H and TC NMR studies of pentachlorocyclopentadienyl (2,4,6-tri-tert-butylphenyl) mercury

Pentachlorocyclopentadienyl (2,4,6-trit-tert-butylphenyl) and mercury, l, has been prepared by reacting equimolar amounts of bis (2,4,6-tri-tert-butylphenyl) mercury, 2, and bis (pentachlorocyclepentadienyl) mercury, 3, in methylene chloride. The formation of l by this simple exchange reaction was rather surprising, since examination of solid state structure of 2 had suggested that this molecule ought to be too sterically hindered to react via simple exchange, especially in methylene chloride. Compound l is of interest because of the C5Cl5 ligand might be expected to exhibit fluxional behavior (i.e., 1,2-sigmatropic rearrangement) both in solution and in the solid state. Preliminary TVCl-NQR data (N. Weiden and G. Wulfsbert, unpublished results) has confirmed fluxionality in the solid state and suggests an activation energy on the order of 23 kJ/mole for the rearrangement. Solution TC-NMR data will be presented that also confirms fluxionality of the C5Cl5 group in solution. Preten, ZZHg and solid state TC-NMR data on l will also be discussed.