SYNTHESIS, STRUCTURAL ELUCIDATION AND ANTIMICROBIAL ACTIVITIES OF SOME MACROCYCLIC COMPLEXES OF Ni(II) HAVING N2S2 POTENTIAL DONORS IN 18-24 MEMBERED RINGS.

Macrocyclic complexes of Ni(II) having N2S2 potential donors in 18-24 membered rings, of the general formula: Ni(L1-5)X2, Where X=Cl-,CH3COO-,NO3 - and L(1-5) is Macrocyclic ligands have been synthesized from the reaction of Nickel(II) salt, Dicarboxylic acids and p-aminothiophenol in 1:2:2 moler ratio in methanol. These complexes have been characterized by elemental analysis, molar conductance, molecular weight determination, IR spectra, reflectance spectra, thermo gravimetric analysis and magnetic measurements. Molecular weight determination of these complexes indicates their monomeric nature. Octahedral structure has been proposed on the basis of Spectrul data, magnetic data, Reflectance spectra, and Magnetic measurements. Two sulphur atoms and two nitrogen atoms of the macrocyclic ring coordinate to the central nickel ion in the square planar form in unidentate behavior. Antimicrobial activities of these complexes have been studied by screening them against fungi, such as Aspergillus flavus, Fusarium oxysporum, Trichoderma harzianum, and bacteria, such as Salmonella typhi and Bacillus subtili. Thise macrocyclic complexes were found to be more fungitoxic and antibacterial than bavestin and streptomycin taking as a standered.