I.r. and E.X.A.F.S. characterisation of a supported osmium cluster carbonyl

Besson, Bernard; Moraweck, B.; Smith, Anthony K.; Basset, J. M.; Psaro, Rinaldo; Fusi, A.; Ugo, R.

doi:10.1039/c39800000569

Cited by 44 publications

(14 citation statements)

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“…We have examined the cases where E = O ([Os 3 (CO) 10 (μ-H){μ-S(CH 2 ) 3 OH}], 6); S (8,9,10) or COO (11). In all cases, the negative mode ToF-SIMS spectra of the grafted osmium clusters showed major fragments attributable to [Os 3 (CO) n (μ-H)(μ-S)] − (n 9); that for 10 on ZnO is shown in Fig.…”

Section: Deposition On Zno and In 2 Omentioning

confidence: 99%

The deposition of osmium carbonyl clusters onto inorganic oxide surfaces: A ToF-SIMS and IR spectroscopic study of the surface species

Li¹,

Leong²

2008

Journal of Colloid and Interface Science

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Section: Deposition On Zno and In 2 Omentioning

confidence: 99%

The deposition of osmium carbonyl clusters onto inorganic oxide surfaces: A ToF-SIMS and IR spectroscopic study of the surface species

Li¹,

Leong²

2008

Journal of Colloid and Interface Science

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“…3) [49,50]; spectroscopic data obtained on this metal centre agree closely with those obtained for model complexes [45,49,50], one of which, [HOs(CO)10(OSiEt3)], represents a particularly close relationship to the grafted cluster and has been characterised by X-ray diffraction [51]. The grafted sample "HOs3(CO)1O(0-[Al])" [49,50,52] has been the subject of much study. The chemistry on alumina is similar.…”

Section: Z Metal Carbonyl Cluster Complexesmentioning

confidence: 52%

“…3) [49,50]; spectroscopic data obtained on this metal centre agree closely with those obtained for model complexes [45,49,50], one of which, [HOs(CO)10(OSiEt3)], represents a particularly close relationship to the grafted cluster and has been characterised by X-ray diffraction [51]. 3) [49,50]; spectroscopic data obtained on this metal centre agree closely with those obtained for model complexes [45,49,50], one of which, [HOs(CO)10(OSiEt3)], represents a particularly close relationship to the grafted cluster and has been characterised by X-ray diffraction [51].…”

Section: Z Metal Carbonyl Cluster Complexesmentioning

confidence: 99%

“…Direct observation of the hydride by infrared spectroscopy was not possible due to absorptions of the support itself [45]. Oxidation of the cluster by the support occurs more readily on alumina than silica and also affords OsII(CO)n [n = 2 and 3] centres [49,50,52]. So an alternative structure for this species has been proposed ( Fig.…”

Section: Z Metal Carbonyl Cluster Complexesmentioning

confidence: 99%

“…There have been widely differing proposals concerning the nature of these metal sites, but the balance clearly indicates a coordination site containing only oxygen and the CO ligands with no direct osmiumosmium bonding [49,50,[55][56][57]; these units are detectable by electron diffraction [53,58] and may well form some sort of aggregate. Weak EPR signals are also displayed (due to 1-2 7. of the metal content) which may be due to small proportions of Osl and Oslll fragments [59].…”

Section: Z Metal Carbonyl Cluster Complexesmentioning

confidence: 99%

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Reaction of Organometallics with Surfaces of Metal Oxides

Evans

1988

Surface Organometallic Chemistry: Molecular Approaches to Surface Catalysis

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Organometallic complexes can be introduced onto metal oxide supports either by direct bonding or via an intervening ligand. The former method uses the diverse reaction sites available on oxide surfaces. The chemisorption processes may be considered in the same way as reactions of organometallic complexes in solution. For example, interaction of Rh(allyl)3 with silica causes an electrophilic cleavage of one metal-allyl bond to generate a new metal centre, viz.[Si]-ORh(allyl)2' Alternatively, interaction of RU3(CO)12 with silica proceeds via an oxidative addition reaction of a silanol group across one of the metal-metal bonds. Nuclearity is not always maintained during anchoring procedures, as in the case of the interaction of Rh4(CO)12 with alumina, in which mononuclear metal centres are produced. Some of the coordination centres derived from these grafted organometallic complexes have close analogues in mainstream organometallic chemistry; others appear to have no discrete counterpart at present and offer a challenge to the synthetic chemist. Organometallics also provide alternative routes to supported metal particles. In some instances these may be formed under much milder conditions than conventional reductions of metal salts. By virtue of the differing kinetics involved, different (often smaller) particle sizes, compositions, and size distributions become available. Ligandtethered complexes may be synthesised with high specificity. However, subsequent surface reactions occur to give new coordination centres. If the aim is to anchor a known homogeneous catalyst, then precautions must be taken to avoid these, either by protective silylation or by design of a stabilising tethering ligand. But the original tethered complex may be used as a catalyst precursor, and so these surface reactions may be of interest. Many new catalysts have been prepared by supporting organometallic complexes on oxide supports. Establishing the metal coordination site requires a combination of total product analysis and direct spectroscopic measurements characterizing the supported complex, preferably aided by reference to close model compounds. This is now considerably easier with the range of techniques presently available. For a high proportion of materials, the oxide surface binding site is not understood. Progress in this is necessary 47

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On the Origins and Development of “Surface Organometallic Chemistry”

Basset

Ugo

2009

Modern Surface Organometallic Chemistry

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I.r. and E.X.A.F.S. characterisation of a supported osmium cluster carbonyl

Cited by 44 publications

References 0 publications

The deposition of osmium carbonyl clusters onto inorganic oxide surfaces: A ToF-SIMS and IR spectroscopic study of the surface species

The deposition of osmium carbonyl clusters onto inorganic oxide surfaces: A ToF-SIMS and IR spectroscopic study of the surface species

Reaction of Organometallics with Surfaces of Metal Oxides

On the Origins and Development of “Surface Organometallic Chemistry”

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