Coordination Reaction Of Sulfonamides Ligand And Copper(Ⅱ) Or Iron(Ⅲ) In Condition Of Hydrothermal

Sulfonamides as the effective antibacterial agents are to be employed to the prevention and cure of local and general bacterial inflections. The researches on sulfonamides metal complexes have attracted much attention due to the fact that the antibacterial activities of sulfonamides are enhanced by coordination with metal ions.In this paper, treatment of sulfamonomethoxine or sulfathiazole with Cu(CH₃COO)₂·H₂O(II) in condition of hydrothermal, the corresponding metal complexes were produced respectively. The compounds were characterized by elemental analysis, IR, UV-Vis and X-ray single crystal diffraction. The results showed that two compounds are binuclear; each copper ion is coordinated by two N atoms from sulfonamide and heterocycle, exhibiting the linear geometry. The compounds were calculated by Density Functional Theory (DFT) method. The calculation indicated that the copper ions in complexes are one positive valence in agreement with crystal structure and spectrum. The Mulliken population analysis has a good testimony for the coordination in the crystal structures. Orbital density isosurface analysis speculated that the compounds have high antibacterial activity.Treatment of sulfametopyrazine with FeCl₃·6H₂O(III) in condition of hydrothermal, the corresponding metal complexes were produced. X-ray single crystal diffraction analysis showed that iron ion is coordinated by four oxygen atoms linked pyrazine ring and two oxygen atoms from sulfate radical and the complex exhibits torsion octahedral geometry. In the course of hydrothermal synthesis, cleavage and chosen oxidation occured on sulfametopyrazine ligand molecular. Cleavage sites were inferred by bond degradation energy calculation using DFT method. The calculation also indicated that the iron ion in complex is two positive valences in agreement with crystal structure. The Mulliken population analysis has a good testimony for the coordination in the crystal structure.In addition, the discussion on metal valence change in the course of hydrothermal reaction showed that it is a universal phenomenon that high valence metal is reduced to low valence or mixed valence in condition of hydrothermal. Organo N that embodies containing N heterocyclic ring and pyridine family or ammonia water is main reductions in the change of metal valence. High temperature (100～1000℃) and high pressure (10～100MPa) in condition of hydrothermal are in favor of reduction of transiton metal.