Ferrocene-functionalized polymer synthesis

Ferrocene-Functionalized Polymer Brushes Synthesis and Applications 67... 

Synthesis of Ferrocene-Functionalized Polymer Brushes by ATRP... 

Synthesis of ferrocene-functionalized polymer brushes on a gold substrate by simultaneous SI-ATRP and click chemistry. (Reprinted with permission from Xu et al. 2010. One-Pot Preparation of "Ferrocene-Functionalized Polymer Brushes on Gold Substrates by Combined Surface-Initiated Atom Transfer Radical Polymerization and "Click Chemistry." Langmuir 26 (19) 15376-15382, copyright (2010) American Chemical Society.)... 

Pittman and coworkers reported a number of ferrocene-functionalized polymers in the 1960s and 1970s that not only included the synthesis but also the properties of these polymers. " In particular, the bulk and solution polymerization of vinylferrocene along with the physical, chemical, and electrical properties of many polymers and copolymers were studied. The copolymerization of vinyl-ferrocene with styrene was reported by Frey and co-workers in 1999, using living radical initiator 2,2,6,6-tetramethyl-l-pyperidinyl-l-oxy (TEMPO). The polymers obtained by this method were block copolymers with narrow polydis-persities. 

In the synthesis of ferrocene-functionalized polypyrrole systems, numerous derivatives are readily obtained by substitution at either the 3-position of the ring or on the nitrogen of the pyrrole prior to polymerization. It was reported that polymers with both metallic properties and enhanced solubility may be synthesized by judicious derivatization and choice of polymerization conditions, such as a variety of processing solvents [67, 68]. 

The synthesis of conjugated polymers containing ferrocene units in their backbones has received much attention in recent years (78-81). Bochmann and co-workers have described the synthesis of ferrocene-based polymers via palladium-catalyzed coupling reactions of dihalide or divinyl functionalized ferrocene monomers with aromatic spacers (37) (78). 

The synthesis and properties of star polymers and dendrimers functionalized with ferrocene units has attracted a great deal of attention. The synthesis of high-generation dendrimers functionalized with chiral ferrocenyl units in their structures has been reported. The chiroptical properties of this class of dendrimer was dependent on the number of ferrocenyl groups and their chemical environment, but not on their position within the dendrimer. Deschenaux has reported the synthesis of hquid crystalline ferrocene-based polymers prossessing an enantiotropic smectic A phase. Ferrocene-functionahzed cyclic siloxane (29) and silsesquioxane branched polymers have also been reported. A hyperbranched polymer with a cubic silsesquioxane core was used to mediate the electrocatalytic oxidation of ascorbic acid. 

The polycondensation of acetylene-substituted metallocenes has yielded polymers containing backbone aUcyne bridges. The synthesis of l-iodo-2-methoxy-methyl-3-ethynylferreocene and l-iodo-2-(N,N-dimethylamino methyl)-3-ethynyl-ferreocene was reported by Plenio and coworkers. Polymerization of these ferrocene-based complexes gave rise to soluble bimodal 1,3-linked ferrocene-acetylene polymers. Polymers exhibiting optical activity or functionalized sidechains were produced via Sonogashira coupling reactions. 

Polymerization of organoiron monomers has also resulted in the production of liquid crystalline polymers containing ferrocene units in their sidechains. " Scheme 6 illustrates Deschenaux s free-radical synthesis of ferrocene functionalized thermotropic liquid crystalline polymethacrylates Monomer 31 and its corresponding polymer 32 exhibited enantiotropic smectic A and C phases. 

Ferrocene is an attractive and convenient organometallic species to incorporate into conjugated polymers—it is stable, easy to functionalize, has reversible electrochemistry, and its derivatives (both monomeric and polymeric) can be easily characterized [e.g., by nuclear magnetic resonance (NMR) spectroscopy]. Ferrocene has been incorporated into the backbone and side chains of polythiophene 45 In 1999, both Higgins and Wolf independently reported the synthesis of polythiophenes with ferrocene in the backbone.46,47 Electropolymerization of ferrocene substituted... 

In the 1980s, the successful synthesis of elastomeric polyamides 120 of high molecular weight (d/n =10,000-18,000) was reported from the polycondensation of l,l -bis(/ -aminoethyl)ferrocene with diacid chlorides (Scheme 13). Also, polyureas 121 were prepared from the same ferrocene monomer and diisocyanates, and polyesters and polyurethanes were prepared from l,l -bis(/ -hydroxyethyl)ferrocene. However, the latter materials had much lower molecular weights and were characterized only by scanning electron microscopy. X-ray, and IR analyses. The introduction of ferrocenes in which the functional groups are separated from the cyclopentadienyl ring by at least two methylene units was crucial in order to reduce steric effects and to avoid the instability found previously in polymers of a-functionalized ferrocene due to the a-ferrocenyl carbonium ion stability. 

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