Soluble Poly(ferrocenylenevinylene) with t-Butyl Substituents on the Cyclopentadienyl Ligands via Ring-Opening Metathesis Polymerization

Abstract

Soluble poly(ferrocenylenevinylene) (PFV) 6 was synthesized via ring-opening metathesis polymerization (ROMP) of ansa-(vinylene)ferrocene Fe(η-C5H3tBu)2C2H2 (5) with tBu substituents on the cyclopentadienyl (Cp) ligands. Monomer 5 was obtained through intramolecular dicarbonyl coupling of the corresponding ferrocene-dicarbaldehyde, 1,1‘-di-t-butyl-3,3‘-dicarbaldehyde, Fe(η-C5H3tBu)(CHO)2 (4) in the presence of the McMurry reagent. Both monomer precursor 4 and monomer 5 were structurally characterized by 1H and 13C NMR spectroscopy, X-ray crystallography, mass spectrometry, and elemental analysis. ROMP of 5 was investigated using molybdenum-based (Schrock-type) and ruthenium-based (Grubbs-type) initiators under various conditions and was monitored by 1H NMR spectroscopy. Soluble polymers with low or high molecular weight were obtained and completely characterized. Photolytic and thermal ring-opening polymerizations of 5 were also attempted, but only unreacted monomer was isolated under these conditions. Th...