Rings and Chains: Synthesis and Characterization of Polyferrocenylmethylene.

Tamara Winter,Alexander Schießer,André Schäfer,Volker Presser,Wasim Haider,Markus Gallei

doi:10.1002/marc.202000738

Abstract

The synthesis and characterization of polyferrocenylmethylene (PFM) starting from dilithium 2,2-bis(cyclopentadienide)propane and a Me2 C[1]magnesocenophane is reported. Molecular weights of up to Mw = 11700g 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.

Highlights

Schießer Mass Spectrometry, Department of Chemistry Technische Universität Darmstadt Alarich-Weiss-Straße 4, Darmstadt 64287, Germany polymer architecture can occur upon functionalization of the polymer backbone or the redox-active moiety can be laterally bonded to the polymer chains
The 1H-nuclear magnetic resonance (NMR) spectrum exhibits two signals at δ 1H = 1.74 and 4.12 ppm corresponding to the methyl groups and Cp protons, respectively, the latter coinciding with a singlet, similar to what has been observed for the silicon analog poly(ferrocenyldimethylsilane), PFS.[14]
The 13C-NMR spectrum shows two resonances for the aliphatic carbon atoms at δ 13C = 30.7 and 33.5 ppm, and three resonances at δ13C = 66.4, 67.7, and 101.2 ppm corresponding to the aromatic carbon atoms of the Cp groups

Summary

Introduction

The synthesis of polyferrocenylmethylene (PFM) 1 was carried out via two different routes, starting either from a C[1]magnesocenophane or the dilithiated 2,2-bis(cyclopentadienide)propane analog and iron(II)-chloride and iron(II)-bromide (Scheme 1). The obtained PFM from the Me2C[1]Cp2Mg + FeBr2 reaction was analyzed via SEC MALLS to gain more insights into the absolute molar mass.

Results

Conclusion