New fluorescent and colorimetric chemosensors bearing rhodamine and binaphthyl groups for the detection of Cu2+

New rhodamine derivatives bearing binaphthyl group were synthesized as selective fluorescent and colorimetric sensors for Cu2+. Highly selective “off–on” type fluorescent changes were observed upon the addition of Cu2+. Selective fluorescent enhancement of two rhodamine derivatives was attributed to ring opening from the spirolactam (nonfluorescent) to ring-opened amide (fluorescent). A chemo-sensing based on rhodamine derivative was further applied to the microfluidic system.