Synthesis, spectroscopy, structure, and reactivity of bis-azapentadienyl-ruthenium-phosphine complexes

  • John R. Bleeke
  • , Meghan Stouffer
  • , Nigam P. Rath

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

We report the synthesis, spectroscopy, structure, and reactivity of the first examples of bis-azapentadienyl-ruthenium complexes. The parent compound, [(1,2,3-η3)-(5-tert-butylazapentadienyl)]2Ru(PPh3)2 (1), is produced by reacting Cl2Ru(PPh3)3 with two equivalents of potassium tert-butylazapentadienide. Treatment of 1 with CNCMe3, P(OMe)3, PMe3, or PEt3 (L) in THF at room temperature yields single-ligand substitution products [(1,2,3-η3)-(5-tert-butylazapentadienyl)]2Ru(PPh3)(L) (2, L = CNCMe3; 3, L = P(OMe)3; 4, L = PMe3; 5, L = PEt3), and the double-ligand substitution product, [(1,2,3-η3)-(5-tert-butylazapentadienyl)]2Ru(PEt3)2 (6). Other double-ligand substitution products, [(1,2,3-η3)-(5-tert-butylazapentadienyl)]2Ru(L)2 (7, L = PMe3; 8, L = P(OMe)3), are obtained when 1 is treated with PMe3 or P(OMe)3 in THF at reflux. Compounds 7 and 8 exist in solution as equilibrium mixtures of two structural isomers. Electron-rich compounds 6 and 7 react with triflic acid to generate dicationic products,{[(1,2,3-η3)-(CH2CHCHCHN(H)(CMe3)]2Ru(L)2}2+(-O3SCF3)2 (9, L = PEt3; 10, L = PMe3), in which both azapentadienyl nitrogen atoms have been protonated. All of the compounds reported herein have been characterized by NMR spectroscopy, and the structures of 2, 3, 4, 6, and 9 have been confirmed by single-crystal X-ray diffraction.

Original languageEnglish
Pages (from-to)11-22
Number of pages12
JournalJournal of Organometallic Chemistry
Volume781
DOIs
StatePublished - Apr 1 2015

Keywords

  • Azapentadienyl-metal complexes
  • Heteropentadienyl ligands
  • Ruthenium

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