Syntheses and photophysical properties of visible-light-absorbing Ru(II) polypyridyl complexes possessing (pyridylpyrazolyl)metal tethers

Novel Ru(II) polypyridyl complexes possessing pyridylpyrazolyl tethers were synthesized. Reactions with various organometallic precursors readily afforded multinuclear complexes which possess a light-harvesting Ru(II) core and (pyridylpyrazolyl)metal fragments in high yields. Analysis of the photophysical properties of the obtained multinuclear complexes revealed that the complexes had similar absorption and emission characteristics; however, their emission quantum yields decreased in proportion to the number of metal fragments. The di- and trinuclear complexes were stable under donating solvent such as CH3CN.