Chain branching during the polycondensation of isophthalic aldehyde and 1,1′‐diacetylferrocene by the Claisen–Schmidt reaction

Abstract

N‐methyl‐2‐pyrrolidone‐soluble ferrocene‐containing polychalcones, which are promising as a platform for the formation of ferromagnetic coatings after pyrolysis in an inert atmosphere is synthesized through the polycondensation of isophthalic aldehyde and 1,1′‐diacetylferrocene by the Claisen–Schmidt reaction. The structure and the molecular weight distribution of the polychalcones is characterized by NMR, IR spectroscopy, and size exclusion chromatography. It is shown that the formation of polychalcones is accompanied by chain branching via the Michael reactions and the aldol‐croton condensation. The structure of the linear fragments of the polychalcone chains is simulated with a tailored low‐molecular model compound, that is 1,3‐bis(3‐ferrocenyl‐1‐propen‐2‐one)benzene, which is characterized by the NMR and IR spectroscopy as well as the X‐ray diffraction analysis. The obtained results indicate an increasing tendency for polychalcone chain branching with the temperature growth during the Claisen–Schmidt reaction. The weight loss and the increase in magnetization under the conditions of pyrolysis of polychalcones at different temperatures is studied. The assumptions regarding the possible mechanisms of thermal destruction of ferrocene‐containing macromolecules are put forward.