Study On Synthesis Of Fluorescent Chemosensors Based On Acridine And Their Recognition Properties

Chiral generally exist in the process of life. In biologically, most of the important molecules are chirality, such as amino acid, protein, nucleic acid and so on. Chiral compounds plays a key role in life process, without them life is not likely to appear on earth. Chiral recognition not only plays an important role on the study of supermolecular, but also vital to the development of biology, biomedical, material science and so on. Chiral fluorescent sensor can achieve a simple, rapid detection, so design and synthesis of high enantioselectivity chiral fluorescent sensor has great practical significance and application value for us.The chiral "clamp" host molecules, which bridging with nitrogen atom or oxygen atom, have the adjustable size, and can form hydrogen bond with some anions easily. So they cause more researchers to attract much attention. To introduction of a chiral group and fluorophore among these compounds, and use the different of fluorescence response in the recognition process can be effective chiral recognition.In this thesis, a series of novel artificial fluorescence sensors were designed and synthesized, which cantaining acridine as fluorophore and nitrogen or oxygen atoms link together. There binding and sensing properties for the common anions （chiral carboxylates and chiral amino acid anions） were investigated by UV-vis, fluorescence emission,1H NMR spectra and the discriminating mechanism has been studied preliminarily. The thesis is divided into four chapters, and the main contents are as follows:（1） Briefly describes the research progress for chiral anion recognition and fluorescent sensors based on acridine. Then put forward the design idea of this thesis.（2） Three chiral fluorescent chemical sensors L-1, D-1 and L-2 were synthesized which used acridine as fluorophore. Then studied their selectively recognition ability for chiral anions by fluorescence spectrum and 1H NMR spectra. Sensors L-1 and L-2 were found to present good fluorescence sensing D-malic acid anion, but less efficiency recognition ability to L-malic acid anion. By Job curve between host and guest indicated that they are formed 1:1 complex. The difference of fluorescent response between sensors L-1, D-1 and malic acid anionic showed that they have good enantioselectivity to malic acid anion. Finally, we proposed possible bonding mode between sensor L-1 and malic acid anion by 1H NMR titration experiment.（3） The sensors L-1 and D-1 based on acridine and alkamine have been synthesized and demonstrated. The sensing ability of the compounds in the presence of metal cations was studied by UV-vis, fluorescence spectra, mass spectrum and quantum chemistry calculation. The experimental results indicate that the sensor L-1 could act as selective fluorescent sensor for the Cu²⁺ ion with fluorescence quenching in aqueous solution. Then by mass spectrum and Job curve of host and guest indicated that they are formed 1:1 complex. Additionally, the emission properties of the L-1-Cu²⁺ and D-1-Cu²⁺ complex can be applied as new fluorescent chemical sensor and then studied the sensing ability to the chiral carboxyliate anion. The results showed that sensor L-1-Cu²⁺ have good enantioselective recognition to the phenylalanine anions in aqueous solution.（4） Three chiral fluorescent chemical sensors L-1, D-1 and L-2 have been synthesized based on acridine and a-hydroxy carboxylic acid. Their selectively recognition ability for chiral anionic by UV-vis and fluorescence spectrum were studied. Sensor D-1 was found to present good fluorescence sensing L-tartaric acid anion, but less to D-tartaric acid anion, and L-1 formed the 1:1 complex with tartaric acid anion. The difference of fluorescent response between sensors L-1, D-1 showed that they have good enantioselectivity to tartaric acid anion.