Chemistry of (η-Phenoxide)Cr(CO)3Ligands

Joseph A. Heppert, Timothy J. Boyle, Fusao Takusagawa

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

6-Phenol) tricarbonylchromium complexes are conveniently converted to [(η6-phenoxide)Cr(CO)3]- species on treatment with aqueous base. The phenoxide chromium anions, which are readily isolated as crystalline tetraethylammonium salts, react with main-group electrophiles ((p-tol)SO2Cl or CF3COCl) to produce new sulfonate-and carboxylate-substituted arene chromium complexes. Similar reactions between the phenoxide anions and metal electrophiles (CpFe(CO)3+ or Cp2ZrCl2) result in electron-transfer reactions that consume the starting arene complexes. Transition-metal complexes bearing (η-phenoxide)Cr(CO)3 ligands are conveniently prepared through alcoholysis reactions with metal alkoxide and metal dimethylamide precursors. An X-ray crystallographic study of Cp2Zr{(η-OC6H5)Cr(CO)3}2 was carried out. For 1403 unique intensity data collected by using Cu Kα radiation in a θ–2θ scan procedure, the space group for the molecule was determined to be Pnma with unit cell parameters a = 15.023 (3) Å, b = 21.864 (5) Å, and c = 8.073 (2) Å. The refinement converged to an R(F) of 0.078 and an RW(F) of 0.089. The molecule shows general structural features common to other bent zirconocene and π-arene chromium complexes but shows some unexpected features associated with the Zr-aryloxide bonding. Little evidence is found for either steric interactions between the (η-OC6H5)Cr(CO)3 units or for Zr-O π bonding. The O-arene bond does show a small degree of multiple-bond character. This observation is supported by the deviation of the O-C arene vector from the least-squares arene plane, suggesting that a small degree of a cyclohexadienone resonance form is contributing to Zr-arene bonding.

Original languageEnglish
Pages (from-to)461-467
Number of pages7
JournalOrganometallics
Volume8
Issue number2
DOIs
StatePublished - Feb 1989

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