Structurally defined zincated and aluminated complexes of ferrocene made by alkali-metal-synergistic syntheses

William Clegg, Elaine Crosbie, Sophie H. Dale-Black, Eva Hevia, Gordon W. Honeyman, Alan R. Kennedy, Robert E. Mulvey, Donna L. Ramsay, Stuart D. Robertson

Research output: Contribution to journalArticle

25 Citations (Scopus)
79 Downloads (Pure)

Abstract

Reaction of ferrocene with 1 or 2 molar equiv of the synergistic-operative bimetallic sodium zincate base TMEDA·Na(μ-TMP)(μ-tBu)Zn(tBu) yields mainly mono- or dizincated complexes TMEDA·Na(μ-TMP)[μ-(C5H4)Fe(C5H5)]ZntBu (1) and [TMEDA·Na(μ-TMP)Zn(tBu)]2(C5H4)2Fe (2). Likewise, the separated pairing of Li(TMP) and (TMP)AliBu2 in the presence of THF can mono- or dimetalate ferrocene in a synergistic two-step lithiation/trans-metal-trapping protocol to give THF·Li(μ-TMP)[μ-(C5H4)Fe(C5H5)]Al(iBu)2 (4) or [THF·Li(μ-TMP)Al(iBu)2]2(C5H4)2Fe (5). In the absence of Lewis donating cosolvents, a 4-fold excess of the sodium zincate appears to produce an unprecedented 4-fold zincated ferrocene of formula Na4(TMP)4Zn4(tBu)4[(C5H3)2Fe] (3), whereas when donor solvent is withheld from the lithium/aluminum pairing, only dimetalation of ferrocene is possible. Tetrametalation seems to be inhibited by the in situ generation of TMP(H) via amido basicity, which then acts as a Lewis donor toward lithium, preventing inverse-crown formation and preferentially forming the Lewis acid–Lewis base adduct [TMP(H)·Li(μ-TMP)Al(iBu)2]2(C5H4)2Fe (6). With the exception of 3, all aforementioned complexes have been characterized by X-ray crystallography, while 1–6 have also been studied by solution NMR spectroscopic studies.
Original languageEnglish
Pages (from-to)2580-2589
Number of pages10
JournalOrganometallics
Volume34
Issue number11
Early online date4 Feb 2015
DOIs
Publication statusPublished - 2015

    Fingerprint

Keywords

  • ferrocene
  • solvents
  • zinc pairing
  • aluminium pairing
  • Tetrametalation

Cite this