Synthesis of 4′-Functionalized 2,2′:6′,2′′-Terpyridines via the Pyridone Route: Symmetric and Asymmetric Bis-Complex Formation

2,2':6',2''-Terpyridines functionalized in the 4'-position, e.g, I, have been prepd. by reaction of 2,6-bis-(pyrid-2-yl)-4-pyridone under basic conditions with different electrophiles. The electrophiles consist of functionalized alkyl chains, which are terminated with different anionic leaving groups such as bromides, chlorides and tosylates. These reactions yielded terpyridines, which were modified at the 4'-position with heptoxy-, bromodecanoxy-, cyanopropoxy-, allyloxy-, styrene-4-ethoxy-, as well as (methoxyethoxy)-ethoxy functionalities. In an approach towards new functional materials based on polymerizable bis-terpyridyl metal-ion complexes, the 4'-epoxy-methoxy terpyridine was complexed with Co(II) in order to yield the paramagnetic bis-complex, which still could be characterized via 1H NMR spectrometry. Addnl., in order to obtain an asym. bis-complex with two different terpyridine ligands, methyl-diethyleneoxy-terpyridine-Ru(II)-terpyridine-oxyheptane was prepd. utilizing a directed coupling method via Ru(III)/Ru(II) chem.