Synthesis, Characterization And Bioactivities Of New Transition Metal Complexes Of Heterocyclic Sulfur-containing Schiff Base

The wide variety of biological activity was exhibited by heterocyclic thiosemicarbazaones .In the recent research, more attention was paid to the Schiff bases and their metal complexes for their significant antibacterial and antitumor activity. Previous studies have centred mainly on transition metal complexes of sulfur-containing Schiff bases with pyridine or furan series. However the complexes of sulfur-containing Schiff bases with pyrazine or thiazole series were seldom reported. Our main job was described as below;l.Synthesis and Characterization of New Transition Metal Complexes with Schiff base ligands derived from S-benzyldithiocarbazate and 2-acetylpyrazine.New bis-chelated Zinc(II), Manganese(II) and mono- chelated Copper(II) complexes with Schiff base ligands derived from S-benzyldithiocarbazate and 2-acetylpyrazine were prepared. The compounds were characterized by elementary analysis, Mass spectrum,IR Spectra, Electronic Spectra, 1H NMR Spectra and Molar conductance measurements.And their composition and probably structure are confirmed.2. Synthesis and Characterization of New Schiff base ligands derived from S-benzyldithiocarbazate, thiosemicarbazone and 2-acetylthiazole.Two kinds of Schiff bases derived from S-benzyldithiocarbazate, thiosemicarbazone and 2-acetylthiazole were prepared. The compounds were characterized by elementary analysis, IR Spectra, Mass spectrum, 1H NMR, 13C NMR Spectra and their composition and probably structure are confirmed.3. The antibacterial activity of New Transition Metal Complexes with Schiff base ligands derived from S-benzyldithiocarbazate and 2-acetylpyrazine.The antibacterial activity of Schiff base ligands derived from S-benzyldithiocarbazate and 2-acetylpyrazine and their bis-chelated Zinc(II) , Manganese(II) and mon- chelated Copper(II) complexes have been tested against gram-positive bacterium (Staphylococcus aureus, Bacillus thuringiensis, Bacillus megateriumand Bacillus subitilis) and gram-negative bacterium(Escherichia coli, Pseudomomas aeruginosa and Pseudomomas putida). The antibacterial activity results are as follows:(1) the ligands and complexes are differently effective against gram-positive bacterium and gram-negative bacterium.(2) The antibacterial activity of the complexes is stronger than the ligands.(3) The antibacterial activity isn't stronger when the concentration of the compound becames larger,but have the best effect in a certain range. 4. Screening of anti-pyricularia oryzae activity of the complexes that had been prepared.To seek forerunner antitumor drugs from compounds that had been prepared, the screening model of pyricularia oryzae was applied.The anti- pyricularia oryzae activity results showed that the compounds are differently effective against pyricularia oryzae ,and that activity of Schiff bases derived from S-benzyldithiocarbazate and 2-acetylthiazolc are strongest.