~ 222 ~  International Journal of Chemical Studies 2019; 7(4): 222-227                     P-ISSN: 2349–8528  E-ISSN: 2321–4902 IJCS 2019; 7(4): 222-227 © 2019 IJCS Received: 14-05-2019 Accepted: 22-06-2019   H Muglu Department of Chemistry, Faculty of Science, Kastamonu University, Kastamonu, Turkey MS Çavuş Biomedical Engineering Department, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu, Turkey Corresponding Author: H Muglu Department of Chemistry, Faculty of Science, Kastamonu University, Kastamonu, Turkey Synthesis, characterization and Quantum Chemical Calculations of 2-chloroacetamido -5-(2- chloroacetamido-1, 3, 4-thiadiazolyl)-1, 3, 4- Thiadiazole Derivatives H Muglu and MS Çavuş Abstract 2-chloroacetamido-5-(2-chloroacetamido-1,3, 4-thiadiazolyl)-1,3, 4-Thiadiazole, bis(2-chloroacetamido- 1,3,4-thiadiazolyl)methane, 1,4-di(2-chloroacetamido -1,3,4- thiadiazolyl) benzene were synthesized, and molecular characterizations was carried out by the elemental analyses. Experimentally obtained 1 H NMR and FT-IR spectroscopic data were supported by DFT calculations using B3LYP/cc-pvtz method. Electronic parameters such as electronegativity, chemical hardness, polarizability and dipole moment were also calculated and analyzed. Experimental data of the compounds were compared with theoretical results. Intramolecular interactions of Cl−NH and S−O were performed using Bader's QTAIM approach. Keywords: Thiadiazole, UV-Vis, FT-IR, DFT 1. Introduction Although many antimicrobial drugs have been invented to prevent infectious diseases since ancient times, the change and resistance of microbes in the life cycle has improved [1] . The development of drug-resistant microorganisms has reached worldwide concern and the synthesis of new anti-infective compounds has become an urgent need for the treatment of microbial infections [2] . In recent years, heterocyclic ring systems have been of great interest in medical chemistry research because of interesting biological and synthetic applications [3] . Therefore, numerous heterocyclic compounds such as thiazoles, thiadiazoles, oxadiazoles and pyrroles; antibacterial, anticancer, antipyretic, hypoglycemic, antihypertensive, anti- inflammatory and anti-HIV4 reagents were synthesized. In addition, heterocyclic molecules are used in agriculture, plastics, polymers, dyes and textiles. Thus, heterocyclic chemistry continues to attract the attention of synthetic organic chemists [4-7] . Heterocyclic compounds such as thiadiazole is a five-membered ring system containing two nitrogen atoms and one sulphur atom with conjugated p and π electrons. They are present in four isomeric forms; 1,2,3-thiadiazole, 1,2,5-thiadiazole, 1,2,4-thiadiazole and 1,3,4- thiadiazole. 1,3,4-thiadiazoles, the most studied species, are used in agriculture and in many technological fields [8, 9] . In this study, 2-chloroacetamido -5-(2-chloroacetamido-1,3,4-thiadiazolyl)-1,3,4-Thiadiazole, bis(2-chloroacetamido-1,3,4-thiadiazolyl)methane,1,4-di(2-chloroacetamido-1,3,4- thiadiazolyl) benzene were synthesized, and characterized experimentally and theoretically. The synthesized compounds were performed by using density functional theory (DFT) calculations and compared with the experimental results of FT-IR and 1 H NMR spectroscopies. Furthermore, intramolecular interactions of Cl−NH and S−O were analyzed by Bader's QTAIM approach. 2. Materials and methods Di-(2- amino-1,3,4-thiadiazoles) were synthesized with the reaction of dicarboxylic acids and thiosemicarbazide in the presence of POCl3. The bands of IR spectra observed at 3370 cm -1 , 3264 cm -1 belonging to the N-H and 1636 cm -1 , 1629cm -1 belonging to the C=N stretching band and bending vibration respectively and H-NMR /ppm 7.70, 7.55, 7.19 (s, 4H, -NH2 protons) supports that bis (2 amino-1,3,4-thiadiazole (Scheme 1).