Terahertz absorption spectra of 8-hydroxyquinoline and its some metal complexes

The room temperature terahertz (THz) absorption spectra of 8-hydroxyquinoline (8HQ) and tris(8-hydroxyquinolino)aluminum, bis-(8-hydroxyquinolinato)zinc and copper 8-hydroxyquinoline were clearly measured from 0.3 to 1.8 THz. 8HQ has absorption peaks which occur at 1.02, 1.48, and 1.77 THz. Density functional theory (DFT) was used to predict the vibration frequencies of 8HQ in the frequency range 0–10 THz. Metal complexes have various absorption peaks in the THz region, which may be related to different metal ions and used to distinguish them. These results show that THz-TDS are sensitive tools for characterization of metal complexes.