The structure of pentachlorocyclopentadienylphenylmercury(II) in the solid state and in solution; the effect of X-ray absorption and crystal decay on molecular geometry parameters

Abstract

The structure of pentachlorocyclopentadienylphenylmercury(II), Hg(C₅Cl₅)Ph, has been determined by single-crystal X-ray diffraction. The cyclopentadienyl ring is σ bonded, and the ring and the vinylic chlorine atoms are essentially coplanar. The structure provides no evidence for secondary Cl→Hg bonding. The ¹³C n.m.r. spectrum shows that, in solution, the cyclopentadienyl ring is fluxional; the sequence of mobilities is Hg(C₅H₅)₂ > Hg(C₅H₅)Cl ∼ Hg(C₅Cl₅)Ph > Hg(C₅Me₅)₂.