L-lactide polymerization utilizing a hydroxy-functionalized 3,6-bis(2-pyridyl)pyridazine as supramolecular (Co)initiator: Construction of polymeric [2x2] grids

A hydroxy-functionalized 3,6-bis(2-pyridyl)pyridazine ligand was synthesized from 3,6-bis(2-pyridyl)tetrazine and 5-hexyn-1-ol. This ligand was subsequently polymerized with L-lactide utilizing a controlled aluminum alkoxide-based polymerization. The resulting poly(L-lactide) macroligands were characterized with H-1 NMR spectroscopy, IR spectroscopy, gel permeation chromatography, and MALDI-TOF-MS, revealing the successful incorporation of the ligand into the polymer chains. Complexation studies of both the hydroxy-functionalized ligand and the macroligands were performed by UV-vis spectroscopic investigations, demonstrating the exclusive formation of metallo-supramolecular gridlike architectures. In addition, AFM measurements also revealed the existence of the defined polymeric species.