The Synthesis And Properties Of Relay Fluorescent Probes Based On 1,8-Naphthalimide

As a traditional dyes and dyes, studies on naphthalimide derivatives have been reaching maturity. Yellow-green light district Naphthalimide synthetic derivatives have low cost, good performance characteristics of the light-emitting and the light-emitting more concentrated in the visible range, is an ideal fluorescent probe molecules luminescent groups; At the same time, because the seats Schiff base compounds introduced C=N structure of these compounds gives excellent binding ability. From the perspective of molecular design to naphthalimide fluorophoce group as to the Schiff base structure as a recognition group, two probes were designed and synthesized compounds P1 and P5, and their optical properties and probe performance were explored.Properties of P1 found that in THF/H2O（95/5, v/v） solution, probe P1 exhibit a selective fluorescence quenching to Fe³⁺ and the degree of fluorescence quenching with a linear relationship between the concentration of Fe³⁺; meanwhile, non-luminous metal complexe P1-Fe³⁺ can be selectively enhanced by PO^3-₄, the luminous of system also have a linear relationship between the concentration of PO^3-₄. This shows that the probe P1 able selective sensing Fe³⁺ and PO^3-₄ by the mode of fluorescent “on-off-on”, indicating that the probe P1 is a kind of relay recognition fluorescent molecular probe. Calculated by statistical methods for the detection of Fe³⁺ and PO^3-₄ limits were as low as 1.282×10-6 mol/L and 1.721×10-6 mol/L; by titration curves and mass spectrum analysis and other work variety of ways to determine the stoichiometry of ligand P1 and Fe³⁺ ratio of 1:1; also designed three ancillary ligand P2, P3, P4, by a method of control of a single variable and P1-Fe³⁺ coordination sites were explored; by mass spectrometry analytical method to determine the reasons for the enhancement PO^3-₄ is to capture the complex Fe³⁺ to achieve.Performance by P5 probe found that in THF/H2O（95/5, v/v） solution, Fe³⁺ and Cu²⁺ two structural elements of metal ions can lead to fluorescence quenching of P5, which suggests P5 does not exist for a specific cations sensor. But metal complexes P5-Fe³⁺ and P5-Cu²⁺ fluorescence enhancement by PO^3-₄and H2PO– 4 respectively, and the sensing process without interference from other anions and cations. Both the two kinds of metal complexes have the ability of linear sensing for PO^3-₄ and H2PO– 4. The detection limits of PO^3-₄ and H2PO– 4 are 5.611×10-7 mol/L and 1.683×10-6 mol/L respectively.