Design and synthesis of fluorescent 6-aryl[1,2-c]quinazolines serving as selective and sensitive on-off chemosensor for Hg 2+ in aqueous media

Abstract

Three fluorescent quinazolines thiophen-2-yl-5,6-dihydrobenzo-[4,5] imidazo[1,2-c]quinazoline (1), pyridin-3-yl-5,6-dihydrobenzo-[4,5]imidazo-[1,2- c]quinazoline (2) and phenyl-5,5′,6,6′-dihydrobenzo-[4,4′,5, 5′]imidazo-[1.1′,2-c,2′-c]quinazoline (3) have been synthesized. Structures of 1 and 3 have been authenticated crystallographically. Quinazolines 1-3 exhibit highly selective on-off switching for Hg 2+ ions. The fluorescence intensity displayed a linear relationship with respect to Hg 2+ concentration (0.1-1.0 μM; R 2 = 0.99) with detection limit of 2.0 × 10 -7 M. © 2012 Published by Elsevier Ltd.