Ueber gemischte Gruppe 14-Gruppe 14-Bindungen. IV. Hexa-p-tolylethan-Analoga p-Tol6Sn2, p-Tol6PbSn und p-Tol6Pb2: Darstellung, Homoeotype Structuren, NMR-Kopplungen und Valenzschwingungen

Article abstract of DOI:10.1016/0022-328X(91)80135-7

p-Tol6PbSn has been synthesized by reaction of p-Tol3PbLi with p-Tol3SnI in THF/ether (1:2) at -78 deg C.The crystal structures of p-Tol4Pb (I<*>) and of p-Tol6Sn2, p-Tol6PbSn and p-Tol6Pb2 have been determined.The three dinuclear compounds crystallize not strictly isomorphous.They exhibit the same space group (R<*>) and rather similar unit cell dimensions.Yet according to the solvent of crystallization, two types with differing atomic position parameters can be distinguished ( homoeotypism with differences of parameters in the definition of Laves).In both types, the individual molecules have a chiral C₃-symmetric conformation and the non-chiral unit cell encloses both enantiomers.The metal-metal distances are Sn-Sn = 2.777(1), Pb-Sn = 2.813(2) and Pb-Pb = 2.851(1) Angstroem, NMR (13C, 119Sn, 207Pb) and Raman data are given (¹J(119Sn- 119Sn) = 4570, ¹J(119Sn-207Pb) = 3640 Hz; ν(Sn-Sn) = 131, ν(Pb-Sn) = 114, ν(Pb-Pb) = 105 cm^-1).