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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.

The acid-catalyzed polycondensation of ferrocenylphenylcarbinol Ic under controlled, mild reaction conditions gives rise to the formation of low-molecular, ferrocene-containing polymeric ethers, to which, on the basis of elemental analysis, infrared and NMR spectro-scopic data, the structure IIIf is assigned. Monomeric ether IIIc is isolated in addition under these conditions. In the presence of Lewis acids at elevated temperatures, ethers Illf continue to react, with the elimination of the ether bridge, to give polymers identical with the previously reported oxygen-free compounds IIc, which were obtained directly from Ic under more rigorous conditions. In the previous work, polymers IIIf containing an ether group were postulated as intermediates but were not isolated. The observed formation of such polymers under the present experimental conditions, coupled with their successful post-condensation to IIc, is thus in accord with the earlier mechanistic implications.

No abstract

The self‐condensation of the ferrocenyl Mannich base, N,N‐dimethylaminomethylferrocene, in the presence of a ZnCl2HCl catalyst system in the melt phase leads to soluble polymers containing ferrocenylene units interlinked by methylene groups. The crude condensation products exhibit number‐average molecular weights in the range 4000–8000. Elemental and infrared spectroscopic analyses as well as viscometric data show the structure to be essentially identical with that of the polymer derived from hydroxymethylferrocene described in an earlier communication. The optimum molar ratio of the reactants (Mannich base, ZnCl2, and HCl) is 2:1:2. Dimethylammonium tetrachlorozincate has been isolated as by‐product, and an intermediary complex composed of Mannich base, ZnCl2, and HCl in the same 2:1:2 ratio has been intercepted during the polycondensation. Some mechanistic inferences are discussed.