Anionic ring-opening oligomerization and polymerization of silicon-bridged [1]ferrocenophanes: Characterization of short-chain models for poly(ferrocenylsilane) high polymers

Abstract

Polymers with skeletal transition-metal atoms are attractive materials as a result of their novel electrical, optical, magnetic, and chemical characteristics.1•2 We have previously reported the preparation of the first examples of high molecular weight poly-(ferrocenylsilanes) 1 via the thermal ring-opening polymerization (ROP) of strained, ring-tilted, silicon-bridged [ 1 ] ferrocenophanes such as 2 at elevated temperatures.3 4567These polymers display novel electrochemical properties which are indicative that the iron atoms interact with one another, and several show evidence for the formation of ordered structures in the solid state.4-7 Studies of well-defined short-chain oligomers would be expected to provide additional understanding of the characteristics of these unusual polymers, but such species are often very difficult to prepare and crystallize for X-ray diffraction studies.

A linear oligo(ferrocenylsilane)

“…This geometry can be described by the angle between the least-squares planes containing C1-C5 and Cll-C15, which is 84.32(16)". The conformation of the title compound is similar to that of the five-ferrocene unit oligomer which was recently characterized by X-ray crystallography (Rulkens, Lough & Manners, 1994).…”

“…We recently reported the synthesis of a range of oligo(ferrocenylsilanes) (Rulkens, Lough & Manners, 1994) (see scheme above). The title compound was separated from the mixture of oligomeric products by column chromatography.…”

The synthesis and polymerization behaviour of silicon-bridged [1]- and [2]ferrocenophanes with sterically demanding trimethylsilyl substituents attached to the cyclopentadienyl rings

“…In 1992, we reported the synthesis of soluble, high molecular weight poly(ferrocenylsilanes) (2) via the thermal ringopening polymerization (ROP) of silicon-bridged [llferrocenophanes (1) (5). More recently, we have demonstrated that living ROP can also be achieved in solution at room temperature in the presence of anionic initiators (6). This has provided access to poly(ferrocenylsi1anes) with controlled molecular weights as well as to block copolymers (7).…”

Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization

“…For example, well-defined BCs consisting of polyisoprene and polymers with laterally bonded alkyl-silane groups were recently prepared by sequential anionic polymerization and have been used as membranes for gas separation applications [22]. The anionic ring opening polymerization (ROP) of ring-strained cyclic silanes, carbosilanes and metal-containing carbosilanes has also been reported and lead to well-defined polymers [23][24][25][26][27][28][29][30][31][32]. Out of all cyclic carbosilanes, 1,1-dimethylsilacyclobutane (DMSB) is a well-known monomer, due to its convenient chemical and also commercial availability.…”