Synthesis And Properties Of Pyridyl Halide Fluorescent Probe Molecules

Amino acids and anions play a fundamental role in biological and environmental systems.Therefore,their selective recognition and sensing by artificial receptors is of paramount importance and a key topic in supramolecular chemistry.However,because of the molecular structure similarity of amino acids including spectral inertness,as well as no electrochemical activity,which make them is difficult to be selectived recognition in aqueous solution.For anions,due to the interference from other anions and hydrogenbonding interactions with water molecules,seriously hinders the development of anion chemosensors in aqeous solution.This thesis mainly focused on the pyridinium-based phenylenevinylene derivetives as chemosensor: 1)for detection of lysine and methionine in water and serum system through supramolecuar self-assembly and hostguest competitive interaction;2)for detection of BF4-and PF6-in water by non-covalent interactions such as ionic interaction;3)for detection of PPi anion in water by metalcoordination interaction.The main content in this thesis as following:(1)Pyridinium-based phenylenevinylene derived G1 with alkyl chain as the terminal group was synthesized by using 4-methylpyridine and terephthalaldehyde as raw materials.Supramolecular interactions between G1 and anions,cucurbit[6]uril and amino acids were studied by UV-vis absorption and fluorescence spectroscopy.The results showed that under the condition of p H = 6.0,the guest molecules G1 generated yellow fluorescent aggregates in the presnece of nitrate ions.The aggregates was disturbed when addition of TMe Q[6] or HMe Q[6] to the solution to form pseudorotaxane structure by host-guest interaction and accompany a green fluorescence.Further study found that this host-guest interaction can be applied to fluorescence recognition detection of lysine and methionine in water and serum system without being interfered by other amino acids and anions.(2)Pyridinium-based phenylenevinylene derivatives G2,G3 and G4 were synthesized.The results showed that the series of probes have significant fluorescence recognition to PF6-anions.However,when the alkyl chain length of the fluorescent probe is 7(G2),the detection signal of BF4-was not obvious.When alkyl chain chain is longer than 7(G3,G4),BF4-can be recognized by fluorescence signal change.The results indicated that the increasing length of the alkyl chain enhanced the hydrophobicity of the probe molecule and facilitates its aggregation under the target anion which comes out a clear fluorescence recognition signal.(3)Probes G6 and G7 were synthesized in a similar routes,fluorescence spectroscopy and UV-Vis absorption spectroscopy were used to study the recognition effect of the probe on anions and cations.We found that probe G6 and G7 were able to detect zinc ions in aqueous solution without being interfered by other ions.Most importantly,probe G7 with zinc ions in a 1: 1 mole ratio,it can be used to detect PPi over other common anions.