2-Pyridylmetallocenes, Part IX. Sulphur-Substituted 2-Pyridylferrocene: Synthesis and Reactivity towards Pt(II) and Hg(II)

Thio-substituted 2-pyridylferrocenes [CpFe{C₅H₃(X)(C₅H₄N)}] (X = SOTol, 3; SMe, 5) were prepared from [CpFe(C₅H₄R)] (R = SOTol, 1; 2-C₅H₄N, 2) in moderate yields. The reactions of 3 and 5 with [PtCl₂(DMSO)₂] yielded the binuclear N, S chelated complexes [CpFe{C₅H₃(X)(C₅H₄N)}-(к-N,S)-PtCl₂] (X= SOTol, 4, SMe, 6), while the reaction of 5 with Hg(OAc)₂/LiCl led to cyclomercuration with generation of [CpFe{C₅H₂(SMe)(C₅H₄N)(HgCl)}], 7. The crystal structures of 6·CH₂Cl₂ and 7 were determined. The structure of 6 showed a weak intramolecular Fe…Pt interaction and several weak intermolecular interactions involving all Cl atoms. Weak intermolecular interactions between Hg and S atoms in the cyclomercurated 7 led to a tetrameric structure involving a Hg₂S₂ ring.