On the primary structure of polysilenes and polygermenes†
Despite the long history and prominence of addition polymerizations in alkene chemistry, addition polymerizations of the heavier main group analogs of alkenes are in their infancy. Herein, the detailed structural and end group analyses of polysilenes (polycarbosilanes) and polygermenes (polycarbogermanes) derived from the anionic polymerization of kinetically-stabilized silenes and germenes, respectively, are reported. The end groups were identified using ESI-TOF mass spectrometry. Careful examination of the 13C–1H HSQC NMR spectra of both polymers confirmed the regular, alternating structure consistent with an addition polymerization with no significant amount of intramolecular rearrangement or back-biting. These results are in contrast to what has been observed during the synthesis of the analogous polyphosphenes.