6533b7defe1ef96bd1275afb

RESEARCH PRODUCT

Über gemischte Gruppe 14—Gruppe 14-Bindungen

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Abstract p-Tol6PbSn has been synthesized by reaction of p-Tol3PbLi with p-Tol3SnI in THF/ether (1:2) at −78°C. The crystal structures of p-Tol4Pb (I 4 ) and of p-Tol6Sn2, p-Tol6PbSn and p-Tol6Pb2 have been determined. The three dinuclear compounds crystallize not strickly isomorphous. They exhibit the same space group (R 3 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) A. 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).