A new twist on an old molecule: a rotameric isomer of bis(pentafluorophenyl)mercury

Zhifang Guo, Ryan Huo, Yu Qing Tan, Niko T. Flosbach, Nicole Wang, Céline Leonhardt, Aron Urbatsch, Glen B. Deacon, Peter C. Junk, Ekaterina I. Izgorodina, Victoria L. Blair

Research output: Contribution to journalArticleResearchpeer-review


Suspending crystals of bis(pentafluorophenyl)mercury [Hg(C6F5)2] (1a) in a saturated n-hexane solution for a prolonged period results in transformation into the new polymorph [Hg(C6F5)2] (1 b) monoclinic P21/n, a = 11.7060(3) Å, b = 7.8531(2) Å, c = 13.5429(4) Å, β = 107.247(3)°, V = 1189.00(6) Å3. The C-Hg-C angle in 1 b is 177.10(11)° and the pentafluorophenyl rings are rotated 74.6(1)° to each other in comparison to 1a, the form known for 50+ years, which has a rotation angle of 58.0(2)°. Polymorph 1 b could also be obtained by crystallization from chloroform, or a CHCl3/n-hexane (1:1) mixture at −20 °C, or by seeding with a crystal of 1 b. Theoretical calculations suggest that the barrier to rotation is low.

Original languageEnglish
Pages (from-to)2947-2958
Number of pages12
JournalJournal of Coordination Chemistry
Issue number17-20
Publication statusPublished - 16 Nov 2021


  • crystallization
  • Mercury
  • pentafluorophenyl
  • rotation energies

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