Synthesis of a highly selective bis-rhodamine chemosensor for naked-eye detection of Cu2+ ions and its application in bio-imaging

A bis-rhodamine based fluorescent chemosensor for naked-eye detection of Cu2+ with enhanced sensitivity as compared to mono-rhodamine derivative has been synthesized, and its selectivity for Cu2+ in the presence of other competitive metal ions (Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, Cr3+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, and Pb2+), and application in bio-imaging are demonstrated.

► The sensitivity and selectivity for Cu2+ ions of two chemosensors compared.
► The structure of Cu2+-bis-rhodamine complex has been determined.
► NMR, EPR, UV, Fluorescence and energy minimization studies confirm the structure.
► The sensor is stable over a broad range of pH.
► The chemosensor is useful for the imaging of bacteria exposed to Cu2+ ions ion.