1,8-Naphthyridine Modified Rhodamine B Derivatives: Turn-On Colorimetric Sensor for Cu2+

A 1,8-naphthyridine modified rhodamine B derivative, one Cu2+-selective chemosensors was designed, synthesized and characterized, which display a high selectivity for Cu2+ among environmentally and biologically relevant metal ions. It can detect Cu2+ in aqueous solution selectively with a dramatic colour change from colorless to magenta. The detection mechanism involves a ring-opening process as a consequence of metal complex formation. Jobs plots study indicated that the chemosensor chelated Cu2+ with 2:1 stoichiometry.