Synthesis of Ferrocene-Containing Schiff Bases Based on 3-Aminopropyltriethoxysilane Oligomers for Covalent Modification of Glass Surfaces and Creation of Soft Magnetic Materials

Abstract

A ferrocene-containing oligoorganosiloxane with a number-average degree of polymerization of 8.8 and a number-average molecular weight of 3200 is synthesized by hydrolytic condensation of 3-aminopropyltriethoxysilane followed by chemical modification of the resulting oligomer with acetylferrocene. Its structure is characterized by MALDI-TOF, NMR and IR spectroscopy. ¹H NMR spectroscopy shows the predominance of more thermodynamically stable units containing anti-configuration Schiff bases. Using IR spectroscopy as well as experimental determination of surface energy and its polar (acid–base) and dispersion components, the covalent immobilization of ferrocene-containing oligoorganosiloxane on a glass surface after heating at 110°C is shown. The formed coating provides hydrophobization, acid–base indifference of the glass surface and serves as a precursor for the formation of magnetically soft materials after pyrolysis in argon already at 350°C. The main stages of ferrocene-containing oligoorganosiloxane thermal destruction in an inert atmosphere and the formation of a mixture of iron and silicon oxides during its thermal oxidative destruction are established by combination of TGA/DTA, IR spectroscopy and elemental analysis. The proposed approach opens up new possibilities for functionalizing silicates surfaces, creating magnetic glasses, as well as regulating surface energy and its components.