Metallo‐Polymerization/‐Cyclization of a C₁₆‐Bridged Di‐Terpyridine Ligand and Iron(<scp>II</scp>) Ions

Abstract Summary: The coordinative polymerization/cyclization of a flexible monodisperse di‐terpyridine ligand with iron( II ) chloride is reported. Matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) investigations showed the preferred formation of a [2 + 2] macrocycle, but also larger aggregates (cycles or linear oligomers) with up to 10 monomer units were found. Because of its C 16 ‐spacer, the solubility is sufficient for performing viscosity experiments in CHCl 3 /MeOH solution. A viscosity titration revealed a maximum in viscosity at the 1‐to‐1 ratio of iron( II ) ions to di‐terpyridine‐ligands, which indicates the formation of extended oligomers, polymers, catenanes and/or cycles at that ratio. Schematic representation of intra‐ and intermolecular metallo‐macrocycles. magnified image Schematic representation of intra‐ and intermolecular metallo‐macrocycles.