First approach towards some novel macrocyclic complexes having mixed ligands : synthesis, characterization, catalytic and antimicrobial aspects of some nickel(II) macrocyclic complexes having tetraoxotetrathiotetraaza ligands in 24-28 membered rings

Department of Chemistry, Hemchandracharya North Gujarat University, Patan-384 265, India E-mail: cpbhasin@yahoo.com Manuscript received 22 September 2004 Alkylene dithiophosphate derivatives of macrocyclic complexes of nickel(ll), having potential donors N4S4 of the general formula, [Ni(L){S2P\(\langle\)\( \begin{array}{c} O \\ O \end{array} \)\(\rangle\)G}2](where L = macrocyclic ligands L1, L2 and L3 and G = CH3-CH-CH-CH3, (CH3)2.C-C.(CH3)2, (CH3)2C-CH2-CH-, CH2-C(CH3) 2-CH2 and CH2-C(C2H5)2-CH2 have been synthesized from the reactions of [Ni(L)X2] (where X = Cl, NO3 or CH3COO) with ammonium alkylene dithiophsphates in 1 : 2 molar ratios in THF. These complexes have been characterized by elemental analysis, molar conductance, molecular weight determinations, IR, 31P NMR, electronic spectra and magnetic measurements. Molecular weight determinations of these complexes indicates their monomeric nature. Octahedral structures have been proposed on the basis of 31p NMR, electronic spectra and magnetic measurements in which four nitrogen atoms of the macrocyclic ring coordinate to the central nickel ion in square-planar geometry and each dithiophosphate moiety occupies the axial positions binding the central nickel ion in a unidentate manner. Out of twenty one newly synthesized complexes, ten were tested for their catalytic activity, and all the ten complexes were found to be effective catalyst for the oxidation of thiol and benzyl alcohol. The anti-microbial activities of these derivatives have been studied by screening them against fungi like Aspergillus flavus, Fusarium oxysporum, Trichoderma harzianum and bacteria like S. typhi and B. subtili. The alkylene dithiophosphate derivatives were found to be more fungitoxic and antibacterial then their corresponding macrocyclic complexes