Study On Syntheses, Physical&Chemical Properties, And DNA Activity Of Novel Coordination Compounds With Planar Structure Ligands

Obeject:To design and synthesize transition metal coordination complex with planar and Schiff Based ligands, then do screening for the potential of new anticancer drugs and magnetic properties.Methods:First, based on previous study, we synthesized planar ligand H3OBP, and further synthesized metal complexes of1and2, then determined their structure by infrared spectroscopy, X-ray diffraction and other methods. The interaction of complexes1and2with DNA was investigated by fluorescence emission spectrometry. Moreover, we prepared two Schiff base ligands Me-BIS and Cl-BIS as well as their coordination compound. By infrared spectroscopy and X-ray diffraction, we determined the structures of ligands and their complexes. Then, we designed and synthesized Schiff base ligand2-((5-chloro-2-hydroxybenzylidene)amino) ethanesulfonate.With co-ligand phenanthroline, we obtained compound with Cu(Ⅱ) and2-((5-chloro-2-hydroxybenzylidene)amino) ethanesulfonate. We also prepared3-((5-chloro-2-hydroxybenzylidene)amino) propanoic acid and its two copper compound. These two compounds were characterized by magnetic measurement and their DNA cleavage property was investigated by agarose gel electrophoresis.Result:We successfully prepared one benzimidazole and4Schiff base ligands as well as their coordination complexes. These compounds were characterized by single-crystal X-ray diffraction. The addition of complex1and2to the DNA bound EB solutions, caused obvious reduction in emission intensities, indicating that complex1and2competitively bound to DNA with EB. The apparent binding constant (Kapp) at room temperature are calculated to be4.31×105M-1for complex1and3.14×105M-1for complex2. Agarose gel electrophoresis experiments indicates that:pUC19DNA can be converted from Form Ⅰ into Form Ⅱ by complex3and4, and with with the increase of the complex concentration, the intensity of the circular supercoiled DNA (Form Ⅰ) band was found decrease, while that of nicked (Form Ⅱ) bands increase apparently. The variable-temperature magnetic susceptibility measurements (2-300K) of3shows the dominant weak ferromagnetic interactions between the chains.Conclusion:1) The DNA cleavage property of complexes1and2are really weak for the metal ion surrounded by ligands. But the DNA binding ability is desirable, probably because the OH group enhances binding capacity with DNA. If we continue to modify this ligand, we may have novel antitumor complexes.2) Bis-Schiff base ligands, which are relatively not suit to form single crystal, need to be meliorated.3)2-((5-chloro-2-hydroxybenzylidene)amino) ethanesulfonate is more likely to coordinate than Bis-Schiff base, but it’s also hard to obtain crystal.4)3-((5-chloro-2-hydroxybenzylidene)amino)propanoic acid is an excellent ligand, the infinite1D coordination polymers of complex3makes it weak ferromagnetic interactions, and both complexes3and4have DNA cleavage property, which indicates that these Schiff based complexes can be designed as antineoplastic compound.