© 2020 JETIR February 2020 , Volume 7, Issue 2 www.jetir.org (ISSN-2349-5162) JETIRDI06057 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 295 Quantum mechanical and pharmacophore analyses of transition metal complexes of N-(5- bromo-2-hydroxyacetophenone)-N’-(2- hydroxyacetophenone)-2,6-diaminopyridine Atish K. Maldhure 1 *, Vijay H. Masand 2 ,Nilima A. Kalambe 3 , Mahendrasingh J. Pawar 1 , Anil R. Somwanshi 4 1 Department of Chemistry, Arts, Commerce and Science College, Kiran Nagar, Amravati, Maharashtra, India 2 Department of Chemistry, VidyaBharati College, Camp, Amravati, Maharashtra, India 3 Department of Chemistry, ShriShivaji Science College, Amravati, MS, India, 4 Department of Chemistry, J. D. PatilSangludkarMahavidyalaya, Daryapur, MS, India. Abstract: Unsymmetrical Schiff Base transition metal (Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ , Cr 2+ and Fe 2+ ) complexes with tetradentate unsymmetrical Schiff base ligand N-(5-bromo-2-hydroxyacetophenone)-N’-(2-hydroxyacetophenone)-2,6-diaminopyridinehas been synthesized by a simple method using DMF as a solvent and alcoholic ammonia to maintained the pH 7.5 -8.00. This ligand has been prepared by condensation reaction between 5-bromo-2-hydroxyacetophenone and o-hydroxyacetophenone with 2,6- diaminopyridine. The ligand and the prepared complexes have shown good to better antimicrobial activity against bacteria Staphalococcusaureus, Bacillus Subtilis, Salmonella typhimurium and Escherichia coli and fungi Aspergillusoryzae and Fusarium species. Furthermore, quantum mechanical and pharmacophore analyses of transition metal complexes and ligand reveals that on coordinating with metal, the pharmacophore pattern as well as the electron density distribution of a metal ligand changes significantly. This could be used for achieving specific type of pharmacophore pattern for deriving novel compounds with desired pharmacophore with targeted activity profile. Keywords: Unsymmetrical Schiff Base, Antimicrobial Activity, Pharmacophore analysis. Introduction: The chemistry of Schiff’s bases, named after Hugo Schiff (Frankfurt, 26 April 1834 -Florence, 8 September 1915), is more than hundred years old. Schiff bases, also known as azomethines or imines, are compounds that in a broad sense possess the general formula R3R2C=NR1. The substituents R2 and R3 may be alkyl, phenyl, heteroaryl, hydrogen. The substituent R1 at the N- imino (C=N) may be alkyl, phenyl, heteroaryl, hydrogen or a metal (generally Si, Al, B, Sn). A Schiff base derived from aniline, where R3 is a phenyl or a substituted phenyl, can be called an anil. Thus, Schiff bases can be considered as a nitrogen analogue of an aldehyde or ketone in which the carbonyl group (C=O) has been replaced by an imine or azomethine group. The name “Organic Bases” first appeared in a German paper entitled “EineneueReiheorganischerBasen” (“A New Series of Organic Bases”) [1], though, they are not used as bases in the conventional sense, the designation of these compounds as bases, has persisted up to the present time. The chemistry of Schiff’s bases originated, when Schiff [ 1-9] reported the reaction between aniline with aldehydes. The method involved Dean Stark apparatus for removal of water molecule. Figure 1 Synthetic protocol and general structure of amine Schiff’s bases readily form complexes with a variety of metals. The imino N atom is frequently employed for co-ordination with the metals. This has led to opening of new avenues for the chemical and biological profiles of Schiff’s bases. Literatur e survey reveals that metal-Schiff’s base complexes exhibits a range of anti-bacterial, anti-fungal, anti-cancer, etc. in micro to sub nanomolar range. This promising aspect of Schiff’s base complexes has been the subject of study in the last decade [1 -9].In the present work, the newly synthesized ligands and their complexes [10] with different 3D-series elements have been subjected to pharmacophore analysis.