Synthesis and Luminescence of Rh III (phpy) 2 (E∪O) Complexes with phpyH = 2-Phenylpyridine and E∪OH = Tropolone, Flavonol and Lumichrome

The complexes Rh III (phpy) 2 (E∪O) with phpy− = deprotonated 2-phenylpyridine and E∪O− = bidentate anions of the biologically important compounds E∪O (troH = tropolone, flaH = flavonol and lumH = lumichrome) have been prepared and characterized with regard to their optical properties. The Rh III (phpy) 2 fragment is a useful probe for the emission behavior of these complexes since the phpy IL triplet can serve as a marker. Only the IL states of tp − and lum − are located below the phpy IL states. While Rh III (phpy) 2 (fla) is quite remarkable because it shows an IL (fla) fluorescence, Rh III (phpy) 2 (lum) displays an IL (lum) phosphorescence as expected owing to the heavy-atom effect.