Optical and electrochemical properties and the calculated structure of pentacoordinate aluminum 8-hydroxyquinoline

► A series of pentacoordinate AlQ2X compounds were synthesized and characterized. ► The compounds would facilitate the retarding of the quenching effect to enhance quantum efficiency. ► The λmaxs of absorption and emission for AlQ2X were similar to those of AlQ3. ► The molecular orbitals working in absorption and emission for AlQ2X are similar to those of 8-HQ itself