Synthesis Of Coumarin Containing Nitrogen Derivatives Based Fluorescent Probe

Coumarin compounds have physiological activities such as antibacterial anti-inflammatory, anti-tumor and so on. They are widely used in medicine, agrictural chemicals, food and some other fields.The molecules of coumarins have lactone structure, C=C double bonds and C=O double bonds. Lactone structure enhances the molecular rigidity, the existence of double bonds increases conjugate degree of moleculars. Therefore coumarin derivatives have very strong fluorescence in the visible light range, very high photons stability and photoluminescence quantum efficiency. So coumarin compounds can also be used as fluorescent whitening agents, fluorescent probes, etc. Coumarin containing heteracyclic ring, such as heterocyclic system containing nitrogen,might be used as fluorescent probes. fluorescent probes have wide applications in quinoline, rhodamine, pyridazine, pyridine, indole, etc. In these probes coumarin groups are fluorescence groups, nitrogen-containing compounds act as chelating groups. The introduction of amino, a strong electron donating group, on the seventh location of coumarins are beneficial to enhance fluorescence. Coumarin group is not only used as two functions of acceptors,but also chromophores. Not only the fluorescence intensity may be changed while they chelate metal ions, but the maximum emission wavelength might also be changed accordingly.The thesis designed and synthesized of a series of new coumarin derivatives containing nitrogen by Pechmann reaction and Mannich reaction, and the ultraviolet and fluorescence properties were studied. The thesis includes the following contents:(1)Synthesis of new coumarin containing nitrogen derivatives. A series of new nitrogen-containing coumarins were synthesized which coumarins were as back bond and heterocyclic were chosen as linking groups.And the products were characterized through IR,1H NMR, EA, etc..(2)The synthesis of target products intermediate 2, compound 3c and 3d were explored by using orthogonal experiment and control variable method and other methods. Catalyst, reaction temperature, reaction solvents, the dosing raio of raw materials were discussed in this paper, the influence of such factors as the best synthetic conditions were determined.(3)The UV and fluorescence properties were studied for part of the target products.The complexation of metal ions and discusses the mechanism of complexation with metal ions were studied. The resultsshow that the coumarin 7- to electronic group modification, increase the conjugate system and formation of coumarin structure can lead to the maximum absorption wavelength ultraviolet redshift with the structure characteristics. The target product 3a, 3d, 3e and 3f all showed this nature with the maximum absorption wavelength redshifting between 15 and 40 nm.Compound 3b has a good specificity recognition with Cu2+ which formation of 1:1 ratio of ligand complex. ultraviolet absorption wavelength obviously increased with obvious red shift after complexation. Remarkable increase of fluorescence(19 times), the emission wavelength redshift 18 nm. Fluorescent quantity yield increased from 0.009% to 0.17%.Compound 3c can form 1:1 ratio of ligand complex with Sn2+. After complexation ultraviolet absorption wavelength obviously increased. Remarkable increase of fluorescence(40 times), the emission wavelength redshift 18 nm. Fluorescent quantity yield increased from 0.13% to 5.2%.The results show that nitrogen groups through the appropriate length of linkers and coumarin are linked together,they may be formed by a specific complex cavity.Then chelate with metal ions through the empty cavity of nitrogen and oxygen.The specific radius is used to identify the specificity of the metal ions. The effect for the future coumarin fluorescent probe provides a train of thought and method of structure designation. The synthesis of 3c which identified Sn2+ fluorescent probes will have great significance in the field of medicine in the future.