Photoluminescence of ruthenium complexes with molecules exhibiting twisted internal charge transfer states

The occurrence of dual fluorescence in ruthenium complexes containing dimethylaminobenzonitrile (DMABN) has been studied at liquid nitrogen and room temperatures. It was concluded that in the [RuII(NH3)5DMABN]2+, [RuIII(NH3)5DMABN]3+ and [RuII(bipy)2Cl(DMABN)]+ complexes (bipy ≡ bipyridyl) a typical twisted internal charge transfer (TCT) fluorescence of DMABN appears upon excitation on a π-π* ligand absorption band. The ratio of the two luminescence band intensities is modified with respect to the free ligand.