Mechanochemical synthesis of polyferrophenylsiloxanes

The interaction of iron tris(acetylacetonate) with polyphenylsiloxane (PPS) under conditions of mechanochemical activation followed by boiling in toluene with a PPS/Fe(CH₃COCH₂COCH₃)₃ ratio of 3:1, 2:1, 1:1. The polymers were isolated by reprecipitation from a toluene solution with hexane. The composition and properties of polyferrophenylsiloxane (PFPS) were studied using elemental analysis, gel chromatography, X-ray phase analysis, positron annihilation spectroscopy, Mössbauer, and IR spectroscopy. It is shown that the molecular weight of the obtained polymers is 6500–7000 u. The fragmentary structure of oligoferrophenylsiloxane with a Si/Fe–3/1 ratio was studied using acid cleavage with ferrocyanade acid. Oligophenylsiloxanes soluble in toluene with different molecular weights (4500 g/mol, 1700–1600 g/mol, 600 g/mol) were isolated. In this case, the bulk corresponded to the oligomer 4300–4500 g/mol, in order to obtain a Si/Fe ratio of three, a block structure was proposed, consisting of siloxane and chelate blocks. Thus, the process of splitting the siloxane bond is accompanied by the reaction of copolymerization of polyphenylsiloxane and chelate cycles of iron acetylacetonate. The data of Mössbauer spectroscopy indicate the presence of oxygen atoms associated with silicon and iron, oxygen atoms of the acetylacetonate ligand in the environment of the iron atom.