Reinvestigation of the Rosenberg Synthesis of Silyleneferrocenylene Polymers

Reinvestigation of the original Rosenberg synthesis of silyleneferrocenylene polymers shows that no condensation−polymerization occurs in the reaction of dilithioferrocene ( 1 ) and dimethyldichlorosilane ( 2a ) in the THF/hexane solvent mixture specified. These experimental conditions result in the direct formation of [1](dimethylsilylene)ferrocenophane ( 3a ). Differing work up conditions result in differing products, and those reported produce a mixture of ferrocenylene- and ferrocenylsiloxanes. The addition of 1 to 2a in THF also produced the ferrocenophane as the most abundant product, whereas the reverse addition of 2a to 1 resulted in the formation of ferrocenophane at low temperatures and a polymeric material at high temperatures. Similar results were obtained upon replacing 2a by diphenyldichlorosilane ( 2b ), suggesting that the results are general.