Electronic property and molecule design for luminescent metal complexes of tris(8-hydroxyquinoline) gallium

By means of ab initio HF and DFT B3LYP methods, the structure of Gaq(3) (q = 8-hydroxyquinoline) was optimized. The frontier molecular orbital characteristics and energy levels of Gaq(3) have been analyzed systematically in order to study the electronic transition mechanism in Gaq3. Three derivatives of Gags and their polymers were designed and the possibilities that they were employed as luminescent materials were discussed. The regularities and characteristic of energy bands of Gag, and its derivatives were also investigated. The results show that the electronic pi-pi* transitions in Gaq(3) are localized on the quinolate ligands. The emission of Gaq(3) is due to the electron transitions from a phenoxide donor to a pyridyl acceptor. Two possible electron transfer pathways are presented, one by carbon atoms, and the other via metal cation Ga3+. The derivatives of Gaq(3) may possess high luminescence efficiency.