Organoiron polymers

This reaction is a powerful tool and represents an alternative for the synthesis of substituted arenes difficult to prepare via classical electrophilic or nucleophilic aromatic substitution. Using bi- or polyfunctional arenes as starting materials, this reaction affords novel organoiron polymers [76] (Scheme 1.35). 

Cuadrado and co-workers prepared polysiloxanes with ferrocene and cobalticenium moieties in their backbone.180,181 Polymetallocene, 94, was synthesized by reacting l,3-bis(3-aminopropyl)-l,l,3,3-tetramethyldisiloxane with 1,1 -bis(chlorocarbonyl)ferrocene or 1,1 -bis(chlorocarbonyl)cobalticenium hexafluorophosphate. The organoiron polymer displayed a Mn = 10,600,180 whereas the organocobalt polymer possessed very low solubility in polar organic solvents.181 An alternative preparative route to this class of polymer is the reaction of l,l -bis((3-aminoethyl)ferrocene with dimethylbis(4-chlorocarbonylphenyl) silane.180... 

Aromatic and aliphatic spaces have been incorporated into organoiron polymers to determine their affect on the thermal stability and glass transition temperature of the polymers.256 The thermal stability of these polymers increased after the loss of the metallic moieties. The metallated polymer shows two decomposition steps at 245°C, corresponding to decomposition of the cyclopentadienyliron moieties and a second weight loss beginning at 511°C, corresponding to... 

The synthesis of cationic organoiron containing polymethacrylates and polystyrenes has been reported. The radical polymerization of methacrylate and styrene monomers containing cationic cyclopentadienyliron complexes produced polymers with cationic cyclopentadienyliron complexes in their side chains (Scheme 2.57).265,266 Monomer 216 and polymer 217 were both redox active and underwent reversible reduction processes. An organic analog of the cationic organoiron polymer was obtained by photolytic cleavage of the cationic cyclopentadienyliron... 

Abd-El-Aziz, A. S. Carraher, C. E. Jr. Pittman, C. U. Jr. Shears, J. E. Zeldin, M., Eds. Macromolecules Containing Metal and Metal-Like Elements, Volume 2 Organoiron Polymers-, Wiley Hoboken, N.J., 2004. 

Ahd-El-Aziz AS (2004) Overview of organoiron polymers. In Abd-El-Aziz AS, Car-raher CE, Pittman CU, Sheats JE, Zeldin M (eds) Macromolecules containing metal and metal-like elements, vol 2. Wiley, New York, p 1-27... 

Synthesis of Organoiron Polymers Containing Azo Dyes in Their Side Chains. 174... 

Synthesis of Organoiron Polymers with Azo Dyes in their Backbones. 182... 

Effects of Photoloysis on Organoiron Polymers Containing Azo Dyes. 185... 

Interest in organometallic maaomolecules has grown exponentially ever since Arimoto and Haven first polymerized vinylferrocene in 1955 [1]. Organometallic polymers are known to possess unique optical, magnetic, and thermal properties which allow for potential applications as chemical sensors, electrocatalysts, modified electrodes, and photo-active molecular devices [2-7]. Organoiron polymers are one of the most prevalent classes of organometallic polymers, with many reports on their synthesis and properties published over the past 50 years [8-11]. Of the many varieties of organoiron species, ferrocene and cationic cyclopentadienyliron complexes are most commonly incorporated into polymers. 

Polymerization of 5 gave organoiron polymers containing azo dyes in the side chains. The polymers (7, 8, 9) were prepared by nucleophilic aromatic substitution reactions between 5 and various O- and S- containing dinulceophiles (Scheme 7.3). 

Cuadrado and co-workers have prepared a pol5uner with Fe—Fe bonds in its structure (19) via reaction of a polysiloxane with Fe(CO)5 (44). The insoluble nature of this pol5uner indicated that cross-linking between polysiloxane chains occurred upon formation of the organoiron polymer. Silicon polymers containing Co—Co bonds (20) have been prepared via the reaction of Co2(CO)s with the triple bonds of a silicon based polymer (45). Mixed metal systems were also described in which complexes containing arenes coordinated to chromium tricarbonyl were reacted with Mo2Cp2(CO)e or Co2(CO)s. 

Volume 2 Organoiron Polymers Edited by Alaa S. Abd-EI-Aziz,... 

This chapter presents an overview of ad classes of macromolecules containing iron-carbon bonds and highlights some examples of these materials. The methods utilized to synthesize and characterize these polymers are described and the properties of some of the organoiron-based polymers are noted. This chapter focuses on the diversity formd in the area of organoiron polymer chemistry and briefly introduces the materials covered in the remaining chapters in this volume. 

The synthesis of polyaromatic ethers (37) and thioethers containing azobenzene dyes in their sidechains has been achieved. These polymers were prepared by reaction of cyclopentadienyliron-complexed azobenzene monomers with various dinucleophiles. These organoiron polymers were bright orange or red, and could be bleached by irradiating the polymer in a solution containing hydrogen peroxide. 

Nishihara has reported the complexation of poly(hexyl phenylene) with cyclopentadienyhron, where approximately 1 in every 1.6 aromatic rings was coordinated to the metalhc moiety. Spectroelectrochemical analysis of this organoiron polymer (40) suggested that a network was formed between the aromatic rings of neighboring polymer chains following reduction of the cationic iron centers to the neutral radicals. 

UV irradiation of pol3miers containing silole units in their backbones in the presence of iron pentacarbonyl resulted in the coordination of iron tricarbonyl units to one of every two silole rings in the polymer backbone. On doping, these organoiron polymers (48) become electrically conducting and their UV absorption bands are red shifted relative to the uncoordinated polymers. 

This chapter was intended to briefly introduce the types of organoiron polymers that have been developed since the early 1950s. Subsequent chapters in this volume will detail some of the advances that have taken place in recent years. The synthesis and properties of ferrocene-based polymers and polymers containing arene complexes of cyclopentadienyliron will be described. The properties and applications of some of these materials will be described, and the reader will hopefully gain an appreciation of organoiron polymers. 

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