Ferrocene-containing Polymers. IX. Polycondensation of Ferrocene with Formaldehyde

Abstract

The Lewis acid-catalyzed polycondensation of ferrocene with formaldehyde or its dimethyl-acetal gives rise to the formation of soluble, novolac-type polymers comprising ferrocenylene units interlinked by methylene bridges. In contrast to earlier work performed by other investigators in liquid hydrogen fluoride or sulfuric acid media, where only non-polymeric products were described, propagation is accomplished in the present case by condensing the reactants in a closed system in bulk at temperatures up to 170°C. The resulting polymers, with Mn values up to 4000 (unfractionated), are shown by elemental and spectroscopic analyses and viscometric data to be essentially identical with the previously reported polycondensation products of N, N-dimethyl-aminomethylferrocene with ferrocene. Infrared spectroscopy shows the intralinear substitution to be predominantly homoannular, which is expected as a result of the electronic effects exercised by the methylene substituent. Under appropriate conditions, additional methylene groups can be incorporated into the polymer, giving rise to double-bridged segments and inter-chain bridging. Strongly crosslinked polymers are obtained if excess aldehydic reactant is employed at temperatures in the 170–185°C range.

gem-Diferrocenylalkane derivatives. Acid-catalyzed condensation of ferrocene with methyl levulinate and 5-hydroxy-2-pentanone

“…From Methyl 4,4-Diferrocenylpentanoate (5). A solution of methyl 4,4-diferrocenylpentanoate (3.4 g, 7.0 mmol) in 15 ml of dry tetrahydrofuran was added dropwise with stirring during 15 min to a solution of 0.27 g (7.0 mmol) of lithium aluminum hydride in 25 ml of ether. The mixture was heated under reflux with stirring for 80 min.…”

“…The acid-catalyzed condensation of ferrocene with aldehydes and ketones is complex and leads to several types of compounds. [1][2][3][4][5][6][7][8][9][10] In the present study a convenient synthesis was sought for diferrocenylmethane derivatives 1, in ŵhi ch R contains a reactive functional group. The acid-catalyzed ferrocene-ketone condensation, although presenting a potentially simple route to 1, suffers the major disadvantage of providing very low yields under known reaction conditions.…”