Synthesis and Characterization of a Stable Organolead(II) Compound:  Bis[2-(N,N-dimethylaminomethyl)ferrocenyl]lead

The reaction of {C,N-[Fe(η5-C5H5)(η5-C5H3(CH2NMe2)-2)]}Li, [FcN]Li, with PbCl2 yields the new stable tetracoordinated diorganolead(II) compound [FcN]2Pb, 1, as a mixture of two diastereomers. In the solid state only the meso-diastereomer exists, which crystallizes in two polymorphs, P21/c and C2/c. The ratio of meso/rac-diastereomers in solution is solvent- and temperature-dependent, consistent with an intermolecular exchange between diastereomers. This is the very first observation of such an exchange for lead(II) compounds. An intramolecular exchange process is responsible for equivalency of both FcN groups in solution. The NMR measurements of 1 revealed the authentic spectroscopical data: 13C−207Pb coupling constants in solid-state 13C NMR spectra.