title: Spectral, thermal and kinetic studies of charge-transfer complexes formed between the highly effective antibiotic drug metronidazole and two types of acceptors: σ- and π-acceptors.
abstract: Understanding the interaction between drugs and small inorganic or organic molecules is critical in being able to interpret the drug-receptor interactions and acting mechanism of these drugs. A combined solution and solid state study was performed to describe the complexation chemistry of drug metronidazole (MZ) which has a broad-spectrum antibacterial activity with two types of acceptors. The acceptors include, σ-acceptor (i.e., iodine) and π-acceptors (i.e., dichlorodicyanobenzoquinone (DDQ), chloranil (CHL) and picric acid (PA)). The molecular structure, spectroscopic characteristics, the binding modes as well as the thermal stability were deduced from IR, UV-vis, (1)H NMR and thermal studies. The binding ratio of complexation (MZ: acceptor) was determined to be 1:2 for the iodine acceptor and 1:1 for the DDQ, CHL or PA acceptor, according to the CHN elemental analyses and spectrophotometric titrations. It has been found that the complexation with CHL and PA acceptors increases the values of enthalpy and entropy, while the complexation with DDQ and iodine acceptors decreases the values of these parameters compared with the free MZ donor.
authors: Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, Zip Code 21974 Taif, Saudi Arabia; Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt. Electronic address: msrefat@yahoo.com.
authors: Moamen S
authors: MS
authors: Refat
authors: Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, Zip Code 21974 Taif, Saudi Arabia; Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt.
authors: Hosam A
authors: HA
authors: Saad
authors: Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, Zip Code 21974 Taif, Saudi Arabia.
authors: Abdel Majid A
authors: AM
authors: Adam
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry; D002703:Chloranil / Q000737:chemistry; D004583:Electrons; D019277:Entropy; D007455:Iodine / Q000737:chemistry; D007700:Kinetics; D008795:Metronidazole / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D013818:Thermogravimetry; D014732:Vibration
chemical_list: D000900:Anti-Bacterial Agents; D016227:Benzoquinones; D010851:Picrates; D002703:Chloranil; D008795:Metronidazole; C000928:dichlorodicyanobenzoquinone; D007455:Iodine; C005858:picric acid
keywords: Charge-transfer complex; Metronidazole; TG and DTG; π-Acceptor; σ-Acceptor