The X-ray crystal structures of [Hg(C6F4OH-p)2OH2] and [Hg(C6H4OMe-p)(O2CC6F4OMe-p)] – Factors influencing supramolecular Hg–O interactions

An X-ray crystal structure has shown that the previously reported bis(p-hydroxytetrafluorophenyl)mercury crystallises as a monohydrate [Hg(C6F4OH-p)2(OH2)] exhibiting rare coordination of water to a diorganomercurial. The stereochemistry of the three-coordinate mercury is T-shaped with the water coordinated perpendicular to the near linear C–Hg–C unit. The molecules are linked in chains by hydrogen bonding between the hydroxy groups, and the chains into layers by hydrogen bonding between the water oxygen and an OH group. Thermogravimetric analysis shows two water molecules are eliminated together, both the coordinated water and one formed through condensation of the linked –OH groups. In [Hg(p-MeOC6H4)(O2CC6F4OMe-p)], molecules with a near linear strongly bonded C–Hg–O arrangement are observed. These are linked into a linear polymer through Hg–O (carboxylate) bridges giving alternate four-membered and eight-membered rings giving mercury overall square planar stereochemistry.