Investigations On Synthesis And Properties Of Two-photon Fluorescent Sensors

Among various conventional bio-imaging techniques, multiphoton excited microscopy has found a niche as the best noninvasive fluorescence microscopic technique in tissue explants and living animals for its depth discrimination capability and higher spatial resolution. Herein, the technique and conventional organic molecule sensor were combined; a series of two-photon fluorescent probes based on Schiff base and heptamethine cyanine dyes was developed and their fluorescent recognition towards metal ions was studied.The main contents can be presented as follows:1. The research background of fluorescent chemosensors is concisely reviewed. Next it is mainly focused on the research progress of two-photon fluorescence microscopic technique and the classification of aluminum and palladium ions fluorescent sensors.2. A salicylimine-based two-photon probe for Al3+ has been synthesized. The response of Al3+ to L1 is excellent in aqueous solution and is free from disturbance by other ions. The two-photon fluorescence microscope imaging shows that the probe is membrane and can detect intracellular Al3+.3. Based on the work in the previous chapter, in order to optimize the properties of probe, a series of salicylimine-based two-photon Al3+ probe L2-L7 was synthesized. Meanwhile, the influence of different substitutions on the coordination properties and fluorescence properties was discussed. The results show that hydroxy-substituted ligand L3 and L7 possess better properties.4. Two reaction-based Pd0 two-photon sensors CyM and CyS have been synthesized and measured in aqueous solution. Pd0-mediated allylic ester C-O bond cleavage offers excellent selectivity, turn-on fluorescent response and enlarged two-photon cross section.