A series of cyclometalatating ligands were prepared based on the tridentate dqp (dqp is 2,6-di(quinolin-8-yl)pyridine). Teh ligand platform enables unusual large bite angles and, thus, octahedral coordination mode around the Ru center. The heteroleptic Ru complexes feature C1-symmetry due to the symmetry-breaking by the peripheral five- or six-membered carbanionic chelate (phenyl, naphthyl or anthracenyl units). The chelation mode is controlled by the steric effect and C-H activation selectivity of the ligand. Optimized conditions were developed to achieve high overall yields (55 to 75%) including a simplied purification protocol, <i>i.e.</i>, facile chromatographic separation using commercially available amino-functionalized Silica applying non-aqueous salt-free conditions to omit the necessity of counter-ion exchange. The structural, photophysical and electrochemical properties are presented. Notably, red-shifted absorption (up to 750 nm) and emission wavelengths in the IR (800 to 1000 nm) were found combined with prolonged emission lifetimes (up to 20 ns) in comparison to classical tpy-based (tpy is 2,2':6',2''-terpyridine) complexes. An enhanced stability was observed by blocking the reactive positions of the carbanionic ligand framework, while the reactive positions may be exploited for further functionalization.

Tridentate π-extended carbanionic donor sets for Ru<sup>II</sup> polypyridyl-type photosensitizer

254th National Meeting (2017)

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Tridentate π-extended carbanionic donor sets for RuII polypyridyl-type photosensitizer

Tridentate π-extended carbanionic donor sets for Ru^II polypyridyl-type photosensitizer