2017. 58, 2 – UDC 548.73:541.49:546.72/.74 STRUCTURAL DIVERSITIES AND PRELIMINARY ANTIMICROBIAL STUDIES OF 1-((E)-(PENTYLIMINO)METHYL)NAPHTHALEN-2-OL AND ITS METAL COMPLEXES M. Ahmad1, Z. Perveen2, A.J. Bortoluzzi3, S. Hameed4, M.R. Shah5, M. Tariq4,6, G. ud Din2, M. Anwar2 1Medicinal Botanic Centre PCSIR Labs Complex University Road Peshawar-25120, Pakistan E-mail: mushtaqpcsir@yahoo.com 2Institute of Chemical Sciences University of Peshawar, Peshawar-25120, Pakistan 3Departmento de Quнmica, Universidade Federal de Santa Catarina, Florianopolis, Brazil E-mail: adailton.bortoluzzi@ufsc.br 4Deparment of Chemistry, Quaid-I-Azam University, Islamabad-45320, Pakistan 5HEJ Research Institute of Chemistry University of Karachi, Karachi-75270, Pakistan 6Department of Chemistry Shaheed Benazir University, Sheringal-18050, Pakistan Received August, 7, 2015 Revised — September, 5, 2015 Schiff bases and their metal complexes have a number of biological activities such as antidepressant, analgesic, antimicrobial, antiviral, and antitumor. <...> In the present studies, the 1-((E)(pentylimino)methyl)naphthalen-2-ol ligand is prepared by the reaction of 2-hydroxynaphthaldehyde with n-amyl amine. <...> The ligand results in CoL3, NiL2 and CuL2 complexes when reacted with the cobalt acetate, nickel acetate, and copper acetate salts respectively. <...> The complexes along with their ligand are fully characterized by X-ray diffraction studies and biologically screened. <...> The ligand structure reveals that it is a zwitterion species where the iminic nitrogen atom is protonated and the C—O bond shows a high double bond character. <...> The cobalt complex has an octahedral geometry around the metal center and each nitrogen atom is in the trans position to the oxygen donor site. <...> On the other hand, the copper complex shows a centrosymmetric square planar coordination, and in this case, the nitrogen sites are trans to each other. <...> The complexes and the ligand are found to be more potent than the standard drugs used against some microbes in their preliminary biological studies. <...> INTRODUCTION Schiff bases, first prepared by Hugo Schiff in 1864 [ 1 ], are one of the most important classes of organic compounds. <...> They contain the azomethine (C=N) functional group and are also known as imines. <...> Schiff bases have a number of biological activities <...>