A new approach to lithium-heavier alkali metal interchange reactions: synthesis of a tetralithium pentasodium mixed alkoxide-amide dome-shaped cage compound with an encapsulated hydroxide molecule

A.R. Kennedy, J.G. MacLellan, R.E. Mulvey, A. Robertson

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An investigation of metal-metal interchange reactions between alkali metal amides and alkali metal alkoxides, relevant to the area of superbases, has uncovered a novel adduct containing both components, which has been isolated from solution and crystallographically characterised. Formulated as [Li4Na4(ButO)4{PhN(H)}4(NaOH)(4-Me-py)4], this tetralithium pentasodium mixed alkoxide-amide can be synthesized either by reaction of lithium anilide with sodium t-butoxide or of sodium anilide with lithium t-butoxide, in the presence of the co-ordinating solvent 4-methylpyridine (4-Me-py). The single sodium hydroxide molecule in the formulation occurs adventitiously, but consistently. X-Ray crystallographic studies reveal a 17-vertex dome-shaped structure founded on a (NaN)4 basal ring, above which lies a smaller (LiO)4 ring then an apical Na atom: the OH- ion occupies an internal position within the dome. Discussion focuses on the striking resemblance between this structure and that of the previously reported tetralithium pentapotassium mixed alkoxide-enolate [Li4K4(ButO)4(C6H11O)4(KOH)(THF)5], and it is pointed out that the dominant factor in their common architectural design appears to be the encapsulated hydroxide molecule.
Original languageEnglish
Pages (from-to)4112-4116
Number of pages4
JournalJournal of the Chemical Society, Dalton Transactions
Issue number22
Publication statusPublished - 27 Oct 2000



  • alkali metal amides
  • alkali metal alkoxides
  • crystallographically
  • sodium anilide
  • X-Ray
  • hydroxide molecule

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