Spectronic Properties And Nucleic Acid-binding Mechanism Studies Of Ruthenium(Ⅱ) Polypyridyl Complexes

Nucleic acid is the overall name for DNA and RNA. DNA is also known as"genetic particle", as genetic material of cells it contains all the genetic information todetermine the properties and characteristics of materials. Nucleic acids alloworganisms to transfer genetic information from one generation to the next. there aremainly three kinds of different RNA, they are ribosomal RNA （rRNA）, transfer RNA（tRNA）, and messenger RNA （mRNA）. Each type of RNA has a different role invarious cellular processes but they perform cooperative functions in protein synthesis.Ruthenium complexes usually used to interact with nucleic acids and sdutied byresearchers due to their thermal stability, chiral octahedral geometry, richphotophysical and photochemical information. This thesis includes five chapters.In the first chapter, We introduced the composition and structure of nucleic acidsas well as the research methods and the application of the interaction betweenruthenium complexes and nucleic acids.In chapter two, Novel complexes [Ru（dppz）₂phen]²⁺and [Ru（dppz）₂dpq]²⁺,which contain two intercalative ligands were designed and synthesized. Aftercharacterization, the interaction between the complexes and DNA was studied byspectroscopic method and viscosity measurement. The results show that bothcomplexes combined with DNA through intercalative mode; the size and number ofintercalative ligand has a great influence on binding strength. In addition, bothcomplexes showed antitumor activities against selected tumor cell lines, and can makethe cells apoptosis.In chapter three, a new ruthenium porphyrin complexRu（phen）₂TCPBA-ATPPH2was designed and synthesized. The interaction ofcomplex and three kinds of nucleic acids （CT-DNA, poly （rA） poly （rU）, poly （rU））were studied by spectroscopic and fluid mechanics methods. Data show that thecomplex combined with DNA through intercalation mode, with poly （rA） poly （rU）by groove binding mode and with poly（rU） by simple external binding mode. Itindicates the complexe can recognize different structure of nucleic acids and bindwith them by different modes. When added CT-DNA, Ni²⁺and EDTA successively,the emission intensity of Ru（phen）₂TCPBA-ATPPH2showed “on-off-on” effect.In chapter four, Designed and synthesised new ruthenium complex Ru （phen）₂TCPBA which contains imidazole ring with a carboxyl group on it. Thecomplex was characterized by NMR and mass spectrometry. The interaction of thecomplex with four different nucleic acids （DNA, single-strand RNA, duplex RNA,triplex RNA） were studied by absorption spectra and steady state emission spectra.The results showed the complex binds with DNA by intercalation mode. But whentitrated with the other three kinds of nucleic acids, both the electronic absorptionspectra and fluorescence spectra showed almost no changes, indicating the complexselectively binds with DNA. In acid-base titration test both electronic absorptionspectra and fluorescence spectra showed three stages distinguished in term ofabsorbance and fluorescence intensity, indicating the complex has the potential for pHsensor.In chapter five, Synthesized and characterised two ruthenium complexes[Ru（dppz）₂（tbtc）]²⁺,[Ru（dppz）₃]²⁺and investigated their DNA-binding propertiesereby luminescence titration, UV-Vis and viscosity measurements. The results show thatboth complexes bind to DNA by intercalative mode. However, due to the sterichindrance of ester group （-COOCH3） on tbtc, DNA-binding affinity of[Ru（dppz）₂（tbtc）]²⁺is lower than that of [Ru（dppz）₃]²⁺. In addition, the complexesshowed different in vitro antitumor activities against two tumor cell lines and madethe cells apoptosised.