Trifluoromethylsubstituierte Plumbane. Synthese, Eingeschaften und NMR-Spektren der Verbindungen (CF3)nPbR4-n (n = 1-3) und (CF3)nPbR3-nX (n = 1, 2; R = Me, Et; X = Hal)

Article abstract of DOI:10.1016/0022-328X(92)88006-5

Trifluoromethylated derivatives of lead, (CF3)nPbR4-n (n = 1-3; R = CH3, C2H5), have been prepared by a stepwise halide/CF3 exchange from (CF3)nPbR3-nX (n = 0-2) and donor-stabilized (CF3)2Cd.Upon treatment of CF3PbR3 and (CF3)2PbR2 with halides under mild conditions, selective cleavage of the Pb-C(H) bond and formation of the corresponding alkyl(trifluoromethyl)haloplumbanes were achieved, whereas with (CF3)3PbMe only (CF3)2PbMeX was obtained.The direct exchange of alkyl and trifluoromethyl groups was observed for the systems PbR4/(CF3)nE (E = Hg, Ge, Sn), (CF3)4Sn being the most efficient CF3 transfer reagent.All compounds were characterized by vibrational, mass and multinuclear NMR spectroscopy.The NMR coupling constants ⁿJ(207Pb-E) (E = 19F, 1H, 13C), which vary strongly with solvents and substituents, have been determined along with their absolute sings.Linear correlations found between ¹J(207Pb-CF3) and ²J(207Pb-F) or ²J(207Pb-F) and ²J(119Sn-F) of homologous trifluoromethylated stannanes, respectively.