Synthesis and crystal structures of the compounds [Sn{C(SiMe2Ph)3}Cl]2, [Pb{C(SiMe3)3}Cl]3, and [M{C(SiMe3)2(SiMe2OMe)}Cl]2 (M = Sn or Pb)

The title compounds have been made by treatment of SnCl2 or PbCl2 in tetrahydrofuran with the appropriate reagent LiR, where R = (PhMe2Si)(3)C, (Me3Si)(3)C, or (MeOMe2Si)(Me3Si)(2)C, and their crystal structures determined. In all four compounds, as in the previously reported [Pb{C(SiMe2Ph}(3))Cl](2), the metal atoms are linked by bridging Cl atoms, unsymmetrically except in the case of the trimeric [Pb{C(SiMe3)(3)}Cl](3) (in which the six-membered ring has a distorted boat form). In [M{C(SiMe3)(2)(SiMe2OMe)}Cl](2), M = Sn or Pb, which are isomorphous, there are (relatively weak) intramolecular MeO...M interactions in addition. The compounds [Pb{C(SiMe2Ph)(3)}Cl](2) and [Pb{C(SiMe3)(3)}Cl](3) are the only known sigma-bonded mono(organo)lead(II) compounds to have been structurally characterized, and [Sn{C(SiMe2Ph)(3)}Cl](2) is only the second solvent-free mono(alkyl)tin(II) compound. All of the compounds are yellow and air-sensitive in the solid and in solution, and the lead compounds are readily decomposed in solution by exposure to daylight.