Studies On The Synthesis, Crystal Structure Of Novel Metal Complexes And Their Interactions With DNA

Deoxyribonucleic acid (DNA) is the most important genetic substance in organisms. As the basis of genetic expression, it plays an important role at the process of storing, copying and transmitting gene messages. The investigation of interaction of DNA with other molecules is of great importance in elucidating the structure of DNA and their functions. Bridged polynuclear structures exist widely in the active sites of the metalloprotein and metalloenzyme in organisms that makes a great impact on their physiology and catalysis. Studies pertaining to the functional complex and DNA interaction have utilized for developing novel chemotherapeutic agents, footprinting agents and for gene manipulation in biotechnology and medicine. The design, synthesis of novel functional coordination compounds with antitumor activity remain an elusive scientific challenge in the fields of coordination chemistry and medicinal chemistry.In this thesis, we focused on the design, synthesis of metal complexes with novel structures by successful synthetic strategy of using N,N'-bis(substituent)oxamide as bridged ligand, incorporating other routine ligands, controlling species of metal ions, negative ions in complexes, solvent and changing pH according to the main route of designing and synthesizing bridged polynuclear complexes with novel structures. Furthermore, the influences of solvent and other reaction conditions on preparation, composition, coordination modes and crystal structures of these complexes are discussed. In this thesis, several transitional metal complexes were synthesized and characterized, and the actions of these complexes to DNA were also investigated. This thesis consists of four parts as follows:At first, a summary of the studies on the interaction between the complexes and DNA, and.the synthesis, structure of the complexes bridged by oxamide has been made.In the second part, one new dissymmetrical N,N'-bis(substituent)oxamide N-benzoato-N'-(2-hydroxyethyl)oxamide (H3obzh) and its mononuclear nickel complex Ni(H2obzh)2(en)2, had been synthesized and characterized. DNA binding studies of H3obzh and Ni(H2obzh)2(en)2 with HS-DNA had also been investigated by the spectroscopic and viscosity measurements. In the third part, one dissymmetrical oxamide with no phenyl substituent (H2dpho), had been synthesized and characterized. The first trinuclear copper(II) complex Cu3(dpho)2(MeCN)2(NCS)2 and one novel polymeric copper(II) complex [Cu3(dpho)2(N3)2]n·nTHF bridged by trans-oxamide had been synthesized and characterized by X-ray single crystal diffraction, elemental analysis, IR spectra. They were the first instance of zero-dimensional and one-dimensional trans-oxamide bridging complexes with different ligancies, respectively. The interactions of the two complexes and HS-DNA had been studied by the spectroscopic, electrochemical and viscosity measurements. The results demonstrated that all these compounds can interact with HS-DNA.In the fourth part, three mononuclear complexes [Cu(deta)(phen)](pic)2 (4), [Cu(dmen)2(H2O)2](ox) (5) and [Zn(bpy)3](ClO4)2·H2O (6) had been synthesized and characterized by X-ray single crystal diffraction, elemental analysis, IR spectra, their interactions with HS-DNA have also been studied. The results indicated that complex (4) and complex (6) bind to HS-DNA in an intercalation mode.