Synthesis And Molecule Recognition Of Naphthyridine Nitrogen Heterocyclic Derivatives

The three nitrogen atoms of2,6-diaminopyridine each with a lone pair electrons, the special structure has strong hydrogen bond coordination ability, which makes2,6-diaminpyidine and its derivatives are widely used in various kinds of molecular recognitions.2,6-diaminopydine derivatives can form mono-or multi-dentate ligands with metal ions respectively. Particularly, the2-methyl-7-amino-1,8-naphthyridine derivatives of2,6-diaminopyridine, can special match with G bases through hydrogen bonding interaction, which has the identification function of specific nucleic acid. Therefore the modified2,6-diaminopyridine derivatives have potential application value in molecular recognition. Based on our preliminary work, the electrochemical methods based on naphthyridine derivative were further studied for detection of special nucleotide acids such as GG mismatch duplex, trinucleotide repeats. On the other hand, a series of2,6-diaminopyridine derivatives were synthesized and the interaction of metal ions were investigated by UV-vis spectrophotometry.The main contents of this thesis are summarized as follow:(1) The detection of mismatch duplex electrochemically was further investigated based on the new bifunctional electrochemical probe FeNC. FeNC contains electroactive ferrocene parts and naphthyridine derivatives, which makes FeNC has not only good electrical activity but also specificity ability to nucleic acids. The GG-mismatch duplexes were immobilized onto the surface of bare gold electrode through thiol self-assembly. The GG-mismatch onto the surface of Au electrode can capture the free FeNC, which results in obvious electrochemical signal of FeNC. The studies indicated that FeNC has the selective interaction to GG-mismatch duplex.(2) Amino terminal naphthyridine derivative with long flexible chain, NC-linker was successfully synthesized. A new electrochemical impedance biosensor was built set up by immobilizing the NC-linker onto the surface of bare gold electrode through the condensation of acidcarboxyl acid and the terminal amine. Here, XGG repeats (X=C, T) aqueous solution could be selectively detected based on the differences in charge transfer resistance (ΔRct) even in the presence of other trinucleotide repeats. The relationship between ΔRct and lg[concentration of CGG10repeats] for the sensor was linear from1nM to1μM, enabling the quantification of the number of repeats. The electrochemical impedance sensor provides the simple and rapid method to detect trinucleotide repeats without requiring labelling and immobilizations of DNA. The results make it promising for the early diagnosis of the neurodegenerative diseases; the sensor may be further extended to the detection of other special sequence of DNA.(3) A series of2,6-diaminopyridine derivatives were successful synthesized. The interactions to various metal ions were studied by UV-vis absorption spectra.The results indicated that the derivatives DPAD1and DPAD2can selectively recognize Cu2+with producing new ultraviolet absorption peak, and with1:1binding ration.(4) A series ferrocene derivatives FeL1, FeL2, FeL3, FeL4were synthesized. The basic electrochemical characteristic of the derivatives were studied by electrochemical cycle voltammetry curves, and the basic electrochemical parameters Do, Ks were caculated. The results indicated that the redox processes of the ferrocene derivatives on the electrode surface were controlled by the diffusion of the reversible electrochemical system. On the other hand, the interaction to various metal ions was studied by UV-vis absorption spectra. The studies indicated that the derivatives FeLl and FeL2can obviously recognize Cu2+and weak interaction with Cr3+, and FeL3and FeL4had obvious selectively interaction with Cr3+. Additionaly, the UV-vis and electrochemical results both indicated that FeL3and FeL4can interacted with Cr3+with the1:1binding ratio. This2,6-diaminopyridine derivatives and the interaction of various metal ions provided potential applications to molecular recognition, which has certain research significance.