Preparation, characterization, biological activity and 3D molecular modeling of Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Ru(III) complexes of some sulfadrug schiff bases

Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Ru(III) complexes of Schiff bases derived from the condensation of sulfaguanidine with 2,4-dihydroxy benzaldehyde (HL1), 2-hydroxy-1-naphthaldehyde (HL2) and salicylaldehyde (HL3) have been synthesized. The structures of the prepared metal complexes were proposed based on elemental analysis, molar conductance, thermal analysis (TGA, DSC and DTG), magnetic susceptibility measurements and spectroscopic techniques (IR, UV-Vis, and ESR). In all complexes, the ligand bonds to the metal ion through the azomethine nitrogen and α-hydroxy oxygen atoms. The structures of Pd(II) complex 8 and Ru(III) complex 9 were found to be polynuclear. Two kinds of stereochemical geometries; distorted tetrahedral and distorted square pyramidal, have been realized for the Cu(II) complexes based on the results of UV-Vis, magnetic susceptibility and ESR spectra whereas octahedral geometry was predicted for Co(II), Mn(II) and Ru(III) complexes. Ni(II) complexes were predicted to be square planar and tetrahedral and Pd(II) complexes were found to be square planar. The antimicrobial activity of the ligands and their metal complexes was also investigated against the gram-positive bacteria Staphylococcus aures and Bacillus subtilis and gram-negative bacteria, Escherichia coli and Pesudomonas aeruginosa, by using the agar dilution method. Chloramphenicol was used as standard compound. The obtained data revealed that the metal complexes are more or less, active than the parent ligand and standard. The X-ray crystal structure of HL3 has been also reported. Novel Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Ru(III) complexes of Schiff bases derived from the condensation of sulfaguanidine with 3 different aldehyde have been synthesized. The structures of the prepared metal complexes are proposed based on elemental analysis, molar conductance, thermal analysis (TGA, DSC and DTG), magnetic susceptibility measurements and spectroscopic techniques (IR, UV-Vis, and ESR). To gain a better insight into the molecular structure of the metal complexes, geometric optimization has been performed using MM3 force field implemented in Sigress. The antimicrobial activity of the ligands and a number of their metal complexes against gram-positive and gram-negative bacteria has been investigated. The obtained data revealed that the metal complexes are more or less, active than the parent ligand and standard.