Synthesis and structure of trialkyltantalum complexes stabilized by aminopyridinato ligands

Awal Noor, Winfried Kretschmer, Rhett Kempe*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

16 Citations (Scopus)

Abstract

(4-Methylpyridin-2-yl)(trimethylsilyl)amine (1), (6-methylpyridin-2-yl)(trimethylsilyl)amine (2), and (2,6-diisopropylphenyl)(pyridin-2-yl)amine (3) were deprotonated and used as ligands to synthesize trialkyltantalum complexes. The reaction of 2 equiv. of 1 or 2 with pentabenzyltantalum afforded tribenzyltantalum(v) complexes by toluene elimination. Analogous reaction using 3 failed. Lithiation of 3 followed by the reaction with tribenzyltantalum dichloride gave rise to the corresponding tribenzyl complex. Other alkyltantalum complexes stabilized by this ligand environment can be prepared by treating tantalum pentachloride with 2 equiv. of lithiated 3 to form a bis(aminopyridinato)tantalum trichloride. The reaction of this trichloride with 3 equiv. of alkyllithium compounds like methyllithium affords the corresponding trialkyltantalum complexes. X-ray diffraction studies of four of the synthesized complexes were carried out. They adopt two different coordination environments, either slightly distorted capped octahedrons (sterically less demanding aminopyridinato ligands) or pentagonal bipyramids (bulkier aminopyridinato ligands). The alkyl species were surprisingly stable at elevated temperatures and no formation of mixed alkyl/alkyhdene complexes was observed. Alkyl cation formation and the behaviour of a selection of these compounds in olefin polymerization were explored.

Original languageEnglish
Pages (from-to)2683-2689
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Issue number13
DOIs
Publication statusPublished - 3-Jul-2006

Keywords

  • amido ligands
  • aminopyridinato ligands
  • N ligands
  • olefin polymerization
  • tantalum
  • METAL-CARBON BONDS
  • X-RAY STRUCTURES
  • CRYSTAL-STRUCTURE
  • COORDINATION CHEMISTRY
  • BENZAMIDINATO COMPLEXES
  • TANTALUM
  • NIOBIUM
  • IMIDO
  • ABSTRACTION
  • METHYLIDENE

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