International Journal of Advanced Research in Chemical Science (IJARCS) Volume 3, Issue 8, August 2016, PP 1-8 ISSN 2349-039X (Print) & ISSN 2349-0403 (Online) http://dx.doi.org/10.20431/2349-0403.0308001 www.arcjournals.org ©ARC Page | 1 Copper (II) Complexes of New Carboxyamide Ligands: Synthesis, Spectroscopic and Antibacterial Study P. Ramesh 1,2, , M.Revathi 1, Ammar Adil.H 1 , N.A.AL-Satar Mohammeda 1 , S. Siddappa 1 , P. Muralidhar Reddy 1* , Chand Pasha 3* 1 Department of Chemistry, Nizam College, Osmania University, Hyderabad, India 2 Department of Chemistry, S.R&B.G.N.R. Government College, Khammam, India 3 Department of Microbiology, Nizam College, Osmania University, Hyderabad, India pmdreddy@gmail.com, cpasha21@gmail.com Abstract: Copper (II) complexes with three carboxyamide ligands viz.2 (phenylcarbamoyl) benzoic acid (PCBCH),(Z)-4-(2-nitrophenylamino)-4-oxobut-2-enoic acid (NPAOEH) and (2Z, 2’Z)-4, 4’-(1,2-phenylenebis (azanediyl)) bis (4-oxobut-2-enoic acid) (PEAOBH) have been synthesized and characterized by UV-Visible, Infrared and 1 H-NMR spectral data. Analytical data support 1: 2 stoichiometry for metal: ligand. The molar conductivity data indicate that the complexes are non-electrolytic in nature. The electronic spectra suggests distorted octahedral geometry for Cu (II) complexes. The antibacterial activity of all the ligands and complexes against gram-positive and gram-negative bacteria was compared with the activity of existing commercial antibacterial compound like Streptomycin. All metal complexes found to be more active than respective ligands. Keywords: Antibacterial activity, Carboxyamide Ligand, Copper complexes 1. INTRODUCTION The amide group, an important structural feature of proteins, can be described as resonating between two structures (Fig.1), one with the double bond between the carbon atom and the oxygen atom, and the other with the double bond between the carbon atom and the nitrogen atom 1 . O N R 2 H R 1 O - N + R 2 R 1 H Structure ‘a’ Structure ‘b’ Fig1. Resonance structures of amide group General arguments about the stability of alternative structures indicate that the structure with the double bond between carbon and oxygen should contribute somewhat more to the normal state of the amide group than the other structure; experience with other substances and acquaintance with the results of quantum mechanical calculations suggest the ratio 60%: 40% for the respective contributions of these structures. A 40% contribution of the structure with the double bond between the carbon atom and the nitrogen atom would confer upon this bond the property of planarity of the group of six atoms. The estimate of 40% double-bond character for the C-N bond is supported by the experimental value of the bond length, 1.32 Å, interpreted with the aid of the empirical relation between double-bond character and inter-atomic distance 2 . Knowledge of the structure of amides and also of the amino acids, provided by the theory of resonance and verified by extensive careful experimental studies made by R. B. Corey and his coworkers, has been of much value in the determination of the structure of the amide complexes. It is known that the amide groups to retain their planarity, the atoms are expected not to deviate from the planar configuration by more than perhaps 0.05 Å.Amide group being the repeating unit of the biologically important polypeptide