Solvent induced disproportionation of alkyl(amido)magnesium species containing a (2-pyridyl)amido unit: Synthetic, theoretical and NMR spectroscopic studies of bis(amido)magnesium compounds

K.W. Henderson, Robert Mulvey, A.E. Dorigo

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Reaction of R(2-pyr)NH (where R = Me, Ph or 2-pyr) with 'Bu(2)Mg' in an ether-free environment yields the corresponding alkyl(amido)magnesium derivative [{R(2-pyr)NMgBu}(n)]. When polar solvent is added to these species only bis(amido)magnesium compounds separate from solution and not the expected solvated alkyl(amido) derivatives. Isolation of one such alkyl(amido) compound prior to reaction with donor solvent proves that the mixed anion species do indeed exist, However, when polar molecules are introduced a disproportionation reaction ensues, yielding the homoleptic compounds [{R(2)Mg .(S)(x)}(n)] and [{(R(2)N)(2)Mg .(S)(x)}(n)], where S is THF, TMEDA or PMDETA. Theoretical calculations likewise show that the disproportionation reaction of model compounds closely related to our systems is strongly exothermic. A H-1/C-13 NMR spectroscopic study was used to assign the nature of the bis(amido) species in solution. From these analyses it was possible to propose that the solvated bis(amido) derivatives assume a common structural motif, that of a monomer (n = 1) with a pseudo-octahedral magnesium center.

Original languageEnglish
Pages (from-to)139-146
Number of pages8
JournalJournal of Organometallic Chemistry
Volume518
Issue number1-2
DOIs
Publication statusPublished - 12 Jul 1996

Keywords

  • magnesium
  • amido
  • ab initio MO calculations
  • disproportionation
  • ray crystal structures
  • aryl compounds
  • metal alkyl
  • colligative measurements
  • solid state
  • lithium
  • tetrahydrofuran
  • amides
  • complexes
  • reagent

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