Synthesis, Structural Characterization And Biological Activity Of N-benzoyl-N′-arylthiourea Derivatives And Their Complexes With Some Metals

N-benzoyl-N′-arylthiourea derivatives and their metal complexes have increasingattention for a long time due to their important application of biological activities,such as antivial, anticancer, antibacterial, etc. N-benzoylthiourea derivatives alsocould be used in the extraction and sepration of platinum metal group based on theirgood chelating ability.In this thesis, three kinds of metal complexes of N-benzoyl-N′-arylthioureaderivatives have been synthesized. Elemental analysis, IR, UV spectra, fluorescencespectra, cyclic voltammogram and nuclear magnetic resonance spectra wereperformed to confirm the formation and characterization of these complexes. Theantibacterial activities of complexes and their interaction with calf thymus DNA werestudied. The main contents of the thesis are given as follows:Chapter I: The synthetic methods and the application of thiourea derivatives,acylthiourea derivatives and their metal complexes were reviewed. The test methodand mechanism of interaction between DNA and complexes were summarized. Theapplication status of benzoylthiourea derivatives in chemistry and molecular biologywere literatured.Chapter II: Four kinds of novel copper complexes of N′-substitutedbenzoylthioureas have been synthesized via the reaction of N-benzoyl-N′-arylthioureawith CuCl2in ethanol solution. Elemental analysis, IR, UV spectra, fluorescencespectra and cyclic voltammogram were performed to confirm the formation andcharacterization of these complexes. The results indicate that the N′-substitutedbenzoylthiourea ligands are coordinated to the Cu2+through the sulphur atom in aterminal mode to form the cis-or trans-[Cu(L-S)2Cl2] complexes.Chapter III: After the reaction of PdCl2and KCl in H2O to yield K2PdCl4, aseries of complexes of N-benzoyl-N′-arylthiourea with palladium have beensynthesized using the reaction of K2PdCl4and N-benzoyl-N′-arylthiourea inacetonitrile/water solutions. The characterization and the formation of the palladiumcomplexes were studied by elemental analysis, UV-VIS, FT-IR, fluorescence spectraand1HNMR. The results show that all of the N-benzoylthiourea derivatives are coordinated to the Pt2+through the sulphur and oxygen atom to yielding thecis-[Pd(L-O,S)2] complexes.Chapter IV: A family of platinum complexes of N′-substitutedbenzoylthioureas have been prepared by the reaction of N-benzoyl-N′-arylthioureaand K2PtCl4in dioxane/water solutions. They are characterized by elemental analysis,UV-VIS, FT-IR, fluorescence spectra and1HNMR. The results demonstrate that TheN-benzoyl-N′-arylthiourea ligands coordinate to Pt2+in a bidentate manner yieldingessentially neutral complex of the type cis-[Pt(L-O,S)2].Chapter V: The antibacterial properties of the ligands and complexes againstGram-positive bacteria(Staphylococcus aureus and B. Subtilis) and Gram-negativebacteria(E.coli) were investigated. Comparing to the compounds, their correspondingcomplexes have much stronger control for the cover bacteria. Binding interaction ofthe complexes with calf thymus DNA(ct-DNA) has been performed by UV titration,fluorescence, and viscosity measurements. The results of DNA cleavage experimentsof the complexes reveal that all of the complexes can intercalate with ct-DNA indifferent degree, which is in agreement with their DNA binding and cleavagebehaviors. The binding constants(Kb) was calculated via relevant fluorescencequenching data for each complex. The bonding constant of the palladium complexwith N-benzoyl-N′-(3,4-methoxyphenyl) thiourea is the highest. The mechanism ofintercalation and the antimicrobial activity reason of the complexes were discussed.