Mixed-Valence Behavior in an Iodine Complex of a Ferrocenylenesilylene Polymer

Abstract

Structural and thermal characteristics of an amorphous iodine complex of a ferrocenylenesilylene polymer, [-(C 5 H 4 )Fe(C 5 H 4 )Si(CH 3 )(C 6 H 5 )‚(I 1.5 )-] n , have been measured using 57 Fe Mo ¨ssbauer, IR and Raman spectroscopy, X-ray diffraction, and thermomechanical analysis. The iodine-doped macromolecules are mixed-valence salts with a localized electron structure on the 57 Fe Mo ¨ssbauer time scale, in which ferrocenylene units and ferrocenium moieties coexist. These macromolecules consist of blocks containing ferrocenium moieties and sequences of nonoxidized ferrocenylene units. The environment about the ferrocenium moieties consists of both single I 3and polyiodide [I 3 ] -‚nI 2 species. Mo ¨ssbauer data, collected in the range 5-300 K, are interpreted in terms of the temperature dependence of the Lamb-Mo ¨ssbauer factor and reversible electron transfer with an activation energy of 4.7 kJ/mol. The transformations of [I 3 ] -+ I 2 clusters to I 3are proposed to accompany Fe(II)-Fe(III) oxidation.

Molecular iodine/polymer complexes

“…The concentration of I 5¯ ion increased with greater levels of doping, which was in tune with the observed red shift of the UV absorption and the increasing con ductivity of the thin films. I 2 poly(ferrocenylenesilylene) with R 2 = MePh was found to contain 1.5 iodine atoms per unit and its glass transition temperature was determined to be ∼50°C, a temperature lower than that for the pris tine polymer (∼90°C), proving the higher rigidity of the complex conferred by links between ferrocenium units and iodide ions [378].…”

“…Espada et al [377] and Pannell et al [378] prepared poly(ferrocenylenesilylene)s and poly(ferrocenylenegermylene)s (Figure 36) by thermal ringopening of the appropriate ferrocenophane, and treated their thin films (0.1-0.2 μm thickness) with iodine vapor. The pale yellow color of the films turned dark upon iodine doping and the electrical conductivities were measured to be between 2.0 × 10 7 and 6.0 × ).…”

Polyferrocenylsilanes: synthesis, properties, and applications

“…121 The hole transport properties have been shown to be appreciable. 122,123 Further doping with I 2 saw the reversible formation of [I 5 ] À ions. 122,123 Further doping with I 2 saw the reversible formation of [I 5 ] À ions.…”

Co2(CO)6(μ,η2-HCCFc) as Precursor in the Synthesis of Multiredox Cyclic and Linear Vinylferrocenylsiloxanes

“…On the other hand, there is an increasing interest in preparing silicon-containing ferrocenyl polymers and macromolecules due to their applications as precursors to functional magnetic ceramics, conducting materials, electrode modifiers, and also electrochemical biosensors . In the last years, we have been exploring different routes for the preparation of new families of multimetallic macromolecular structures containing ferrocenyl moieties together with linear, polyhedral, and cyclic siloxanes. , One of our approaches to the preparation of such organometallic molecules was based on hydrosilylation reactions using Karstedt's catalyst.…”