Blue emitting pentacoordinated Al(III) complexes based on 2-methylquinolin-8-olate and substituted phenolate ligands. The role of phenolate derivatives on emission and absorption properties.

This paper reports the synthesis, characterisation and photophysical investigation of the homologous series of blue-emitting pentacoordinated AlQ'(2)L complexes 1-6, where Q' is 2-methylquinolin-8-olate and L is a phenolate substituted in para to the oxygen donor atom. Both electron attracting and electron releasing substituents have been considered. Also binuclear complexes of formula Q'(2)Al-L'-AlQ'(2), where L' = OC(6)H(4)C(6)H(4)O, OC(6)H(4)(CH(2))(3)C(6)H(4)O and OC(6)H(4)C(CH(3))(2)C(6)H(4)C(CH(3))(2)C(6)H(4)O have been synthesised and characterised. These are interesting blue-emitting materials for OLED (organic light emitting diode) fabrication. A comparison between computational and experimental results allowed the description of the absorption and fluorescence processes. A study of the frontier orbitals involved in the electric conduction and fluorescence emission has been performed. Influences of the phenolate-based ligands on the compounds spectroscopy have been particularly taken into account.