title: A novel colorimetric and fluorescent "off-on" chemosensor for Cu2+ based on a rhodamine derivative bearing naphthyridine group.
abstract: A new rhodamine-based derivative bearing a naphthyridine group (compound 1) was synthesized as a colorimetric and fluorescent "off-on" chemosensor for Cu(2+) in aqueous solutions. The sensing behaviors of 1 toward various metal ions in neutral aqueous solutions were investigated by absorption and fluorescence spectroscopies. Compound 1 is found to exhibit a significant increase in absorbance at 561 nm and an amplified fluorescence at 590 nm toward Cu(2+) in a selective, sensitive and rapid manner. The quantification of Cu(2+) by 1 using an absorption spectroscopy method was satisfactory in the linear working range 0.9-10 μM, with a detection limit of 5.4 × 10(-8) M for Cu(2+) and good tolerance of other metal ions. Upon addition of Cu(2+), the spirolactam ring (colorless and nonfluorescent) of 1 was opened to ring-opened amide (red color and fluorescent) and a 1:1 stoichiochemetry for the 1-Cu(2+) complex was formed with an association constant of 1.57 × 10(4) M(-1).
authors.affiliation: College of Sciences, Henan Agricultural University, Zhengzhou 450002, People's of Republic China. pxie2007@yahoo.com.cn
authors.forename: Puhui
authors.initials: P
authors.lastname: Xie
authors.forename: Yue
authors.initials: Y
authors.lastname: Xiao
authors.forename: Denghui
authors.initials: D
authors.lastname: Yao
authors.forename: Qiu
authors.initials: Q
authors.lastname: Jin
authors.forename: Fengqi
authors.initials: F
authors.lastname: Guo
mesh_terms: D003124:Colorimetry / Q000295:instrumentation*; D003300:Copper / Q000032:analysis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy; D009287:Naphthyridines / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D005456:Fluorescent Dyes; D009287:Naphthyridines; D012235:Rhodamines; D003300:Copper