Symmetrization reaction of mercurated ferrocenylimines. X-ray crystal structure of [Hg{(η5-C5H5)Fe(η5-C5H3CPh=NC6H4-4-Br)}2]

Article abstract of DOI:10.1016/S0022-328X(96)06602-8

The symmetrization reaction of mercurated anils of benzoylferrocene 1 was easily achieved by refluxing 1 and PPh₃ in CHCl₃ solution, and afforded the symmetrized products [Hg{(η⁵-C₅H₅)Fe(η⁵-C₅H₃CPh=NAr)}₂] (Ar = a variety of substituted phenyls and β-naphthyl) 2. During the reaction the organometallic complex salts [RHgPPh₃]C1 formed; this can disproportionate to give the symmetrized products. The molecular structure of [Hg(η⁵-C₅H₅)Fe(η⁵-C₅H₃CPh=NC₆H₄-4-Br)}₂] has been determined by single-crystal X-ray analysis. It crystallizes in the triclinic space group P1, with a = 13.001(4), b = 13.029(2), c = 12.236(2)A, a = 103.00(1), β = 104.10(2), γ = 78.86(2)° and Z = 2. Refinement led to R = 0.027 (Rw = 0.037) using 3271 unique reflections with I > 3σ(I). The distance between N(2) and Hg is 2.981(6) A, shorter than the sum of van der Waals radii of N and Hg (3.05-3.15 A), indicating an intramolecular coordination of N(2) and Hg. The ¹H NMR spectra of [Hg{(η⁵-C₅H₅)Fe(η⁵-C₅H₃CPh=NAr)}₂] (Ar = C₆H₄-2-C1 and 2-naphthyl) show that both compounds exist as rotamers in solution.