Ferrocene Polymers Research Articles

Synthesis and Photophysical Properties of Ferrocene Containing Monomer and Polymer

Synthesis of a new monomer and polymer containing both ferrocene and hydrazone moieties are reported. The obtained materials were examined by various techniques including differential scanning calorimetry, UV, IR, NMR spectroscopy, and time of flight method. These materials may be of particular interest for the development of future electrophotographic photoreceptors as electron photoemission spectra of the layers showed ionization potentials of 5.35–5.41 eV. The hole drift mobility values in compositions of the designed structures with bisphenol Z polycarbonate exceeded 10−8 cm2/Vs at strong electric fields.

Inorganic and organometallic polymers

This report summarizes the many advances that were made in the area of inorganic polymer science in 2005. Key accomplishments in the synthesis of inorganic polymers include: macromolecules with metal–metal bonds, Pt-Au-containing polymers, highly metallized ferrocene polymers, conjugated phosphole- and silole-containing polymers, and novel metallo-supramolecular macromolecules. Several inorganic and organometallic polymers have been designed for sensor or electro-optical applications. In addition, a number of studies have focused on developing new classes of polyphosphazenes for biomedical applications.

Ferrocene polymers: current architectures, syntheses and utility

The discovery of ferrocene and its structural characterisation initiated an explosive rebirth of organometallic chemistry. Today, 50 years after this event, new uses are still being found for this remarkable organometallic moiety. The inclusion of ferrocene units into polymeric arrays has attracted much attention due to the electronic donating ability, reversible redox chemistry, steric properties and ready functionalisation of this stable fragment. This review outlines the current syntheses and architectures available for the construction of ferrocene-containing polymeric systems and examines some of the uses of the emergent metallocene polymers.

Rhodium‐ and ruthenium‐complex‐catalyzed condensation of ferrocene‐containing dithiols and diols with diarylsilanes to give silaferrocenophanes and ferrocene polymers

Rhodium‐ and ruthenium‐complex‐catalyzed condensation of ferrocene‐containing dithiols and diols with diarylsilanes to give silaferrocenophanes and ferrocene polymers

Rhodium‐ and ruthenium‐complex‐catalyzed condensation of ferrocene‐containing dithiols and diols with diarylsilanes to give silaferrocenophanes and ferrocene polymers

Abstract1,1′‐Ferrocenedithiol reacts with di(4‐methoxyphenyl)silane, diphenylsilane, and di(4‐fluorophenyl)silane in the presence of RhCl(PPh3)3 catalyst to give mixtures of 2,2‐diaryl‐1,3‐dithia‐2‐sila[3]ferrocenophanes (1a–3a) and (FcSSiAr2S) n (Fc = 1,1′‐ferrocenylene; 1b: Ar = C6H4OMe‐4; 2b: Ar = Ph; 3b: Ar = C6H4F‐4). The products are isolated and characterized by NMR spectroscopy and elemental analyses. The polymers 1b–3b, obtained from a toluene‐soluble fraction of the products, show GPC elution patterns corresponding to Mn values of 2700–4600 (polystyrene standards). The UV–vis spectra of the ferrocenophanes and polymers exhibit a d–d transition peak at about 440 nm, while the polymers show a π–π* transition peak at 320–330 nm. The cyclic voltammograms of 3a (Ar = C6H4F − 4) and 3b show a reversible redox of the iron center at 0.27 V and 0.35 V (Ag+/Ag) respectively. Reaction of 1,1′‐ferrocenedimethanol with diphenylsilane in the presence of RuCl2(PPh3)3 catalyst results in selective formation of 3,3‐diphenyl‐2,4‐dioxa‐3‐sila[5]ferrocenophane (4), whose structure was determined by X‐ray crystallography. Copyright © 2001 John Wiley & Sons, Ltd.

Erratum: A Preliminary Study of the Toxicological Properties of Selected Polymer-Ferrocene Conjugates

Prompted by early observations of the cytotoxic and antineoplastic properties of certain ferrocene and ferricenium derivatives, efforts in this laboratory were focused on the synthesis of carrier-bound ferrocene compounds. Subsequent cell culture tests carried out with selected conjugates obtained in that program showed these polymers to be highly active antiproliferative agents. In the present project toxicological work has been performed in vivo on several ferrocene conjugates in an effort to assess their toxic effects in experimental animals (CD-1 mice). The conjugates, all based on an α,β-DL-polyaspartamide backbone structure, comprise the ferrocene drug model as a terminal on short side chains containing biofissionable amide or ester links for intracellular drug release. The polymers, dissolved in phosphate-buffered saline, have been injected in predetermined concentrations into the vein of the mice, and the maximum tolerated dose (MTD) levels have been determined, the latter referring to the highest dose levels administered that would allow long-term survival of the test animals. For the five conjugates tested, MTD levels range from about 3 to 30 mg Fe/kg or 0.05–0.66 mmol Fe/kg. Compared on a molar metal-to-metal basis with similarly structured platinum conjugates tested previously (MTD, ∼0.14–2.66 mmol Pt/kg), these values are indicative of comparatively high toxicity of the ferrocene polymers. Some implications of these findings are discussed.

Electron transfer of conjugated polymeric ferrocenes

This paper describes three topics on the π-conjugated ferrocene oligomers and polymers; the first is the dependence of intervalence-transfer bands for mixed-valence oligo(1,1'-dihexylferrocenylene)s on the oxidation number and the number of ferrocene units, the second is synthesis of azo-bridged ferrocene oligomers and a polymer and electrochemical and optical analysis of internuclear electronic interactions in their mixed-valence states and the third is synthesis, redox behaviors and electrodeposition of oligoferrocenylene-modified gold clusters.

Synthesis of Soluble 1,3-Bridged Ferrocene-Acetylene Polymers and the Divergent-Convergent Synthesis of Defined Oligomers

A –CH2NMe2 group attached to ferrocene can be used as an ortho/ortho-directing group to selectively synthesize 1,2,3-substituted ferrocenes, which are used as starting materials for novel 1,3-linked ferrocene polymers and oligomers. The Sonogashira coupling reaction of 1-(I),2-(CH2NMe2)-ferrocene with HC≡CSiEt3 results in 1-(C≡CSiEt3),2-(CH2NMe2)-ferrocene (1b), which – following an ortho-lithiation/iodination sequence – is converted into 1-(I),2-(CH2NMe2),3-(C≡CSiEt3)-ferrocene (1d). Removal of the –SiEt3 protective group yields 1-(I),2-(CH2NMe2),3-(C≡CH)-ferrocene, which can be polymerized under Sonogashira conditions to yield a soluble, bimodal ferrocene-acetylene polymer of MW = 3700/7100 and Mn = 4272. To understand the properties of the polymer better and to evaluate the effect of 1,3-substitution on the electronic communication between the metal centers, a divergent-convergent approach was used to synthesize defined di-, tri- and tetranuclear ferrocenes. Accordingly, 1d was cross-coupled with 1-(CH2NMe2),2-(C≡CH)-ferrocene to give [2-(CH2NMe2)-ferrocene-1-yl]-C≡C-[2-(CH2NMe2),3-(C≡CSiEt3)-ferrocene-1-yl] (2a). Removal of the protective group in 2a led to [2-(CH2NMe2)-ferrocene-1-yl]-C≡C-[2-(CH2NMe2),3-(C≡CH)-ferrocene-1-yl] (2b), which was treated with [1-(I),2-(CH2NMe2)ferrocene-3-yl]-C≡C-[2-(CH2NMe2),3-(C≡CSiEt3)-ferrocene-1-yl] (2c) to result in the corresponding tetrameric ferrocene (4a).

Ferrocene‐containing polymers as electron transfer mediators in carbon paste electrodes modified with PQQ‐dependent aldose dehydrogenase

AbstractThe aim of this work was to improve an aldose‐detecting biosensor based on quinoprotein aldose dehydrogenase (ALDH). Polymer‐bound ferrocene derivatives with four different structures were studied as electron transfer mediators between the coenzyme of ALDH, pyrroloquinoline qninone (PQQ), and the conducting electrode material. The ferrocene polymers were mixed into carbon paste, which was used for the preparation of aldose‐detecting electrodes by immobilizing ALDH on the carbon paste surface by adsorption. The current responses of the ferrocene polymer modified electrodes were studied and the effect of the polymer structure on the response was examined. The electrodes modified with all four polymers showed maximum response at the working potential around 300 mV (vs. Ag/AgCl). The operational stability of the ferrocene polymer modified electrodes was better than that of corresponding dimethylferrocene modified electrodes. The ferrocene polymer modified electrodes seemed to be suitable for the measurement of real samples.

The Synthesis and Properties of Face-to-Face Metallocene Polymers

Polymerization of 1,1'-bis(8-cyclopentadienyl-1-naphthyl)ferrocene (8) and its alkylated analogs 13a-d, through base-assisted, metal complexation, gives a new class of metallocene polymer 14 in which contiguous metallocene rings are held in a stacked, face-to-face orientation. The monomers are prepared in three steps from 1,8-diiodonaphthalene (2) through coupling with cyclopentadienylcopper reagents to give 1-cyclopentadienyl-8-iodonaphthalenes 4 or 11, conversion to the ferrocene derivative by metal complexation with ferrous chloride, and then cyclopentadienylation. Polymers incorporating only ferrocene units as well as copolymers of ferrocene and nickelocene or cobaltocene, in which the metallocenes alternate within the chain, have been prepared. These have been characterized by GPC analysis and by their infrared and 1 H NMR spectra. Polymerization of 1,8-bis(cyclopentadienyl)-naphthalene (15) and its alkylated derivative 17 by base-assisted complexation provides a new pathway to a broader range of metallocene polymers. These monomers have been polymerized through base-assisted metal complexation with nickel(II) salts to gives low molecular weight, stacked nickelocene polymers. Electrical conductivity of compressed pellets of the ferrocene polymer 14b, which is less than 10 -12 S cm -1 for the unoxidized material, is greatly increased on oxidative doping with iodine, and reaches a maximum of 6.7 x 10 -3 at a nominal oxidation level of 37%. The conductivity data are best accounted for in terms of a phonon-assisted electron-hopping mechanism between Fe(II) and Fe(III) centers. The behavior of the doped ferrocene polymer as a weakly interacting mixed-valence system is supported by Mossbauer spectra of oxidized polymer, which show trapped valence states over a broad temperature range and slow paramagnetic relaxation for the Fe(III) sites at lower temperatures. Bulk susceptibility measurement of paramagnetic polymers shows room temperature magnetic moments for the iron-cobalt copolymer 14i of 5.2 μ B and for the nickel polymer 18 of 5.3 μ B . These values are significantly larger than the moments of either cobaltocene or nickelocene.

Polyferrocenes as mediators in amperometric biosensors for glucose

This paper describes the first successful application of polymeric ferrocenes as mediators in amperometric biosensors. The results have implications for the design of stable biosensors and bioelectric devices involving electron transfer from oxidoreductases to electrode surfaces. The behaviour of two ferrocene polymers in enzyme electrodes was explored and a distinctive pH profile was noted. It is suggested that changes in either the enzyme conformation or the polymer in response to hydrogen ion concentration mat explain the difference in behaviour between monomeric and polymeric ferrocenes.

The magnetic properties of ferrocene based macromolecules

Magnetic susceptibility data for conjugatively linked biferrocenes and a methylene bridged ferrocene polymer are presented. In 9,10-di((2-ferrocenyl)vinyl)anthracene a rigid divinylanthracene bridge is connecting two ferrocene units, and the oxidation of both iron centers leads to an antiferromagnetic coupling. In contrast, ferromagnetic coupling between iron centers is indicated for 2,2'-cis,trans-di((2-ferrocenyl)vinyl)biphenyl, where a twist around the phenyl-phenyl bond in the divinylbiphenyl bridging molecule is likely to occur.

Electrochemical characterisation of polyvinylferrocene polymers: substituent effects on the redox reaction

The electrochemical behaviour of substituted ferrocene monomers and polymers was investigated using the techniques of cyclic voltammetry and pulse voltammetry at a platinum electrode. Both monomers and polymers obeyed the Hammett linear free-energy relationship between the half-wave potentials, E1/2, and the σ constants of the substituents. Normal pulse-voltammetric studies indicate that nearly all the ferrocene residues in the polymer are accessible to electron transfer in the electrode reaction. Diffusion coefficients calculated for substituted ferrocene polymers were in good agreement with those calculated using theoretical treatments.

Crystal and molecular structure of a segment of a stacked face-to-face ferrocene polymer

The crystal and molecular structure of a fragment of a face-to-face metallocene polymer, the [2,3]-oligomer( 2a, n = 2) of 1,8-diferrocenylnaphthalene( 1a), has been determined in order to better define the structural features of the polymer. The molecular structure of this compound shows the same form and magnitude of molecular distortions as those found in the monomeric unit 1a. An unusual feature of the oligomer is the cis arrangement of the two naphthalene nuclei, which brings several of the carbon centers on each naphthalene ring in close proximity. These structural aspects are discussed in the context of possible structures for the related polymer.

Ferrocene-Nafion Modified Electrode And Its Catalysis For Cerium (IV)

Abstract Ferrocene-Nafion modified electrode is prepared, it exhibits an interesting electrocatalysis for Ce(IV) reaction. Many investigations have been done on ferrocene (Fc) derivative and polymer modified electrodes,1–6 but seldom reported the modified electrodes simply with Fc containing no substituents. Because in the latter case it was very difficult to attach the modifier to the electrode surface by conventional methods such as plasma polymerization,1 electrodeposit,2 electropolymerization,3 covalence link,4 ion exchange5 and polymer coating6 etc. Nafion modified electrodes7–10 have attracted much interest for its ion exchange property. Considering Nafion possesses another property-hydrophobic interaction, here we propose a noval modified electrode with complex Fc by the help of Nafion. The Fc-Nafion modified electrode prepared shows well defined cyclic voltammogram of Fc. It has more stable and reversible voltammetric characteristics compared with other Fc derivative electrodes. What interesting c...

Ferrocene polymers with "polyaniline" backbones

Ferrocene polymers with "polyaniline" backbones

Ferrocene polymers as polymerization initiators—IV. Polymerization of some p-substituted chloroformylated vinylic monomers

The redox catalytic activity of a polymer obtained by the thermal polymerization of 1-(α-chloro-β-formyl)-1′-acetyl-ferrocene was tested in the polymerizations of some p-substituted chloroformylated vinylie monomers viz. α-chloro-β-formyl- p-methoxy-styrene and α-chloro-β-formyl- p-iodostyrene. The products are oligomers with average polymerization degree between 5–12. The reactivities of the monomers were estimated by the MO Hückel method.

Thermal stability of some polyferrocenyleniminoimides and polyferrocenylenazomethines

The thermal stability of new ferrocene polymers from the class of polyferrocenyleniminoimides and polyferrocenylenazomethines was studied by means of differential thermal analysis as well as thermogravimetry.It was established that polyferrocenylenazomethines show good thermal stability up to 200° and are more stable than polyferrocenyleniminoimides.The presence of ethereal, sulphidic and disulphidic bridges in the diaminic component of the polymers decreases their thermal stability.

New ferrocene polymers: polyferrocenyleniminoimides

The influence of the reaction conditions in the polycondensation of 1,1′-diacetylferrocene and 1,1′-bis[β-(2-furyl)acryloyl]ferrocene with biuret is studied and the optimum parameters for obtaining new ferrocene polymers, polyferrocenyleniminoimides, determined. The synthesized polymers are stable up to 225°C and show semiconducting properties.

Chemically modified electrodes: Part XIV. Attachment of reagents to oxide-free glassy carbon surfaces. Electroactive RF polymer films on carbon and platinum electrodes

Abstract : Reactive, deoxygenated glassy carbon surfaces prepared by mechanical abrasion under nitrogen or argon plasma etching react with selected molecules to yield surfaces with immobilized molecular surface states. Vinyl ferrocene and a ruthenium pyridine complex are immobilized on glassy carbon in this way. Introduction of vinyl ferrocene directly into an RF plasma discharge leads to electroactive ferrocene polymer deposition on glassy carbon and Pt surfaces. Surface waves corresponding to 3 x ten to the minus 8th power moles/sq cm ferrocene are obtained in this way. (Author)