ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY http://dx.doi.org/10.14233/ajchem.2015.18712 INTRODUCTION 3-Acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one, com- monly referred to as dehydroacetic acid, has continued to receive considerable attention due to the ease with which it reacts with amino compounds and hydrazines to form deriva- tives with interesting coordination chemistry, pharmaceutical importance and high biologically activity 1-5 . Dehydroacetic acid itself is well known for its fungicidal 6 , herbicidal and antimicrobial activities 4 . It is also widely used in food tech- nology, as vitamin C stabilizer and as a preservative in food products like fish sausages 7 . A number of Schiff base deriva- tives of 3-acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one and their metal complexes have been reported 8-15 . The interest in Schiff bases is due to the fact they are superior reagents in biological, inorganic and analytical applications 16-20 . It has also been documented that upon coordination the antimicrobial properties of Schiff bases could be enhanced 21-25 or dimi- nished 26 . Literature search revealed that no work has been done on 3-acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one Schiff base with 2,2'-(ethylenedioxy)diethyl-amine and its metal complexes. In continuation of our series 27-29 on Schiff bases and their metal complexes, we report the coordination chemistry Synthesis, Characterization and Antimicrobial Activity of 3-Acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one Schiff Base with 2,2'-(Ethylenedioxy)diethylamine and its Co(II), Ni(II) and Cu(II) Complexes JONNIE N. ASEGBELOYIN 1,* , IIKNUR BABAHAN 2 , NWANNEKA N. UKWUEZE 1 , UCHECHUKWU S. ORUMA 1 , ESIN COBAN POYRAZOGLU 3 , UCHENNA F. EZE 1 and HALIL BIYIK 3 1 Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka 410001, Enugu State, Nigeria 2 Department of Chemistry, Adnan Menderes University, 09010 Aydin, Turkey 3 Department of Biology, Adnan Menderes University, 09010 Aydin, Turkey *Corresponding author: E-mail: niyi.asegbeloyin@unn.edu.ng Received: 8 September 2014; Accepted: 2 March 2015; Published online: 26 May 2015; AJC-17253 A Schiff base was synthesized by the interaction of 3-acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one with 2,2'-(ethylenedioxy)diethyl- amine in ethanolic medium. The ligand was characterized on the basis of elemental analysis, infrared, 1 H and 13 C NMR spectra. Cobalt(II), Ni(II) and Cu(II) complexes of the type ML(H2O)2 were prepared by interaction of the metal(II) halides with hot ethanolic solution of the Schiff base. The complexes were characterized by elemental analysis, molar conductance, magnetic measurements, infrared and electronic spectral studies. Results show that the ligand behaved as dibasic tetradentate molecule, coordinating via imino nitrogens and the enolic oxygens, to form six-coordinate octahedral metal complexes. The compounds were screened for in vitro antimicrobial activity against some bacteria and yeasts. Results showed that some of the compounds are active against few microbes. Keywords: Pyran-2-one, 2,2'-(Ethylenedioxy)diethylamine, Complexes, Antimicrobial. Asian Journal of Chemistry; Vol. 27, No. 9 (2015), 3345-3349 and antimicrobial study of Schiff base derived from 3-acetyl- 4-hydroxy-6-methyl-(2H)pyran-2-one and 2,2'-(ethylene- dioxy)-diethyl-amine with its Co(II), Ni(II), Zn(II) and Cu(II) complexes. EXPERIMENTAL All the solvents are of analytical grade and were used without further purification. 3-Acetyl-4-hydroxy-6-methyl- (2H)pyran-2-one and 2,2'-(ethylenedioxy)diethylamine were used as supplied by Fluka. Elemental analyses of C, H and N were performed by using Carlo Erba Elemental analyzer EA 1108. Melting point were taken in open capillaries on a melting point apparatus Electrothermal 9100. Magnetic moments were done on a magnetic susceptibility balance–Sherwood Scientific Cambridge, Model No. MK-I. The molar conductance of the complexes was measured using Innolab conductivity meter Level 1. The percentage of metal in the complexes were determined using an Agilent ICP-MS7500Ce. IR spectra were recorded on a Perkin Elmer Spectrum 100. 1 H and 13 C NMR spectra were obtained from a Bruker AV 500 MHZ for 1 H and 125 MHZ for 13 C using a 5 mm Quadra Nuclei Probe (QNP).