Dimerization of Monofunctionalized Poly(ethylene oxide) via Metal-Ligand Interactions and Hydrogen Bonds

Tziatzios, Christos; Precup, Andrei A.; Lohmeijer, Bas G. G.; Boerger, Lars; Schubert, Ulrich S.; Schubert, Dieter

Abstract:

Supramolecular chemistry utilizes noncovalent bonds for assembling large ordered structures. Among the interactions used, metal–ligand interactions and hydrogen bonds play important roles. We have studied the degree of association attainable with these two interactions by quantifying dimer formation between suitable bond-forming blocks which were covalently linked to a poly(ethylene oxide) chain (or a dye-labelled derivative). Dimer formation was monitored by sedimentation equilibrium analysis in the analytical ultracentrifuge. The partial specific volume, v, of the compounds was also determined by equilibrium sedimentation, using the buoyant density method and the tetrahydrofuran/propylene carbonate solvent pair. Up to complete dimerization of the molecules was observed when complex formation was based on Fe(II)–terpyridine interactions. In contrast, under our experimental conditions, quadruple hydrogen-bonded arrays led to only 20–50% dimerization, with surprisingly low yields in apolar solvents and significant yields even in solvents also capable of participating in hydrogen-bond formation. With the compound studied, dimer formation was found to be largely irreversible.

Year:

2004

Type of Publication:

Article

Keywords:

Supramolecular chemistry; Metal ligand interactions; Hydrogen bonding; Sedimentation equilibrium analysis; Partial specific volume

Journal:

Progress in Colloid and Polymer Science

Volume:

127

Pages:

54 - 60