Copolymers ferrocene

PVP-Os Osmium-bipyridyl-modified quaternized poly 4-vinylpyridine) [102,206,207] PAH-Fc Ferrocene-modified polyallylamine [77, 101, 208] P(CM-FcJ Poly(vynil ferrocene) copolymer [224] PVn Polyalkylviologens (PVn, n number of methylene groups) [67, 104,... 

Ferrocene copolymers, (II) and (III), exhibiting redox potentials were prepared by Choi et al. (2) and used in organic memory devices. 

The copolymer of vinyl ferrocene (VF) and butadiene has also been reported in the literature for use as a binder for composite propellants. It does not require any burn-rate (BR) accelerator because of the presence of iron (Fe) in vinyl ferrocene which is converted to finely divided Fe203 (a well-known BR accelerator) during combustion. A few groups of scientists have also studied fluorocarbon polymers as binders for composite propellants because of their excellent compatibility with oxidizers and fuels coupled with high density. Accordingly, Kel-F elastomer (a copolymer of vinylidene fluoride and chlorotrifluoroethylene, trade name of 3M, USA) and Viton-A (copolymer of hexafluoropropylene and vinylidene fluoride, trade name of Du Pont, USA) have also been reported for this purpose. The structures of Kel-F 800 [Structure (4.13)] and Viton-A [Structure (4.14)] are ... 

M.G. Baldwin S.F. Reed, Vinyl Ferrocene-Butadiene Copolymers , USP 3753812 (1973)... 

CA, not found [Suggested is the use of the copolymers as binder for solid proplnt compns and as a means of increasing the burning rate of solid proplnts. For example, butadiene/vinyl ferrocene copolymer binder (10.0), isodecyl pelargonate plasticizer (10.0), Al powder (10.0) and AP (70 wt %) are mixed to form a proplnt... 

Ferrocene Butadiene Copolymer Burning Rate Catalyst , USP 3770287 (1973) CA 30,49970 (1974) 4) Ibid, Propellant Composition Con-... 

Vinylferrocene (22) may be polymerized (Section 57.3.2.2.i) to give a polymer in which the iron(II/III) redox centres are pendant from a carbon backbone. Copolymers have also been formed with styrene61 and acrylonitrile.62 Another approach using a different polymer is illustrated by the covalent binding of poly(methacryl chloride) to Sn02 electrodes followed by attachment of pendant ferrocene centres by reaction of hydroxymethylferrocene.63... 

The copolymers of type 67 exhibit the characteristic photochemical depolymerization noted for polysilanes, a source of their potential as photoresist materials. However, the presence of the ferrocenyl substituents results in a significant retardation of this depolymerization, presumably due to the ability of ferrocene to quench the triplet state responsible for the polysilane photochemistry164. Polymers of type 67 can be regarded as polysilanes with reversible redox behaviour. 

Poly(dithiafulvene)s toward intelligent functional materials have been synthesized [76-78]. An alternating -conjugated copolymer (13) of ferrocene with dithiafulvene showed a unique redox property [76]. Although 13... 

Perhaps the original hope for these polymers was that they would act simultaneously as immobilisation matrix and mediator, facilitating electron transfer between the enzyme and electrode and eliminating the need for either O2 or an additional redox mediator. This did not appear to be the case for polypyrrole, and in fact while a copolymer of pyrrole and a ferrocene modified pyrrole did achieve the mediation (43), the response suggested that far from enhancing the charge transport, the polypyrrole acted as an inert diffusion barrier. Since these early reports, other mediator doped polypyrroles have been reported (44t45) and curiosity about the actual role of polypyrrole or any other electrochemically deposited polymer, has lead to many studies more concerned with the kinetics of the enzyme linked reactions and the film transport properties, than with the achievement of a real biosensor. 

Siloxane Polymers. The synthesis of the ferrocene-modified siloxane polymers (A - E) has been described previously (25,27,32). Briefly, the methyl(2-ferrocenylethyl)-siloxane polymers were prepared by the hydrosilylation of vinylferrocene with the methylhydrosiloxane homopolymer or the methylhydrosiloxane-dimethylsiloxane copolymers (m n ratios of 1 1, 1 2, and 1 7.5 see Figure 1) in the presence of chloroplatinic acid as a catalyst. The methyl(9-ferrocenylnonyl)siloxane-dimethylsiloxane (1 2) copolymer was prepared via hydrosilylation of 9-ferrocenyl-l-nonene with the methylhydrosiloxane-dimethylsiloxane (1 2) copolymer. The molecular weight range of these ferrocene-modified siloxane polymers is approximately 5,000-10,000. Purification of the polymers was achieved by reprecipitation from chloroform solution, via dropwise... 

Figure 3. Synthetic procedure for the ferrocene-ethylene oxide-siloxane branch copolymers H and I.

Glucose Sensors. Siloxane polymers are known to be extremely flexible. This flexibility will, of course, be sensitive to the amount of side-chain substitution present along the polymer backbone. For instance, in the homopolymer used in these studies (polymer A), the presence of a ferrocenylethyl moiety bound to each silicon subunit should provide an additional degree of steric hindrance, and thus a barrier to rotation about the siloxane backbone, in comparison with the copolymers, which have ferrocene relays attached to only a fraction of the Si atoms. Because these siloxane polymers are insoluble in water, their flexibility is an important factor in their ability to facilitate electron transfer from the reduced enzyme. Relays contained within more rigid redox polymers, such as poly(vinylferrocene), cannot achieve close contact with the enzyme s redox centers and are thus less effective as electron transfer mediators (25,34). The importance of this feature can be seen quite clearly by comparing the mediating ability of the homopolymer A with that of copolymers B-D, as shown in Figures 4 and 5. 

The data of column 4 show the apparently paradoxical result that the mass of polymer alone (measured in air) is greater than that of the polymer plus liquid modulation layer. This is clear evidence that the oxidized PVF-co-PVP film is non-rigid in CH2C12. For this particular film, the dry mass of oxidised copolymer (including counter ion required by electroneutrality) corresponds to deposition of 29 nmol of ferrocene sites. The deposition process involved passage of 3.32 mC of charge, i.e. 34 nmol of ferrocene sites were oxidized in total. This implies an (average) deposition efficiency for this experiment of 85%. 

Although there are numerous references to the emulsion polymerization of vinyl ferrocene, they all appear to emanate from a single source (j4). These workers polymerized vinyl ferrocene alone, and with styrene, methyl methacrylate, and chloroprene. No characterization was reported other than elemental analysis. The molding temperatures reported (150 - 200 C) correspond to the Tg range indicated by Pittman ( ) for similar copolymers. The initiation system was preferably azobisisobutyronltrile, although potassium persulfate was also used. Organic peroxides were contraindicated, due to oxidation problems with the ferrocene moiety. 

The chiral vinylferrocene monomer 18 and the chiral copolymers 19a — e have been prepared for the first time. Insolubilization of the chiral ferrocene catalyst lowered the enantioselectivity to some extent compared with that of the soluble monomeric catalysts. Nevertheless, polymers 19a —e are usefull for the enantiose-lective synthesis of secondary alcohols. 

Scheme5-20. Copolymer from l,l -bis(2-mercapto-propylthio)ferrocene and divinyl sulfone [94],...

Polyesters 26 represent the first ferrocene-containing liquid crystal polymers [28]. These copolymers were found to be insoluble in THF, toluene, dichloromethane, chloroform, p-chlorophenol, and tetrachloroethane. The terephthaloyl chloride/iso-phthaloyl chloride ratio was maintained constant (7 3), but the content of the ferrocene unit was varied from 0 to 100%. 

Except for the structure containing 100% of ferrocene unit, which decomposed before melting, all the organometallic copolymers exhibited birefringent melts. Nematic textures were identified by means of polarized optical microscopy and, in one case, by X-ray diffraction studies. For comparison purposes, a polymer without ferrocene unit was prepared, but showed no mesomorphism. The authors deduced that the ferrocene framework was contributing to the liquid crystallinity of the ferrocene-containing polymers. 

The latest vinylferrocene monomer / -C5H4CH202CC(CH3) = CH2 rj -C5H4CH = C(CN)C02Et Fe 15 that undergoes radical polymerization has been prepared as shown in Scheme 10-3 [17] Copolymerization of the monomer with methyl methacrylate produced copolymer 16, via radical initiation using AIBN in benzene. The ethyl a-cyanoacrylate moiety on the ferrocene remained intact through the polymerization process. The thermal behavior of 16 was similar to that of polymethyl methacrylate glass transition temperature, 7 120 °C, melt transition... 

Methyl-( -ferrocenylethyl)- and methyl-[ -(r,3 -dimethylferrocenyl)ethyl]siloxane polymers 53 and 54, respectively were prepared by the hydrosilylation of vinyl-ferrocene and l,T-dimethylferrocene-3-vinylferrocene with methyl hydrosiloxane (molecular weight was originally reported to be 2270) or methylhydrosiloxane-dimethylsiloxane copolymer (molecular weight was originally reported to be 2000 — 2100) in the presence of chloroplatinic acid as a catalyst. The synthetic route is given in Seheme 10-25 [62], The reaction was monitored by IR spectroscopy until the complete disappearance of the Si-H absorption at 2161 cm". ... 

Many derivatives have been prepared from ferrocene monocarboxylic acid (S). Acetylferrocene was reduced by lithium aluminum hydride to the carbinol, and this was then converted into vinylferrocene. From this, polymers and copolymers with other polymerizable substances have been obtained. The polymers are easily obtainable in the cationic form and in the reduced, uncharged form, which are interconvertible (5). Urethanes (3), amino acids and urea, hydantoin and pyrazoline derivatives with ferrocenyl substituents have also been prepared (100, 178). 

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