Carbon-Hydrogen Bond Activation by Transition Metal Complexes. Oxidative Addition of Alkyl Methacrylate to Ruthenium. The Structure of Hydrido(2-n-butoxycarbonylpropenyl-C1,O)tris(triphenylphosphine)ruthenium(II)

Sanshiro Komiya, Takashi Ito, Martin Cowie, Akio Yamamoto*, James A. Ibers

*Corresponding author for this work

Research output: Contribution to journalArticle

110 Scopus citations

Abstract

Alkyl methacrylate reacts with dihydridotetrakis(triphenylphosphine)ruthenium(II) via vinylic C-H bond cleavage to give hydrido(2-alkoxycarbonylpropenyl-C1,O)tris(triphenylphosphine)ruthenium(II), RuH(CH=C(CH3)C(O)OR)- (PPh3)3, accompanied by formation of an equimolar amount of alkyl isobutyrate per mole of the dihydrido complex. A hydridoalkenyl-type structure for the complex was proposed on the basis of chemical reactions, such as the formation of methyl cis-(β-deuteriomethacrylate on treatment of the complex with DC1, and methylation at the β-position of alkyl methacrylate on treatment with methyl iodide. The low v(C═O) band (~1580 cm-1) in its ir spectrum, the presence of a hydride signal in the 1 H NMR spectrum, and the 31 P{1 H} NMR spectrum characteristic of meridional octahedral configuration support the proposed structure. An x-ray study confirmed the structure of hydrido(2-n-butoxycarbonylpropenyl-C1,O)tris(triphenylphosphine) ruthenium(II). This compound crystallizes from tetrahydrofuran-diethyl ether in the space group C2h6-C2/c with a = 29.691 (8) Å, b = 21.865 (5) Å, c = 21.245 (6) Å, β = 122.26 (1)°, and Z = 8. Based on 4801 unique reflections with FO2 ≥ 3σ(FO2) full-matrix, least-squares refinement led to agreement indices (on F) of R = 0.067 and Rw = 0.111. The structure consists of discrete molecules of the complex in which the ruthenium atom is six-coordinate with distorted octahedral geometry. Three coordination sites are occupied by the phosphine ligands in a meridional arrangement. The alkyl methacrylate ligand is bidentate, bonded to the ruthenium atom via the vinylic carbon and the carboxyl oxygen atoms forming a C-O five-membered ring. The vinyl carbon atom is trans to a phosphine ligand and the oxygen atom is trans to the hydrido ligand. The terminal three carbon atoms of the n-butyl group of the n-butyl methacrylate ligand are disordered making a satisfactory description of their positions difficult. Some relevant metric parameters in the complex are: Ru-C(1), 2.061 (10) Å; Ru-O(1), 2.246 (7) × C(1)-C(2), 1.368 (15) Å; C(2)-C(4), 1.442 (15) Å; C(4)-O(1), 1.254 (12) Å; O(1)-Ru-C(1), 75.6 (4)°; Ru-C(1)-C(2), 117.8 (8)°; C(1)-C(2)-C(4), 113.4 (10)°; C(2)-C(4)-O(1), 121.2 (11)°; and C(4)-O(1)-Ru, 111.6 (7)°.

Original languageEnglish (US)
Pages (from-to)3874-3884
Number of pages11
JournalJournal of the American Chemical Society
Volume98
Issue number13
DOIs
StatePublished - Jun 1 1976

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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