Influence of cyclopentadienyl ring-tilt on electron-transfer reactions

Redox-induced reactivity of strained [2] and [3] Ruthenocenophanes

Andrew D. Russell, Joe B. Gilroy, Kevin Lam, Mairi F. Haddow, Jeremy N. Harvey, William E. Geiger, Ian Manners

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    In contrast to ruthenocene [Ru(h5-C5H5)2] and di-methylruthenocene [Ru(h 5-C5H4Me)2] (7), chemical oxidation of highly strained, ring-tilted [2]ruthenocenophane [Ru(η5-C5H4)2(CH2)2] (5) and slightly strained [3]ruthenocenophane [Ru(h5-C5H4)2(CH2)3] (6) with cationic oxidants containing the non-coordinating [B(C6F5)4]- anion was found to afford stable and isolable metal-metal bonded dicationic dimer salts [Ru(h5-C5H4)2(CH2)2]2[B(C6F5)4]2 (8) and [Ru(h5-C5H4)2-(CH2)3]2[B(C6F5)4]2 (17), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting Ru-Ru bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the Ru-Ru bond in 8 was achieved through reaction with the radical source [(CH3)2NC(S)S-SC(S)N(CH3)2] (thiram), affording unusual dimer [(CH3)2NCS2Ru(η5-C5H4)(η3-C5H4)C2H4]2[B(C6F5)4]2 (9) through a haptotropic η53 ring-slippage followed by an apparent [2 + 2] cyclodimerization of the cyclopentadienyl ligand. Analogs of possible intermediates in the reaction pathway [C6H5ERu(η5-C5H4)2C2H4] [B(C6F5)4] [E = S (15) or Se (16)] were synthesized through reaction of 8 with C6H5E-EC6H5 (E = S or Se).

    Original languageEnglish
    Pages (from-to)16216-16227
    Number of pages12
    JournalChemistry - A European Journal
    Volume20
    Issue number49
    DOIs
    Publication statusPublished - Jan 12 2014

    Fingerprint

    Redox reactions
    Dimers
    Metals
    Thiram
    Oxidation
    Dimerization
    Electrons
    Oxidants
    Discrete Fourier transforms
    Cyclic voltammetry
    Anions
    Negative ions
    Salts
    Ligands
    ruthenocene

    Keywords

    • Electron-transfer reactions
    • Organometallic chemistry
    • Ruthenium

    ASJC Scopus subject areas

    • Chemistry(all)

    Cite this

    Influence of cyclopentadienyl ring-tilt on electron-transfer reactions : Redox-induced reactivity of strained [2] and [3] Ruthenocenophanes. / Russell, Andrew D.; Gilroy, Joe B.; Lam, Kevin; Haddow, Mairi F.; Harvey, Jeremy N.; Geiger, William E.; Manners, Ian.

    In: Chemistry - A European Journal, Vol. 20, No. 49, 12.01.2014, p. 16216-16227.

    Research output: Contribution to journalArticle

    Russell, Andrew D. ; Gilroy, Joe B. ; Lam, Kevin ; Haddow, Mairi F. ; Harvey, Jeremy N. ; Geiger, William E. ; Manners, Ian. / Influence of cyclopentadienyl ring-tilt on electron-transfer reactions : Redox-induced reactivity of strained [2] and [3] Ruthenocenophanes. In: Chemistry - A European Journal. 2014 ; Vol. 20, No. 49. pp. 16216-16227.
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    abstract = "In contrast to ruthenocene [Ru(h5-C5H5)2] and di-methylruthenocene [Ru(h 5-C5H4Me)2] (7), chemical oxidation of highly strained, ring-tilted [2]ruthenocenophane [Ru(η5-C5H4)2(CH2)2] (5) and slightly strained [3]ruthenocenophane [Ru(h5-C5H4)2(CH2)3] (6) with cationic oxidants containing the non-coordinating [B(C6F5)4]- anion was found to afford stable and isolable metal-metal bonded dicationic dimer salts [Ru(h5-C5H4)2(CH2)2]2[B(C6F5)4]2 (8) and [Ru(h5-C5H4)2-(CH2)3]2[B(C6F5)4]2 (17), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting Ru-Ru bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the Ru-Ru bond in 8 was achieved through reaction with the radical source [(CH3)2NC(S)S-SC(S)N(CH3)2] (thiram), affording unusual dimer [(CH3)2NCS2Ru(η5-C5H4)(η3-C5H4)C2H4]2[B(C6F5)4]2 (9) through a haptotropic η5-η3 ring-slippage followed by an apparent [2 + 2] cyclodimerization of the cyclopentadienyl ligand. Analogs of possible intermediates in the reaction pathway [C6H5ERu(η5-C5H4)2C2H4] [B(C6F5)4] [E = S (15) or Se (16)] were synthesized through reaction of 8 with C6H5E-EC6H5 (E = S or Se).",
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    AU - Russell, Andrew D.

    AU - Gilroy, Joe B.

    AU - Lam, Kevin

    AU - Haddow, Mairi F.

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    AU - Geiger, William E.

    AU - Manners, Ian

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