- Systematic Synthesis of Tetranuclear Osmium Clusters by the Reaction of Trinuclear Clusters with ; Crystal Structure of
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The complex reacts with the clusters 12-n(MeCN)n> (n=1 or 2) to afford tetranuclear species (1) and (2), respectively.The pyrolysis of (2) leads to the formation of via the intermediate .The acetonitrile ligand of complex (2) is readily displaced by P(OMe)3 to give > (3) along with small quantities of 2> and 3>.With PPh3 the reaction is so slow that fragmentation occurs and the only product isolated is .The hydride-coupling reaction also occurs between and (X=Cl, Br or I) and the complexes obtained have been fully characterised.These complexes decompose in solution via loss of HX to afford .The reaction between and proceeds smoothly for R=Me (7) or Ph (8) but for R=H the major product isolated is .All the products were characterised by i.r., 1H and 13C n.m.r. spectroscopy and structural assignments made.The structure of the cluster (5) was confirmed by an X-ray analysis and shown to consist of an Os3 triangle with a pendant OsH(CO)4 unit co-ordinated to it.One edge of the triangle is bridged by both a hydride and a bromide ligand while another edge is bridged by a hydride.
- Ditzel, Evert J.,Johnson, Brian F. G.,Lewis, Jack,Raithby, Paul R.,Taylor, Michael J.
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p. 555 - 564
(2007/10/02)
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- Mononuclear hydrido alkyl carbonyl complexes of osmium and their polynuclear derivatives
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Osmium hydrido alkyl carbonyl complexes cis-Os(CO)4(H)R (R = Me, Et) can be prepared by alkylation of [Os(CO)4H]- with the corresponding alkyl fluorosulfates. The thermal decomposition of these complexes gives dinuclear and trinuclear derivatives HOs2(CO)8R and ROs3(CO)12R. Other dinuclear complexes can be obtained from similar reactions of hydrides with alkyl carbonyl complexes. The course of the reaction of cis-Os(CO)4(H)CH3 with Ph3P depends upon the reaction conditions: with complete exclusion of air (Ph3P)Os(CO)4 and CH4 are obtained, whereas small amounts of air induce the rapid operation of a radical-chain substitution mechanism and the formation of Os(CO)3(PPh3)(H)CH3.
- Carter, Willie J.,Kelland, John W.,Okrasinski, Stanley J.,Warner, Keith E.,Norton, Jack R.
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p. 3955 - 3960
(2008/10/08)
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- A High-pressure Infrared Study of the Stability of Some Ruthenium and Osmium Clusters to CO and H2 under Pressure
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A high-pressure i.r. study has been made of the stability of some high-nuclearity carbonyl clusters of ruthenium and osmium to carbon monoxide and hydrogen, and of the thermal stabilities of theses clusters under an inert atmosphere.In solution, the hexanuclear cluster reacts with CO (90 atm, 160 deg C, 1 h) to produce the new pentanuclear cluster and .In contrast, in the solid state adds 2 mol of CO to form .The pentanuclear carbonyl undergoes reaction with CO to give both and , and with to give .On heating in an inert atmosphere loses CO to generate .This reaction is reversible.Reaction of , , , or with H2 under moderate pressure and temperatures gives and OsH2(CO)4>; first produces and proceeds to the same pruducts.On carbonylation under pressure yields , and gives a mixture of and .Pyrolysis of under argon at 120 deg C gives the hexanuclear carbide in high yield.
- Nicholls, J. Nicola,Farrar, David H.,Jackson, Peter F.,Johnson, Brian F. G.,Lewis, Jack
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p. 1395 - 1400
(2007/10/02)
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