AIE active quinazoline based probes for selective detection of Fe3+ and acidochromism

Synthesis of 6-(4-(4-(pyridin-2-yl)piperazin-1-yl)phenyl)-5,6-dihydrobenzo-[4,5]-imidazo[1,2–c]quinazoline (P1) and 6-(4-(4-(pyrimidin-2-yl)-piperazin-1-yl)phenyl)-5,6-dihydro-benzo[4,5]imidazo[1,2–c]quinazoline (P2) which have been thoroughly characterized by spectroscopic studies (IR, 1H, 13C, ESI–MS, UV/Vis and fluorescence). AIE behaviour of P1 and P2 has been investigated by absorption and emission spectroscopy in THF/-water mixture by varrying water fraction. In addition, P1 and P2 serve as highly selective and sensitive fluorescence sensor for Fe3+ and also show promising reversible acidochromism. The Job’s plot analysis shows 2:1 binding stoichiometry between the metal centre Fe3+ and P1-P2. The limit of detection (LOD) is being found 2 x 10-7 for P1 and 3 x 10-7 for P2.