SYMMETRIZATION REACTION OF MERCURATED FERROCENYLIMINES - X-RAY CRYSTAL-STRUCTURE OF HG((ETA(5)-C5H5)FE(ETA(5)-C5H3CPH=NC6H4-4-BR))(2)]

The symmetrization reaction of mercurated anils of benzoylferrocene 1 was easily achieved by refluxing 1 and PPh3 in CHCl3 solution, and aff orded the symmetrized products [Hg{(eta(5)-C5H5)Fe(eta(5)-C5H3CPh=NAr) }(2)] (Ar = a variety of substituted phenyls and beta-naphthyl) 2. Dur ing the reaction the organometallic complex salts [RHgPPh3]Cl formed; this can disproportionate to give the symmetrized products. The molecu lar structure of [Hg(eta(5)-C5H5)Fe(eta(5)-C5H3CPh=NC6H4-4-Br)}(2)] ha s been determined by single-crystal X-ray analysis. It crystallizes in the triclinic space group P (1) over bar, with a = 13.001(4), b = 13. 029(2), c = 12.236(2)Angstrom, alpha = 103.00(1), beta = 104.10(2), ga mma = 78.86(2)degrees and Z = 2. Refinement led to R = 0.027 (Rw = 0.0 37) using 3271 unique reflections with I > 3 sigma(1). The distance be tween N(2) and Hg is 2.981(6)Angstrom, shorter than the sum of van der Waals radii of N and Hg (3.05-3.15 Angstrom), indicating an intramole cular coordination of N(2) and Hg. The 1(H) NMR spectra of [Hg{(eta(5) -C5H5)Fe(eta(5)-C5H3CPh=NAr)}(2)] (Ar = C6H4-2-Cl and 2-naphthyl) show that both compounds exist as rotamers in solution.