Stereochemical activity of the metal-centered lone electron pair in group 14 metallocenes. Crystal structure of the linear sandwich complex [C5(iPr)3H2]2Pb.

Stereochemically active valence electrons are not present in the structure of [C5(Pri)3H2]2Pb, which, like [C5Me4(SiMe2But)]2Pb, possesses parallel cyclopentadienyl rings. There are no close intramolecular contacts that force the rings to be parallel; the structure is consistent with the lack of a strong electronic preference for bending in heavy group 14 metallocenes.