Chelation versus cyclometalation in a cationic Dppn-RhI complex - A unique rearrangement of norbornadiene via C-H activation of the pyridazine ring

Reto Dorta, Leonid Konstantinovski, Linda J.W. Shimon, Yehoshoa Ben-David, David Milstein

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The tetradentate ligand 3,6-bis(2-pyridyl)pyridazine (dppn) was treated with cationic RhI precursors. The mononuclear complexes [Rh(dppn)(NBD)]BF4 (1) and [Rh(dppn)(COD)]BF4 (5) were obtained in quantitative yield when treating dppn with [Rh(NBD)2]BF4 or [Rh(COD)2]BF4 respectively. Treatment of 1 with a second equivalent of the metal precursor [Rh(NBD)(CH3CN)2]BF4 led to the dinuclear complex [Rh2(dppn-H)(NBD)(η-C7H9) (CH3CN)2](BF4)2 (2) [dppn-H = μ-C4HN2(C5H4N)2-3, 6], a mixed RhI-RhIII complex. This complex arises from C-H activation of the pyridazine ring, followed by a unique rearrangement of the NBD ligand. Compound 2 was also obtained directly by treating dppn with 2 equiv. of [Rh(NBD)(CH3CN)2]BF4. The complex [Rh2(dppn-H)(NBD)(η1-C7H9) (CH3OH)2(CH3CN)](BF4)2 (4) was obtained by dissolving 2 in methanol. Full characterization of compounds 1, 4 and 5 included an investigation by 1H-15N GHMBC NMR spectroscopy and single-crystal X-ray structures of 1 and 4.

Original languageEnglish
Pages (from-to)70-76
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Issue number1
Publication statusPublished - Jan 2003



  • C-H activation
  • Mono- and dinuclear complexes
  • Rearrangement of norbornadiene
  • Rhodium complexes
  • X-ray structure

ASJC Scopus subject areas

  • Inorganic Chemistry

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