Syntheses, Photochemistry Of Nickel Diimine-based Complexes And Their Interactions With DNA

As the most terrible disease of the world civilization, cancer caused the death of7million people every year. Because cancer is difficult to cure, and is endangering the people's life, it has become the main target in the medicinal area. With the development of science and technology, cancer therapy skills, such as surgical therapy, radiation therapy and anticancer chemical therapy, have been greatly improved in recent years. But these therapeutic skills still cannot meet people's demands. Now people are striving to find a new method for curing cancer. Photodynamic therapy(PDT) is a new and effective method of cancer therapy.PDT is a recently developed therapeutic modality for cancer diagnosis and treatment of various types of tumor by irradiating the photosensitizer with red light to produce reactive oxygen species in targeted cells. Thus the choice of the photosensitizer is essential for the cancer diagnosis and treatment. Different photosensitizer would have different effect, searching more efficient photosensitizers which can generate reactive oxygen species is therefor getting our main target. The structure of the photosensitizer could been modified by introducing various substituents to get more appropriate photosensitizer to generate reactive oxygen species in red light.Three metal complexes have been synthesized, and structures have been characterized by many ways. Interactions of these metal complexes with DNA have also been investigated. The major work has been summed up as follows:(1)4-Bromo-N,N-diphenylaniline and4-triphenylamine-phenylenediam-ine were synthesized and identified by elemental analysis, IR and1HNMR spectra.(2) Ni(OPDA)(4-Br-OPDA), Ni(OPDA)(TPA-OPDA) and Pt(OPDA)(4-Br-OPDA) were synthesized and identified by elemental analysis, IR, UV and HNMR spectra.(3) With DPBF as a probe, the singlet-oxygen-generating ability of these metal complexes have been studied by fluorescence spectra. These complexes include Ni(OPDA)2, Ni(OPDA)(4-Br-OPDA), Ni(OPDA)(TPA-OPDA) and Pt(OPDA)(4-Br-OPDA). The results showed that Ni(OPDA)(TPA-OPDA) and Pt(OPDA)(4-Br-OPDA) can efficiently produce singlet oxygen when irradiated with red light.(4) The binding modes between Ni(OPDA)(4-Br-OPDA), Ni(OPDA)(TPA-OPDA) and Pt(OPDA)(4-Br-OPDA) with DNA have been studied by UV-Vis spectra, fluorescence spectra and viscosity measurements. The results show that these complexes might bind to DNA by intercalation.(5) By gel electrophoresis technique, the interactions of metal complexes, Ni(OPDA)(TPA-OPDA) and Pt(OPDA)(4-Br-OPDA), with plasmid pBR322DNA have also been studied. The results show that upon irradiation at λ>630nm, these complexes may all lead to the cleavage of plasmid pBR322DNA. Compared to Ni(OPDA)(TPA-OPDA), Pt(OPDA)(4-Br-OPDA) is relatively more efficient. The two complexes may have the same mechanisms to cleavage DNA, and the cleavage DNA could been attribute to production of singlet oxygen.