IOSR Journal of Applied Chemistry (IOSR-JAC) e-ISSN: 2278-5736. Volume 5, Issue 2 (Jul. – Aug. 2013), PP 36-39 www.iosrjournals.org www.iosrjournals.org 36 | Page Antibacterial Application of Novel Mixed-Ligand Dithiocarbamate Complexes of Nickel (II) Anthony Chinonso Ekennia Department of Chemistry, University of Ibadan, Ibadan. Nigeria. Abstract: Nine stable mixed ligand dithiocarbamate complexes of Nickel (II) ion were prepared. The complexes were characterized with electronic spectroscopy, infrared spectroscopy, conductance measurement, melting point and percentage metal analysis. Resulting analytical data gave credence to the assignment of a tentative square planar geometry to all the complexes. The complexes were proposed to have a general formulae of [Ni(Sal)(Rdtc)], where Sal = salicylaldehyde; R = dibenzylamine(Bz 2 NH), methylphenylamine(MePhNH),pyrrolidineamine(pyrrolNH),piperidineamine(piperNH),morpholineamine(Morp NH), anilineamine(AnilNH), para-chloroanilineamine(p-ClAnilNH), toludineamine(TolNH) and anisidineamine(AnisNH); and dtc = dithiocarbamate anion. The metal complexes were screened against six different bacteria strain using Agar diffusion method. The antibacterial studies reveal that the metal complexes exhibit broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella oxytoca and Pseudomonas aureginosa with inhibitory range of 10.5. —20.0mm. Keywords: Aromatic dithiocarbamate, Salicylaldehyde, Antibacterial studies and Nickel ion. I. Introduction Dithiocarbamates are versatile compounds with wide range of chemistry. An extremely large number of dithiocarbamate complexes with transition and non transition metal ions have been reported (Dawood et al.2009; Daniel et al.2009 and Sarwar et al.2007). Compounds with dithiocarbamate moiety have attracted attention because of their potential biological activity (Leka et al. 2006). Their metal complexes present striking structural features and have diversified applications, such as high pressure lubricants, fungicides, pesticides, and accelerators used in vulcanization (Beer et al.2001). There has been growing interest in the formation of mixed ligands chelates involving ligands containing different functional groups and transition metals of different oxidation states (Samus et al 2006 and Manov et al.2004). Coordination compounds with mixed ligands are of considerable importance in the field of metalloenzymes and are known to possess various biological activities (Rai et al.2005). Hence a large number of mixed ligand complexes with various transition metals are known (Mahapatra et al.1986 and Rai et al.2006). As a continuation of our research on mixed ligand complexes of dithiocarbamate moiety with salicylaldehyde ( Ekennia and Odola, 2013), we report herein, the synthesis, characterization and antibacterial application of nine mixed ligand complexes of aryl dithiocarbamate and salicylaldehyde moiety with the aim of producing lead compounds for the production of effective and more selective bactericides. II. Experimentation 2.1 Reagents Hydrated nickel(II) chloride, carbon disulfide, sodium hydroxide, dibenzylamine, methylphenylamine, pyrrolidineamine, piperidineamine, morpholineamine, anilineamine, para-chloroanilineamine, toludineamine and anisidineamine were bought from Aldrich and Sigma Co. and British Drug House and used as supplied. 2.2 General Preparation of mixed ligand complexes The complexes were prepared according to literature (Ekennia and Odola, 2013). Equimolar concentration of the dithiocarbamate, metal ion and salicylaldehyde moiety was added to an ethanolic solution and refluxed for 3 hours. The resulting precipitate was filtered under vacuum, washed with diethylether and stored under silica gel in desiccator.