 (PCy 3)61 [37,38], have been isolated (see earlier discussion), as has the related heterometallic cluster [Mo2Fe6S8(PEt3)6(tccat)2] [70], The latter cluster is the first example of an Fe—S edge-linked, reduced MoFe3S4 double-cubane with Mo atoms at the periphery of each cuboid subunit. The reduced double-cubane core is stabilized by triethylphosphane coordinated to the Fe atoms. The utility of such materials as precursors to potential cofactor models, both structural and functional, has yet to be explored. 

The analogy with both surface-bound and cluster faces bridging i,3-CO has its counterpart in the q3-CNR ligation. This triply bridging bonding mode was crystallographically evidenced in some homometallic and heterometallic... 

A few homometallic HNCC have also been produced by the condensation reactions of anionic carbonyl clusters with cationic complexes. For instance, sequential buildup of rhodium HNCC via incorporation of Rh(CO)2 fragments has been achieved by reacting [Rh(CO)2(MeCN)2] in acetonitrile with a series of anionic rhodium clusters as illustrated by the reactions shown in Eqs. (11) and (12) (223). 

---