REINVESTIGATION OF THE ROSENBERG-SYNTHESIS OF SILYLENEFERROCENYLENE POLYMERS

Reinvestigation of the original Rosenberg synthesis of silyleneferroce nylene polymers shows that no condensation-polymerization occurs in th e reaction of dilithioferrocene (1) and dimethyldichlorosilane (2a) in the THF/hexane solvent mixture specified. These experimental conditio ns result in the direct formation of [1](dimethylsilylene)ferrocenopha ne (3a). Differing work up conditions result in, differing products, a nd those reported produce a mixture of ferrocenylene- and ferrocenylsi loxanes, The addition of 1 to 2a in THF also produced the ferrocenopha ne 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 obtai ned upon replacing 2a by diphenyldichlorosilane (2b) suggesting that t he results are general.