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 t etrahydrofuran with the appropriate reagent LiR, where R = (PhMe2Si)(3 )C, (Me3Si)(3)C, or (MeOMe2Si)(Me3Si)(2)C, and their crystal structure s 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)}C l](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, t here are (relatively weak) intramolecular MeO...M interactions in addi tion. 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 ha ve been structurally characterized, and [Sn{C(SiMe2Ph)(3)}Cl](2) is on ly the second solvent-free mono(alkyl)tin(II) compound. All of the com pounds are yellow and air-sensitive in the solid and in solution, and the lead compounds are readily decomposed in solution by exposure to d aylight.