Synthesis, Characterization And Properties Investigation Of The Transition Metal Complexes With Nitrogen Heterocyclic Schiff Base Ligands

In this paper, thirteen Schiff base ligands and three reductive Schiff base ligands bearing nitrogen heterocyclic units, including twenty transition metal complexes with nine ligands have been synthesized. In addition, the biological activities of some compounds have been investigated. A series of significant conclusions have been achieved from such results.The dissertation includes following five chapters:1. It was given a brief review of the research progress of the complexes with Schiff base ligands including the Schiff base ligands bearing pyrrole units.2. In this chapter, the ligand H₂L¹ and its Zn(â…¡),Cu(â…¡) and Ni(â…¡) complexes were synthesized and fully characterized. The DNA binding properties of the ligand H₂L¹ and the complex NiL¹Â·3H₂O were also investigated. The complex NiL¹Â·3H₂O can bind to DNA and has potential pharmaceutical activity. In addition, the varieties of the fluorescence emission was obtained in the presence of several metal ions in THF solution of the ligand, the results indicate that H₂L¹ may be a potential fluorescent sensor for Zn²⁺.A ligand was involved in this chapter:H₂L¹:1,7-di(1 -phenyl-3-methyl-5-pyrazolone-4-benzylidene)-diethylenetriamine3. Four bis(pyrrol-2-yl-methyleneamine) ligands H₂L^2-5 and their Zn(â…¡), Cu(â…¡) complexes were synthesized and characterized, the crystal structures show that each complex of ligands H₂L^2,5 possesses a double-stranded helical geometry. The DNA binding experiments indicate that [ZnL²]₂, H₂L⁵ and [ZnL⁵]₂ can bind to DNA via different modes and all of them have potential pharmaceutical activities. The Superoxide radical scavenging experiments show that the Cu(â…¡) complexes display simlilar superoxide dismutase activity compared with that of native Cu,Zn-SOD and may be potential SOD substitutes. Furthermore, the varieties of the fluorescence emission was obtained in the presence of several metal ions in CH3CN solution of the ligands, the results indicate that H₂L^2-4 may be potential fluorescent sensors for Zn²⁺.Four ligands were involved in this chapter: H₂L²: 1,2-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methyleneamino]ethaneH₂L³:1,3-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methyleneamino] propaneH₂L⁴:1,6-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methyleneamino]hexaneH₂L⁵:1,2-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methyleneamino] benzene4. Three bis(pyrrol-2-yl-methylamine) ligands H₂L^6-8 and their Zn(â…¡), Cu(â…¡) complexes were synthesized and characterized in this chapter. The DNA binding experiments indicate that all compounds can bind to DNA and have potential pharmaceutical activities. The Superoxide radical scavenging experiments show that the Cu(â…¡) complexes display simlilar superoxide dismutase activity compared with that of native Cu,Zn-SOD and need further research.Three ligands were involved in this chapter:H₂L⁶: l,2-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methylamino]ethaneH₂L⁷:1,3-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methylamino] propaneH₂L⁸: 1,6-Bis[3,4-dimethyl-5-ethyloxy-carbonyl-pyrrol-2-yl-methylamino]hexane5. Eight Schiff base ligands bearing pyrrole units and the Zn( II), Cu( II) and Ni( II) complexes of HL¹² were synthesized and characterized. The antioxidant activities of HL¹² and its complexes were investigated. The Superoxide radical scavenging experiments show that the Cu(â…¡) complexes display higher superoxide dismutase activity than other complexes, Cu(â…¡) ion plays an active role.Eight ligands were involved in this chapter:L⁹: 3,4-dimethyl-pyrrole-2-carboxylic 2-hydroxybenzylidenehydrazideL¹⁰: 3,4-dimethyl-pyrrole-2-carboxylic furan-2-yl-methylidenehydrazideL¹¹: 3,4-dimethyl-pyrrole-2-carboxylic 2',4'-dihydroxybenzylidenehydrazideHL¹²: 3,4-dimethyI-pyrrole-2-carboxylic (5'-hydroxy-3'-methyl-1'-phenyl-1H-pyrazol-4'-yl)(phenyl)methylidene)hydrazideL¹³: ethyl 3,4-dimethyl-5-((naphthalen-1-ylimino)methyl)- pyrrole-2-carboxylateL¹⁴: ethyl 3,4-dimethyl-5-((naphthalen-2-ylimino)methyl)- pyrrole-2-carboxylateL¹⁵: ethyl 5-((benzoylimino)methyl)-3,4-dimethyl-pyrrole-2-carboxylateL¹⁶: ethyl 5-((isonicotinoylimino)methyl)-3,4-dimethyl-pyrrole-2-carboxylate...