Polycondensation reactions ferrocene polymers

The red-orange polymer 4.18 and analogous materials were also prepared by Pd-catalyzed polycondensation reactions, and analysis by cyclic voltammetry showed the presence of weak metal-metal coupling Ey2=0.07-0.12 V) between the widely spaced iron centers [49]. Low molecular weight ferrocene polymers 4.19 with fluorinated arene ligand spacers have also been prepared and, intrigu-ingly, show no detectable metal-metal communication [52, 53]. Low molecular... 

More recently, a soluble polymer (32) was prepared via reaction of l,l -ferrocenedimethanol with 4,4 -biphenyltetraamine in the presence of [RuCl2(P(C6115)3)3] (70). Approximately 20% of the iron centers were foimd to be in the Fe(III) state as a result of oxidation by ruthenium complexes formed during the polycondensation reaction. Wright and co-workers have reported the synthesis of ferrocene-based polymers possessing nonlinear optical properties (33) (71-73). These polymers were formed by polycondensation of a difunctionabzed ferrocene monomer (71). 

Ferrocene polymers with nonlinear optical properties were also prepared via Knoevenagel polycondensation reactions. " Scheme 32 shows the reaction of monomer 123 with 124 to give the accordion polymer 125 with values ranging from 9100 to 26,600." A mixture of A and Z isomers was initially obtained however, an isomerically enriched polymer (98% E isomer) could be isolated through selective precipitation. 

Polycondensates 27 and 28 (Fig. 9-22), incorporating either the 1,3- or 1,1 -disubstituted ferrocene unit, were prepared by solution polymerisation. Polymers 27 [25] were obtained by reaction of the novel monomer 29 [25] (Fig. 9-23) with the desired bis(acid chloride) 31 (Fig. 9-23) in refluxing CH2CI2 in the presence of triethylamine. Polymers 28 [25] were prepared following the same procedure from bis-phenol 30 [16] (Fig. 9-23). 

J/n < 6,000). Often, no analytical data or structural characterization was provided. Room-temperature interfacial polycondensation methods were also investigated as a convenient alternative to classical polycondensations. Such methods were first reported for the preparation of polyamides and polyesters from the reaction of l,l -ferrocenyldi-carbonyl chloride with several diamines and diols. The synthesis of polyurethanes using this technique was also reported and involved the condensation of l,T-ferrocenedimethanol and l,T-bis(dihydroxyethyl)ferrocene with diisocyanates. Once again, however, these polymers possessed low molecular weights.The early research in these areas has been summarized and critically reviewed and will not be discussed further here. ... 

A typical early route to polyferrocenylenes (40) with M < 5000 involved polycondensation processes such as the recombination of ferrocene radicals generated via the thermolysis of ferrocene in the presence of peroxides. However, these materials have been foimd to possess other fragments such as CH2 and O in the main chain (128,129). More structurally well-defined polyferrocenylenes (40) (Mn < 4000) have been prepared (130) via the condensation reaction of 1,1-dilithioferrocene TMEDA (tetramethylethylenediamine) with 1,1-diiodoferrocene and, significantly, the reaction of l,l -dihaloferrocenes with magnesium (eq. 30) has been shown to afford low molecular weight (M = 4600 for soluble fractions) materials with appreciable crystallinity (131). In the latter case, oxidation with 7,7,8,8-tetracyanoquinodimethane (TCNQ) afforded doped polymers that were delocalized on the Mossbauer time scale (ca 10 s) at room temperature and which possessed electrical conductivities of up to 10 S/cm. 

Reductive polycondensation of 1,1 -diacetyl ferrocene with low-valent titanium, synthesized by a reaction of TiCU with Zn powder [32, 33], yield polymers with ferrocene-vinylene repeating units [34] ... 

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. 

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