Phenyl derivatives of mercury functionalised in the 2-position with either a formyl or a vinyl group. Crystal structures of Hg[C6H4(CHO)-2]Cl and Hg[C6H4(CHCH2)-2]2

A convenient preparation of Hg[C6H4(CH2OH)-2]Cl (1) involves treatment of dilithiated benzyl alcohol with HgCl2. 1 is smoothly oxidised to Hg[C6H4(CHO)-2]Cl (2) by reaction with pyridinium chlorochromate (PCC). The crystal structure of 2 reveals a two coordinate linear arrangement at mercury supplemented by weaker interactions with the aldehyde oxygen atoms both intramolecularly and intermolecularly. Treatment of 2 with NaI effects symmetrisation with the formation of Hg[C6H4(CHO)-2]2 (3). Reaction between 3 and the Wittig reagent Ph3PCH2 results in the formation of Hg[C6H4(CHCH2)-2]2 (4). The crystal structure of 4 has been determined.