New Fluorescent Probes For Cation Detection Based On Porphrin, Naphthalimide And Quinoline Derivatives

The analysis and detection of the transition metal ions are currently of significant importance for chemistry because of its implications in many fields: chemistry, biology, medicine (clinical biochemistry), environment, etc. As a link of material science and analytical chemistry, the study in fluorescent sensor and novel sensor material has received a growing attention with the rapid development of cross subject. They provide accurate, on-line, and low-cost detection of cations with high selectivity and sensitivity and have been used in a variety of fields such as environmental chemistry, analytic chemistry, and bio-medicinal science.Porphyrins are attractive candidates of fluorescent probes owing to their good photophysical properties with strong fluorescence, large Stokes shifts and relatively long excitation (> 400 nm) and emission (> 600 nm) wavelengths that minimize the effects of the background fluorescence. A porphyrin derivative containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of zinc ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, the porphyrin derivative exhibits unexpected ratiometric fluorescence response to Zn²⁺ with high selectivity. The analytical performance characteristics of the proposed Zn²⁺-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn²⁺ with a linear range covering from 3.2×10^-7 to 1.8×10^-4 mol/L and a detection limit of 5.5×10-8 mol/L. The experiment results show that the response behavior of the porphyrin derivative to Zn²⁺ is pH-independent in medium condition (pH 4.0-8.0) and show excellent selectivity for Zn²⁺ over transition metal cations.Aminonaphthalimide derivatives are attractive fluoroionophore owing to their good photophysical properties with strong fluorescence, large Stokes shifts and relatively steady emission wavelengths. We design and synthesis a novel chemosensor with high selectivity and sensitivity based on Hg²⁺-induced photoinduced electron transfer (PET). A new Aminonaphthalimide derivative has been designed and synthesized as chemosensor for recognition of mercury ions. The analytical performance characteristics of the proposed Hg²⁺-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Hg²⁺ with a linear range covering from 6.8×10^-7 to 5.2×10^-4 mol/L and a detection limit of 3.2×10^-7 mol/L.A ratiometric fluorescent zinc probe 1 of carboxamidoquinoline with a carboxylic acid group was designed and synthesized. Probe 1 exhibits high selectivity for sensing Zn²⁺; about a 13-fold increase in fluorescence emission intensity and an 82 nm red-shift of fluorescence emission are observed upon binding Zn²⁺ in EtOH/H₂O (1:1, v/v) solution. The ratiometric fluorescence response is attributed to the 1:1 complex formation between probe 1 and Zn²⁺ which has been utilized as the basis for the selective detection of Zn²⁺. The analytical performance characteristics of the proposed Zn²⁺-sensitive probe were investigated. The linear response range covers a concentration range of Zn²⁺ from 2.0×10^-6 to 5.0×10^-5 mol/L and the detection limit is 2.7×10^-7 mol/L. The determination of Zn²⁺ in both tap and river water samples shows satisfactory results.