Rings and Chains: Synthesis and Characterization of Polyferrocenylmethylene

Abstract

The synthesis and characterization of polyferrocenylmethylene (PFM) starting from dilithium 2,2‐bis(cyclopentadienide)propane and a Me2C[1]magnesocenophane is reported. Molecular weights of up to Mw = 11 700 g mol–1 featuring a dispersity, Ð, of 1.40 can be achieved. The material is studied by different methods comprising nuclear magnetic resonance (NMR) spectroscopy, matrix‐assisted laser desorption/ionization time of flight (MALDI‐ToF) mass spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) measurements elucidating the molecular structure and thermal properties of these novel polymers. Moreover, cyclic voltammetry (CV) reveals quasi‐reversible oxidation and reduction behavior and communication between the iron centers. Also, the crystal structure of a related cyclic hexamer is presented.

Polycobaltoceniumylmethylene – A Water-Soluble Polyelectrolyte Prepared by Ring-Opening Transmetalation Polymerization

“…Annealing of 1-Cl at 130 °C for 24 h showed no influence on its molecular weight distribution, demonstrating the high thermal stability of 1-Cl . The results were in the same range as the reported molecular weights obtained for the corresponding PFM system ( M n = 8.3 × 10 3 g mol –1 , M w = 11.7 × 10 3 g mol –1 ) . PXRD measurements indicate that the obtained product is amorphous; however, a strong X-ray fluorescence is observed, originating from the Co atoms (Figure S18).…”

“…At 540 °C, the residual weight was constant, with a comparably high ceramic yield of ca. 56 wt % . In the presence of oxygen, degradation also starts at 185 °C, while two additional decomposition steps were observed at 290 and 440 °C.…”

“…47 The 1 H NMR spectrum of 1-Cl (in D 2 O) revealed two broad resonances at 5.60 and 5.66 ppm for the cyclopentadienyl (Cp) protons and a singlet at 1.54 ppm corresponding to the methyl groups attached to the bridging carbon atom (Figure S3). Compared to the related polyferrocenyldimethylsilane (PFS) 1 and PFM 46 systems, the resonances of the Cp protons are low-field shifted due to the positively charged metal center. Compared to the cobaltocenium-based system reported by Manners et al 39 (5.43 ppm; 5.50 ppm), the resonances of 1-Cl are slightly low-field shifted, indicating a higher interaction of the cobaltocenium moieties due to the shortened bridging motif.…”

“…Regarding the application of metal-containing polymers as preceramic materials, ,, the thermal properties of 1-Cl were analyzed by TGA under a nitrogen atmosphere and under synthetic air (20.5% O 2 , 79.5% N 2 ; Figure S15). Interestingly, 1-Cl shows the same thermal behavior under both conditions up to 160 °C.…”

“…However, in 2021 we reported the synthesis of polyferrocenylmethylene (PFM) via the reaction of a carba [1]magnesocenophane with FeBr 2 . 46 Herein, we present the synthesis of the first polycobaltoceniumylmethylene chloride (PCM-Cl) by the reaction of Me 2 C[1]magnesocenophane with CoCl 2 in a ring-opening transmetalation polymerization (ROTP), followed by oxidation, to give 1-Cl in the form of a water-soluble green colored solid (Scheme 1).…”