•The quenched fluorescent probe recognition of Cu2 + shows the reversibility and selective.•The fluorescent probe forms a 1:1 binding stoichiometry with Cu2 +.•The probe responses to Cu2 + with a very low detection limit of 1.94 × 10− 7 M.•The probe can be suitable for imaging in living cells, and shows low toxicity.A new pyrazoline-based probe D was designed and synthesized, which can be used as a highly sensitive, selective and reversible recognizing fluorescent to detect Cu2 +. The recognition properties of this compound was investigated by UV–vis absorption and fluorescence spectrophotometry. The results showed that the probe D forms a 1:1 complex with Cu2 + and displayed a linear fluorescence response to Cu2 + with a detection limit of 1.94 × 10− 7 M. In addition, the probe have a good biocompatibility in living cells.Download high-res image (296KB)Download full-size image

•C–H arylation of indole with aryl diazonium salts was catalyst by Rhodamine B.•This method only requires green light and room temperature.•The mechanism of this reaction relies on free radical reaction.In this Letter, we present the Rhodamine B catalyzed direct C–H arylation of indole with aryl diazonium salts. This method only requires green light and room temperature.

Various substituted diarylether derivatives were prepared by using heterogeneous reusable Cu2O- and Cu-coated carbon nanotubes (Cu2O/Cu-CNTs) as catalyst under ligand-free conditions, which provided good to excellent yields. The catalyst was characterized by TEM, XRD, and AAS analysis. The effects of solvent, base, and amount of catalyst for the O-arylation were investigated. The catalyst could be recovered by simple filtration from the reaction mixture without further treatment and reused several times with consistent catalytic activity. In addition, CNTs could also be recovered from the used Cu2O/Cu-CNTs by a simple acid treatment.