Mixed iridium(III) and ruthenium(II) polypyridyl complexes containing poly(eta-caprolactone)-bipyridine macroligands

A hydroxy-functionalized bipyridine ligand was polymerized with -caprolactone utilizing the controlled ring-opening polymerization of -caprolactone in the presence of stannous octoate. The resulting poly(-caprolactone)-containing bipyridine was characterized by 1H NMR and IR spectroscopy, and gel permeation chromatography, as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, revealing the successful incorporation of the bipyridine ligand into the polymer chain. Coordination to iridium(III) and ruthenium(II) precursor complexes yielded two macroligand complexes, which were characterized by NMR, gel permeation chromatography, matrix-assisted laser desorption/ionization time-of-flight MS, cyclic voltammetry, and differential scanning calorimetry. In addition, both photophysical and electrochemical properties of the metal-containing polymers proved the formation of a trisruthenium(II) and a trisiridium(III) polypyridyl species, respectively.