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

Abstract

The complexes RhIII(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 RhIII(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 RhIII(phpy)2(fla) is quite remarkable because it shows an IL (fla) fluorescence, RhIII(phpy)2(lum) displays an IL (lum) phosphorescence as expected owing to the heavy-atom effect.