Drug Design, Development and Therapy (Oct 2020)
Charge Transfer Complex of Neostigmine with 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone: Synthesis, Spectroscopic Characterization, Antimicrobial Activity, and Theoretical Study
Abstract
Tarek A Yousef,1,2 Essam Ezzeldin,3,4 Hatem A Abdel-Aziz,5 Mohamed H Al-Agamy,6,7 Gamal AE Mostafa3,5 1College of Science, Chemistry Department, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Kingdom of Saudi Arabia; 2Department of Toxic and Narcotic Drug, Forensic Medicine, Mansoura Laboratory, Medicolegal Organization, Ministry of Justice, Mansoura, Egypt; 3Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; 4Bioavailability Laboratory, Central Laboratory, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; 5Applied Organic Chemistry Department, National Research Center, Cairo 12622, Egypt; 6Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; 7Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, EgyptCorrespondence: Gamal AE Mostafa Email [email protected]: Electron donor–acceptor interactions are important molecular reactions for the activity of pharmacological compounds. The aim of the study is to develop a charge transfer (CT) complex: synthesis, characterization, antimicrobial activity, and theoretical study.Method and Results: A solid CT complex of neostigmine (NSG) with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was synthesized and characterized by infrared spectra, NMR, and UV–visible spectroscopy. The results confirm the formation of a CT complex. The stability of the CT complex between NSG and DDQ in acetonitrile was determined in solution via spectrophotometric measurement, ie, by calculating the formation constant, molar extinction coefficient, and different spectroscopic parameters. The stoichiometry of the formed NSG–DDQ complex was determined using Job’s method. The absorption band of the NSG–DDQ complex can be used for the quantification of NSG.Conclusion: The DFT geometry optimization of NSG, DDQ, and the CT complex and the UV comparative study of both theoretical and experimental structures are presented. The experimental results confirm the charge transfer structure. The bacterial study shows that the NSG–DDQ complex has good antibacterial activity against both Gram-positive and Gram-negative bacteria as well as antifungal activity against Candida albicans.Keywords: charge transfer complex, neostigmine, DDQ, synthesis, spectroscopic, characterization, antimicrobial activity, theoretical study
