SILOXANE AND ORGANOSILICON DIMERS, MONOMERS, AND POLYMERS WITH AMIDE-LINKED FERROCENYL MOIETIES - SYNTHESIS, CHARACTERIZATION, AND REDOX PROPERTIES

Polymers [-Si(CH3)(2)(CH2)(3)NHC(O)(eta(5)-C5H4)Fe(eta(5)-C5H4)C(O)NH(CH2)(3)Si(CH3)(2)O-](n) (4), and [C6H4C(O)NHCH2CH2(eta(5)-C5H4)Fe(eta(5)-C5H4)CH2CH2NHC(O)C6H4Si(CH3)(2)-](n) (5), in which the amide-linked ferrocenyl moieties are part of the main polymer chain, have been prepared via solution and interfacial polycondensations. As an aid to the spectroscopic and electrochemical characterization, the corresponding dimeric model compounds [{eta(5)-C5H5}Fe{eta(5)-C5H4C(O)NH(CH2)(3)Si(CH3)(2)}](2)-O (1), and [{eta(5)-C5H4CH2CH2NHC(O)(C6H4)}](2)SiMe(2) (2) were synthesized. Electrochemical measurements show that in 1 and 2 oxidation wave represents a two-electron process, as expected for independent reversible one-electron transfer, at the same potential, of the two ferrocenyl moieties. The cationic dimetallic species [1(2+)][PF6-]2 and [2(2+)][PF6-]2 have been generated and characterized via infrared spectroelectrochemistry. A redox-active monomer, {eta(5)-C5H5}Fe{eta(5)-C5H4C(O)NH(CH2)(3)SiCH3(OCH2CH3)(2)} (3), has been successfully attached to Pt electrodes and to silica surfaces, via siloxane bond formation. In addition, a series of poly(methylsiloxanes) 6-11, containing pendant ferrocenyl moieties attached to the polymer backbone through amide linkages, with varying degrees of ferrocene substitution, were prepared and characterized. Solution electrochemical studies showed that all the ferrocenyl redox centers present in the polymers are electrochemically independent, and that neutral 6, 7, and 10 undergo oxidative precipitation, yielding polymer films on the platinum electrode surfaces. The electrochemistry of electrodes modified with electroactive films of ferrocene-containing polysiloxanes was studied by cyclic voltammetry. Amperometric glucose sensing electrodes based on a ferrocene-containing poly(methylsiloxane) have been prepared.