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Keywords:

  • Rhodium;
  • Iridium;
  • N ligands;
  • Luminescence;
  • Photophysics;
  • Density functional calculations

Abstract

Rh and Ir complexes that contain meso-(p-methoxyphenyl)dipyrromethene (dipy) and phenylpyridine (ppy) ligands {i.e., [Rh(dipy)3], [Rh(ppy)2(dipy)] and [Ir(ppy)2(dipy)]} have been prepared and their electrochemical and luminescence behaviour are discussed and compared to results of theoretical calculations. The oxidation and reduction potentials, in agreement with the time-dependent (TD)-DFT calculations, indicate clearly that the HOMO–LUMO transitions are governed by the dipy ligand, which controls also the triplet excited-state emission. However, in luminescence, the two Rh complexes exhibit, in addition to a dipy-centred triplet emission, luminescence from the singlet excited state, which predominates at room temperature, due to a less important influence of the heavy-metal effect in Rh than in Ir complexes. Although the TD-DFT results are in very good agreement with the experimental emission spectra from the dipy-centred triplet excited state, this is not the case for the absorption spectra of the complexes and free dipy ligand.