title: A novel fluorescent 'off-on-off' probe for relay recognition of Zn2+ and Cu2+ derived from N,N-bis(2-pyridylmethyl)amine.
abstract: A metal-to-metal relay recognition was discovered with sequence specificity via a fluorescence 'off-on-off' phenomenon. We present here the synthesis of a new N,N-bis(2-pyridylmethyl)amine-based fluorescent sensor termed NBPA and its application as a selective relay probe for sensing of free trace zinc and copper ions. The addition of Zn(2+) to NBPA causes a drastic enhancement of fluorescent intensity by the formation of a 1 : 1 NBPA-Zn(2+) complex whereas other cations have no response. Moreover, Cu(2+) can induce fluorescence quenching in the NBPA-Zn(2+) system by the formation of a 1 : 1 NBPA-Cu(2+) complex confirmed by Job's Plot. The signal change of the sensor is based on the chelation-enhanced fluorescence (CHEF) effect of NBPA-Zn(2+) with the inhibition of the photoinduced electron transfer (PET) effect and the paramagnetic nature of Cu(2+) to the NBPA-Zn(2+) system. Under optimized conditions, the fluorescence intensity is linear to the concentration of Zn(2+) and Cu(2+) separately, exhibiting good linearities from 1.0 × 10(-6) M to 8.0 × 10(-6) M and 1.0 × 10(-6) M to 1.0 × 10(-5) M (R(2) = 0.9996 and R(2) = 0.9914) with detection limits of 7.89 × 10(-7) M and 1.27 × 10(-7) M, respectively. Furthermore, the rapid, selective feature enables the proposed sensor to be promising in monitoring Zn(2+) and Cu(2+) in biological and environmental research with good accuracy and precision.
authors: College of Chemistry, Jilin University, Changchun 130023, People's Republic of China. yfhuan@jlu.edu.cn.
authors: Yameng
authors: Y
authors: Liu
authors: Qiang
authors: Q
authors: Fei
authors: Hongyan
authors: H
authors: Shan
authors: Minghui
authors: M
authors: Cui
authors: Qing
authors: Q
authors: Liu
authors: Guodong
authors: G
authors: Feng
authors: Yanfu
authors: Y
authors: Huan
mesh_terms: D003300:Copper / Q000032:analysis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000032:analysis* / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; C000599032:N,N-bis(2-pyridylmethyl)amine; D011725:Pyridines; D003300:Copper; D015032:Zinc