%0 Journal Article
%T Electron Donor-Acceptor Interaction of 8-Hydroxyquinoline with Citric Acid in Different Solvents: Spectroscopic Studies
%A Demelash Jado
%A Khalid Siraj
%A Nathan Meka
%J Journal of Applied Chemistry
%D 2014
%R 10.1155/2014/484361
%X Charge transfer complex formation between 8-hydroxyquinoline as the electron donor and citric acid as the electron acceptor has been studied spectrophotometrically in ethanol and methanol solvents at room temperature. Absorption band due to charge transfer complex formation was observed near 320 and 325£¿nm in ethanol and methanol, respectively. The stoichiometric ratio of the complex has been found 3£¿:£¿1 by using Job¡¯s and conductometric titration methods. Benesi-Hildebrand equation has been applied to estimate the formation constant and molecular extinction coefficient. It was found that the value of formation constant was larger in ethanol than in methanol. The physical parameters, ionization potential, and standard free energy change of the formed complex were determined and evaluated in the ethanol and methanol solvents. 1. Introduction Mulliken also showed that the charge transfer interactions within a molecular complex consisting of an electron donor (ED) and an electron acceptor (EA) involved a resonance with a transfer of charge from ED to EA [1, 2]. Charge-transfer complexes result from a donor-acceptor mechanism of Lewis acid-base reaction between two or more different chemical constituents. The formation of electron-donor acceptor (EDA) complexes can be rapidly assessed for its validity as a simple quantitative analytical method for many drug substances which can act as electron donors. Charge transfer complexes have been studied exclusively due to their wide application as ion sensors in the field of environmental science and in the determination of drugs based on the charge-transfer (CT) complexes formed with electron acceptors [3¨C5]. They also can be used as organic semiconductors photo catalysts, dendrimers, and in the studying of redox processes [6]. More recently, attention has been given to the isolation and investigation of physical properties of some CT-complexes in the solid states. Some of these complexes show interesting electrical conductivity properties and have found applications in many forms of electronics and solar cells [7]. Charge transfer complexation is currently to achieve the great importance in biochemical, bioelectrochemical energy transfer process, biological systems, and drug-receptor binding mechanism, for examples, drug action, enzyme catalysis, and ion transfers through lipophilic membranes [8]. Recently, many studies have been widely reported about the rapid interactions between different kinds of drugs and related compounds as donors like morpholine, norfloxacin, ciprofloxacin, and sulfadoxine, with several
%U http://www.hindawi.com/journals/jac/2014/484361/