Toward the catalytic synthesis of phosphiranes. A computational study

T. P.M. Goumans, Andreas W. Ehlers, Koop Lammertsma

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Reaction pathways for the formation of zirconocene phosphinidene complex Cp2Zr(PR3)PR from Cp2ZrCl2 and LiH and LiPRH and its reactivity to 1,2-dichloroethane are explored with density functional theory using model structures that are devoid of substituents. After the initial Cp2Zr(Cl)PH2 is generated with LiPH 2 reaction with LiH is likely to eliminate HCl in a single step to give directly the 16-electron complex Cp2ZrPH, which is stabilized by the PH3 phosphine ligand. The intermediate formation of a phosphine hydride complex, Cp2Zr(H)PH2 resulting from hydride substitution, is unlikely both on the basis of unfavorable reaction energies and calculated 31P NMR chemical shifts that indicate that such a species cannot have been observed experimentally. It is likely that a diphosphine complex, Cp2Zr(PH2)2, results on using an excess of the lithium phosphide, which on H-transfer gives directly the phosphine-stabilized phosphinidene complex. The reactivity of this species is dominated by the release of its stabilizing phosphine ligand to give a highly reactive 16-electron phosphinidene complex, Cp2ZrPH, which reacts with 1,2-dichloroethane after coordination to one of the chlorine atoms in two asynchronous metathesis steps to the three-membered phosphirane ring. In this process, ZrCl2 is reformed enabling its recycling to regenerate the phosphinidene complex. This study highlights the special reactivity of the 16-electron Cp2ZrPH and suggests that related complexes may be generated similarly, thereby expanding the synthetic potential of these nucleophilic reagents.

Original languageEnglish
Pages (from-to)5517-5524
Number of pages8
JournalJournal of Organometallic Chemistry
Volume690
Issue number24-25
DOIs
Publication statusPublished - 1 Dec 2005
Externally publishedYes

Keywords

  • Catalysis
  • DFT calculations
  • Phosphinidenes
  • Phosphiranes
  • Zirconium complexes
  • σ-Bond metathesis

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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