A multifunctional selective "turn-on" fluorescent chemosensor for detection of Group IIIA ions Al, Ga and In

A versatile chemosensor 1 ( E )-2-(((8-hydroxy-2,3,6,7-tetrahydro-1 H ,5 H -pyrido[3,2,1- ij ]quinolin-9-yl)methylene)amino)-1 H -benzo[ de ]isoquinoline-1,3(2 H )-dione, based on naphthalimide and julolidine moieties, was developed for highly distinguishable and selective recognition of Group IIIA metal ions (Al 3+ , Ga 3+ and In 3+ ). Sensor 1 exhibited significant 'off-on' fluorescence responses at 488 nm in the presence of Al 3+ and at 570 nm in the presence of Ga 3+ and In 3+ . The same emission of Ga 3+ and In 3+ could be distinguished through different color changes (from colorless to yellow for Ga 3+ and no color change for In 3+ ). Binding constants of 1 for Ga 3+ and In 3+ are the highest reported to date for an organic chemosensor. A 2 : 1 binding mode between 1 with Al 3+ , Ga 3+ and In 3+ is proposed based on electrospray ionization mass spectrometry, Job plot analysis, and theoretical calculations. A versatile chemosensor was developed for highly distinguishable and selective recognition of group IIIA metal ions (Al 3+ , Ga 3+ and In 3+ ).