Organometallic Gels: Characterization and Electrochemical Studies of Swellable, Thermally Crosslinked Poly(ferrocenylsilane)s

Investigations on a series of crosslinked poly(ferrocenylsilane) networks that have been prepared via the ring-opening copolymerization of the silicon-bridged [1]ferrocenophane fcSiMe2 (fc = Fe(η-C5H4)2) with controlled amounts of a spirocyclic [1]ferrocenophane fcSi(CH2)3 are reported. These crosslinked poly(ferrocenylsilane)s have improved thermal stability relative to their linear counterparts. The swelling response was investigated as a function of temperature, solvent and crosslink density. As expected, the degree of crosslinking had a dramatic effect on the swelling in various media. From swelling measurements in a variety of liquids, it was determined that the best solvents for poly(ferrocenyldimethylsilane) are THF, chloroform, and dichloromethane. The solubility parameter (δ) for the linear homopolymer was found to be 18.7(7) MPa1/2. Reversible electrochemical oxidation of the gel was observed at oxidation potentials greater than 450 mV (vs Ag/AgCl), consistent with the oxidation potential of the linear homopolymer, and an intervalence charge transfer band was detected at 1300 nm for the partially oxidized material.