Studies On Fluorescent Sensors Based On Phenanthroline Derivatives Containing Electron Donor Or Acceptor

1,10-phenanthroline and its derivatives, which possess a large conjugated planar structure, pronounced chemical, photochemical and electrochemical properties, are very important structural unit to build supramolecular systems.In this paper, the photophysical properties of supramolecular systems formed by phenanthroline derivatives and perylene diimide derivative PASP have been studied. Meanwhile, the supramolecular system formed by phenanthroline complex and PASP as fluorescent probe for detecting anions has been studied. The interesting results are listed as follows:1. Derivatives of 1, 10-phenanthroline dpapz, mdpapz and mdbapz are prepared and the interactions between them and PASP are studied. UV-Vis absorption spectral results indicate that dpapz associates with PASP mainly by π-π stacking, while mdpapz associates with PASP mainly through electrostatic interaction. Fluorescence spectral results demonstrate that phenanthroline derivatives can quench the fluorescence of PASP. They may form 1: 1 supramolecular complexs, with binding constants of 2.94×104 to 1.30×106 M-1. Photoinduced electron transfer from PASP to phenazine derivatives is confirmed by electrochemical, electron paramagnetic resonance(EPR) and time-resolved fluorescence experiments respectively. Both the trends of electron transfer rate constant(k ET) and efficiency(ΦET) are mdpapz > mdbapz > dpapz. TEM experimental results show that PASP and phenanthroline derivatives can be assembled to form needle-like or rod-like nanostructures. 2. Derivative of 1,10-phenanthroline p Bdpapz and its complex [Cu(p Bdpapz)2] are prepared and the interaction of [Cu(p Bdpapz)2] with PASP is studied. UV-Vis absorption spectral results indicate that [Cu(p Bdpapz)2] associates with PASP mainly through π-π stacking interaction. Fluorescence spectroscopy assay results demonstrate that [Cu(p Bdpapz)2] can quench the fluorescence of PASP. When the concentration ratio of [Cu(p Bdpapz)2] and PASP is 2.5, the fluorescence intensity of PASP is almost completely quenched. The binding constant between PASP and [Cu(p Bdpapz)2] is calculated to be 4.17×106 M-1. 3. The fluorescence response of the supramolecular system [Cu(p Bdpapz)2]/PASP towards glucose, fructose, sodium gluconate, sodium tartrate, sodium malonate,sodium succinate, sodium adipate and sodium citrate have been studied. The results show that the fluorescence intensity of the supramolecular system has been enhanced by a factor of 72 unpon addition of sodium citrate. While the addition of glucose and other substances have less impact on the fluorescence recovery of the supramolecular system, indicating that [Cu(p Bdpapz)2]/PASP supramolecular system has a higher selectivity for citrate ion.