In Vitro Bacterial Screening and Degradation Kinetics of a Terpolymer Ligand and Its Transition Metal Complexes MOHAMED A. RISWAN AHAMED Department of Chemistry, Oxford Engineering College, Tiruchirappalli 620 009, India RAJA S. AZARUDEEN Department of Chemistry, Coimbatore Institute of Technology, Coimbatore 641 014, India N. PRABU Functional Materials Division, Central Electrochemical Research Institute, Karaikudi 630 006, India ABDUL R. BURKANUDEEN PG and Research Department of Chemistry, Jamal Mohamed College (Autonomous), Tiruchirappalli 620 020, India Correspondence to: Mohamed A. Riswan Ahamed; e-mail: polyrizwan@gmail.com. Received: March 15, 2014 Accepted: June 30, 2014 ABSTRACT: A novel terpolymer ligand involving 2-amino-6-nitro-benzothiazole–semicarbazide–formaldehyde was synthesized in a 1:1:2 mole ratio with a dimethylformamide reaction medium at 150 ± 2°C for 6 h. The synthesized ligand was used to prepare various metal complexes with Cu 2+ , Ni 2+ , and Zn 2+ metal ions. The structure of the terpolymer ligand and its complexes were conﬁrmed based on elemental analysis, molecular weight measurements, molar conductivity, magnetic susceptibilities, Fourier transform infrared, electronic, electron spin resonance, and 1 H and 13 C nuclear magnetic resonance spectroscopy. Scanning electronic microscopy and X-ray diffraction method were used to analyze the morphological features of the terpolymer and its metal complexes. The thermal stabilities of the terpolymer and its metal complexes were determined using thermogravimetric analysis. Kinetic parameters such as activation energy (E a ) and order of reaction (n), thermodynamic parameters, viz. entropy change (S), free energy change (F), apparent entropy (S*), and frequency factor (Z) were calculated using Sharp–Wentworth and Freeman–Carroll methods. The thermal degradation mechanism was also proposed for both the terpolymer ligand and its complexes using the Phadnis–Deshpande method. The terpolymer ligand and its complexes were screened for antibacterial activities against selected microorganisms such as Shigella sonnei, Escherichia coli, Klebsiella species, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhimurium. C  2014 Wiley Periodicals, Inc. Adv Polym Technol 2014, 00, 21460; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21460 KEY WORDS: Biological applications of polymers, Metal–Polymer complexes, Morphology, Polycondensation, Thermogravimetric analysis Introduction P olymers and polymer-based materials are ubiquitous in modern society. They have been used extensively as lig- ands in the ﬁeld of coordination chemistry. 1–3 For a long time, aromatic heterocyclic polymers were studied for their advan- tages such as complex-forming ability, 4,5 thermal stability, 6,7 and Dedicated to Dr. A. Burkanudeen, who died on December 28, 2012 in a road accident. various biomedical applications. 8 These chelating ligands con- taining N, O, and S donor atoms show broad biological activity and are of special interest because of the variety of ways in which they are bonded to metal ions. 9 The incorporation of transition metal ions into polymeric ligands not only affect the physical characteristics but also the chemical activity. 10 A variety of heterocyclics, particularly thiazoles take up an important part owing to their versatile bioactivities due to the presence of multifunctional groups. 11–13 Thiazole and its derivatives play a signiﬁcant part in the animal kingdom. Vitamin B 1 , penicillin, and coenzyme cocarboxylase contain mainly the thiazole ring. Hence, the thiazole derivatives are Advances in Polymer Technology, Vol. 00, No. 0, 2014, DOI 10.1002/adv.21460 C  2014 Wiley Periodicals, Inc. 21460 (1 of 15)