Ferrocenophanes polymerization

Figure 25 The ring-opening polymerization of strained boron-bridged [ 1J ferrocenophanes (35a-c) to produce poly(ferrocenylboranes) (36a-c). (Adapted from ref. 57.)...

Germanium-bridged [l]ferrocenophanes undergo a number of ring-opening polymerization reactions to yield ferrocene-containing polymers, and the versatility of this interconversion has been reviewed. A -GeMe2-... 

The silicon-bridged [l]ferrocenophane LXXXV undergoes polymerization at 120-150°C to yield polymers of number-average molecular weights up to 105 with PDI 1.5-2.5... 

Cross-linked electroactive gels have been produced by the addition of a spirocyclic ferrocenophane, 6.32, into the polymerization of 6.19 (R/R = Me/Me).25 These cross-... 

Attempts have been made to polymerize other monomers related to ferrocenophanes. Diaz, Panned, and coworkers35 found that the presence of two silicon atoms in the ring (6.33) inhibited polymerization. However, the analogous carbon ferrocenophane (6.34) was shown by Nelson, Rengel, and Manners to polymerize at 300 °C. 

Both PFS-PI and PFS-PDMS are synthesized by two-step anionic polymerization. The synthetic approach for the preparation of PFS-PDMS is shown in Scheme 1 [8,9] n-butyllithium was used to initiate the polymerization of the strained silicon-bridged ferrocenophane in THF solution, while the second block was built by the subsequent addition of hexamethyltrisiloxane (D3). The reaction was terminated with chlorotrimethylsilane. To obtain PFS-PI, the PI block was initiated with butyllithium, followed by the addition of the silicon-bridged ferrocenophane. 

RING-OPENING POLYMERIZATION OF SILICON-BRIDGED [1]FERROCENOPHANES... 

B. Synthesis, Properties, and Ring-Opening Polymerization of Silicon-Bridged 1 ]Ferrocenophanes... 

Prior to 1992 no efforts to prepare polymers with main chains consisting of ferrocene and organosilane units via ring-opening methods had been reported. The first developments in this area involved attempts to polymerize silicon-bridged ferrocenophanes and related species (23,41). The first successful ROPs involved the use of [l]silaferrocenophanes as cyclic monomers, and the progress in this area to date together with relevant previous work is now reviewed. 

A. Ring-Opening Polymerization of Hydrocarbon-Bridged [2 Ferrocenophanes... 

Gates DP (1997) The synthesis, structure, reactivity and polymerization behavior of boron- and sulfur-nitrogen-phosphorus heterocycles and highly strained chalcogen- and boron-bridged [1], ferrocenophanes. PhD thesis, University of Toronto... 

Homo- and block copolymers from phosphorus-bridged [l]ferrocenophanes were isolated from living anionic ring opening polymerizations.113 Scheme 2.15 shows preparation of borane adducts of poly(ferrocenylphosphine)s by thermal ROP or addition of BX3 (X = H, Cl).114... 

Scheme 2.16 displays the thermal ROP of a number of phosphorous-bridged ferrocenophanes, resulting in the isolation of phosphorus(III)- and (V)-containing polymers 59a-c.115 Reaction of poly(ferrocenylphosphines) 59a-c with elemental sulfur generated poly(ferrocenylphosphine sulfides) 60a-c. Polymers 60a-c could not be directly prepared from thermal ROP of phosphine sulfide-bridged ferrocenophanes due to partial decomposition of the products. However, ferro-cenophane 58a polymerized via anionic ROP and reacted with sulfur.116 The resultant polymers had Mn = 3600-32,000 for monomer-catalyst ratios that were varied from 11 1 to 100 1. 

Scheme 3.5 Sequential anionic polymerization of styrene and dimethylsila[l]ferrocenophane.

Scheme 3.6 Sequential anionic polymerization of dimethylsila[l]ferrocenophane and hexamethyl-cyclotrisiloxane.

Scheme 3.12 Photolytic anionic ring opening polymerization of dimethylsila[l]ferrocenophane (From Tanabe and Manners.33 Reproduced with permission.)...

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