Investigation of the Lipophilicity of 2-Benzoylpyridine-Thiosemicarbazone Based on the Ion Transfer across the Liquid/Liquid Interface

• Published in: Wuli huaxue xuebao Vol. 24; no. 4; pp. 619 - 624
• Main Author: AKGEMCI Emine G BINGOL Haluk OZCELIK Mehmet ERSOZ Mustafa
• Format: Journal Article
• Language: Chinese
• Published: 01.04.2008
• Subjects: 化学结构; 抗菌剂; 离子; 缩氨基硫脲
• ISSN: 1000-6818
• DOI: 10.1016/S1872-1508(08)60028-5

The ion transfer reaction of 2-benzoylpyridine-thiosemicarbazone （HL）, which has antimicrobial and antifungal properties and anticancer activity, has been studied to determine its lipophilicity by cyclic voltammetry at the water/1,2-dichloroethane （1,2-DCE） interface. The physicochemical parameters such as standard partition coefficient （lgPI）andthestandardGibbsenergyoftransfer（△Gtr,I^0,w→o）oftheprotonatedformoftheligandwere measured asa function of pH in aqueous phase. The protonated form of the ligand exhibited reversible or quasi-reversible voltammograms at the1,2-DCEintherangeofpH15.Theprotonationconstantsoftheligand,pKa1andpKa2,weredeterminedspectrophotometrically and were found to be 12.14 and 3.24, respectively. The standard Gibbs energy of transfer （△Gtr,N^0,w→o） and the partition coefficient of neutral species （lgPN） were also determined by the shake-flask method. The standard Gibbs energy of transfer of this compound across the water/1,2-DCE interface was evaluated as the quantitative measure of its lipophilicity. The difference between lgPI and lgPN was related to the degree of charge delocalization and was used to evaluate qualitatively the lipophilicity of the ligand.