The lead-tin compounds o-Tol6PbSn. o-Tol3PbSnPh3 and MeS3PbSnPh3 have been synthesized from Li and halide precursors in THF/ether at low temperatures. The crystal structures of the S4 symmetric o-Tol4Pb and of the three isomorphous title compounds have been determined (d(Sn-Sn) 2.883 (1), d (Pb-Sn) 2.845 (2), d (Pb-Pb) 2.895 (2) angstrom). The long Sn-Sn distance is in accordance with the Raman data for the pairs of p-Tol6/o-Tol6 substituents (nu(Sn-Sn) 131/123, nu(Pb-Sn) 114/114. nu(Pb-Pb) 105/103 cm-1). The sequence of the Sn-119 and Pb-207 chemical shifts shows clearly a polarity Pb(delta-)-Sn(delta+ for all lead-tin compounds investigated. The 1J(Sn-119-Pb-207) and 1J(Sn-119-Sn-119) couplings of identically substituted compounds depend upon another in a nearly linear manner.
Morris; Byerly; Selwood, Journal of the American Chemical Society, 1942, vol. 64, p. 1728