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Volumn 24, Issue 22, 2005, Pages 5431-5439

Reversible isomerization of a diphosphine ligand about a triosmium cluster: Synthesis, kinetics, and X-ray structures for the bridging and chelating isomers of Os 3(CO) 10[(Z)-Ph 2PCH=CHPPh 2]

Author keywords

[No Author keywords available]

Indexed keywords

ACTIVATION PARAMETERS; LIGANDS; REACTION RATE; TEMPERATURE RANGE;

EID: 27544444876     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om0505413     Document Type: Article
Times cited : (42)

References (93)
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    • note
    • e.
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    • 31P nuclei are in close agreement with the values determined for other phosphine-substituted inorganic/ organometallic compounds. See: (a) Plourde, F.; Gilbert, K.; Gagnon, J.; Harvey, P. D. Organometallics 2003, 22, 2862.
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  • 42
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    • note
    • P-C = 9 Hz) is readily ascribed to the two axial CO groups at the phosphine-substituted osmium center. The remaining chemical shifts are easily assigned by making use of the fact that the pairwise equivalent equatorial carbonyl groups appear to high field of the axial CO groups.
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    • note
    • 2]: Unpublished results.
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    • 2].
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    • note
    • eq values were found to be relatively temperature insensitive and yielded an average value of 6.9, which was employed in extraction of the individual rate constants associated with the isomerization reaction.
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    • note
    • eq.
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    • note
    • 31P NMR data.
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    • For some other examples exhibiting chelate-ring opening, see: (a) Knebel, W. J.; Angelici, R. J. Inorg. Chem. 1974, 13, 627, 632.
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    • note
    • 13C NMR data to distinguish between the two mechanisms depicted in Scheme 2.
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    • note
    • 3 clusters. For related VT NMR studies, see: (a) References 1c,d.
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    • note
    • The simplicity alluded to stems from the application of Occam's razor.
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    • note
    • In the case of an isomerization reaction involving a dppe ligand, we can envision an intermediate state where the hydrogen atoms of the ethane backbone must adopt an eclipsed conformation during the bridge ⇄ chelate transformation. This specific destabilization is avoided in diphosphines possessing an unsaturated carbon backbone.
  • 77
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    • Unpublished results
    • Unpublished results.
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    • In a subsequent paper by the same researchers, it was disclosed that a multistep process involving the dissociative release of one arm of the diphosphine ligand, followed by phosphine migration and ligand reattachment, was energetically competitive with the concerted phosphine migration process reported in ref 51. Since a dissociative mechanism is not supported by our kinetic data, we can exclude it from consideration. See: Demachy, I.; Jean, Y.; Lledos, A. New J. Chem. 2004, 28, 1494.
    • (2004) New J. Chem. , vol.28 , pp. 1494
    • Demachy, I.1    Jean, Y.2    Lledos, A.3


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.