Novel Cationic Metal Complexes And Polymer: Synthesis, Characterization And Interaction With DNA

Ruthenium complexes composed by Ru and legends have many excellent characteristics such as good photothermal stability, good solubility, rich redox properties and the rigid octahedral structure and so on. Thus, such complexes have a wide application in many fields, such as organic semiconductor materials, electrochemical luminescence, solar cells and light-emitting devices etc. On the other hand, recently, using cationic conjugated polymers as sensors for DNA have attracted great attention due to several important advantages, such as signal amplification, easy fabrication into devices, and combination of different outputs. Therefore, this thesis aimed to study on the synthesis, characterization and interaction with DNA of several ruthenium complexes and novel poly (pyridinium salt)s.Part I: Three ruthenium bipyridyl complexes were synthesized, which exhibited excellent physical and electrochemical properties. Their photophysical and electrochemical properties of the three complexes were characterized by means of UV-vis, FL spectra and cyclic voltammetric (CV) techniques. The results showed that these complexes have unique MLCT process and stable redox properties. Moreover, we studied the electroluminescent properties of the three complexes. The simple device for each complex was prepared with the structure of ITO/PEDOT-PSS/complex/Al, and pure red light emission was obtained with very low luminescent efficiency. Finally, the interaction of these complexes with calf thymus DNA was investigated by the spectrum titration method. Based on these results, interaction model between the complexes and DNA as well as the influence of complex structure on the interaction were discussed.Part II: Novel poly (pyridinium salt)s were synthesized by stepwise polymerization of the calix[4]arene diamine with the dipyrylium. The features of these poly (pyridinium salt)s are as following: 1) dipyridinium salts units as fluorescent groups. These positively charged poly (pyridinium salt)s has good hydrophilicity, and can interact with negatively charged DNA; 2) calix[4]arene units as recognition site, which can interact with counter ion of Na+ of DNA, while their structural flexibility will facilitate the corresponding polymer to dissolve in various organic solvents and will facilitate polymers to adjust their structure to meet the shape adaptability with the secondary structure of biological macromolecules. Poly (pyridinium salt)s were synthesized and characterized by NMR, FTIR and elemental analyses. Their thermal properties, crystallization and solubility were also characterized. Their optical properties in solution were investigated by UV-vis and photoluminescence spectroscopy. The effct of the experimental factors such as excitation wavelength and the polarity of solvent on fluorescent emission spectra of polymers was studied in detail. Finally, the interaction between the two polymers and DNA are investigated through PL titration and transmission electron microscopy (TEM). It was found that these polymers could contract DNA. The electrostatic interactions of the positively charged polymer with the negatively charged DNA should be one of predominant driving forces.