Hyperbranched Poly(ferrocenylphenylenes):  Synthesis, Characterization, Redox Activity, Metal Complexation, Pyrolytic Ceramization, and Soft Ferromagnetism

Abstract

Hyperbranched poly(ferrocenylphenylenes) (hb-PFPs) with high molecular weights were synthesized by the copolycyclotrimerizations of (E,E)-1,1‘-bis[2-(4-ethynylphenyl)vinyl]ferrocene (1) with (E)-1-[2-(4-ethynylphenyl)vinyl]ferrocene (2) catalyzed by TaCl5−Ph4Sn at room temperature in high yields (up to 97%). Effects of reaction conditions, such as monomer and catalyst concentrations, reaction time and molar feed ratio (r 1 / 2 ), on the copolycyclotrimerization were investigated. Solubility of the copolymer is decreased with an increase in its content of diyne component (N 1 /N 2 ). The hb-PFPs were characterized by IR, NMR, UV, CV and TGA analyses. The copolymers are redox active, whose oxidation potentials are decreased with an increase in N 1 /N 2 . They are thermally stable, losing ∼5% of weights when heated to 384−400 °C and retaining ∼70% of weights when pyrolyzed at 1200 °C. The complexation with cobalt carbonyl further metallizes the hb-PFPs and the pyrolytic ceramization of the cobalt−polymer complexes yields soft ferromagnetic ceramics with high magnetizability (M s up to ∼126 emu/g) and low coercivity (H c down to ∼0.068 kOe).

Polynorbornenes Containing Ferrocene Derivatives and Alkyne‐bis(tricarbonylcobalt)

“…Since ferrocene, η 6 ‐benzene‐η 5 ‐cyclopentadienyliron and alkyne–cobalt carbonyl complexes are known to possess electrochemical behavior, we used cyclic voltammetry to determine if this would be evident in our structures 21, 24. The cyclic voltammogram of complex 7 (Figure 1C) displayed an E 1/2 = 0.69 V (vs. Ag/AgCl) corresponding to the reversible oxidation of the ferrocene moiety to a ferrocenium ion moiety.…”

“…Recently, Al‐Badri and Tew23 reported that oxonorbornene containing cobalt carbonyl protected alkynes could be polymerized using the third generation Grubbs' catalyst. Also, Tang and coworkers24 has found that ceramics prepared from cobalt carbonyl containing ferrocene compounds possess interesting ferromagnetic properties. With this in mind, the preparation of organoiron polynorbornenes containing µ‐alkyne‐bis(tricarbonylcobalt) has the potential to produce functional materials with unique electrical and magnetic properties.…”

Synthesis, Chiroptical, and Redox Properties of Ferrocene‐Containing Optically Active Polymers

“…The redox patterns are complicated compared with that of ferrocene (Figure S22, Supporting Information) presumably due to the presence of various electrically active functional groups including iodo, amino acid, and phenyleneethynylene moieties. The peaks around 0.05 V are assignable to ferrocene moieties in the charts of 1 m , poly( 1 m ‐ 2 ), poly( 1 m ‐ 3 ), although the reversible redox patterns are not clear compared to previously reported ferrocene‐containing π‐conjugated polymers such as poly(ferrocenylenevinylene) substituted with tert ‐butyl groups and hyperbranched poly(ferrocenylphenylenes) . It is considered that intermolecular interactions such as hydrogen bonding and π‐stacking are also responsible for unclarity in the redox peaks of the present monomers and polymers.…”

Progress on the synthesis and catalytic and anti‐migration properties of ferrocene‐based burning rate catalysts

“…Ferrocene‐containing polymers were synthesized and applied in numerous field, while there are only a few reports of the application of such polymers in solid composite propellants as BR catalysts, even though ferrocene‐containing polymers and related materials present enormous potentiality in this field.…”