Co2+与BPPT络合反应动力学及动力学光谱法测定钴

Thiosemicarbazones and phenylthiosemicarbazones are in- teresting ligands because of their ability to form highly stable and intensely colored complexes, which is attributed to the for- mation of bond between sulfur and hydrazino nitrogen atoms, and these…     

液/液界面电子转移研究苯甲酰吡啶-缩氨基硫脲的亲脂性

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 (IgP1) and the standard Gibbs energy of transfer (△G0,w→otr,I) of the protonated form of the ligand were measured as a function of pH in aqueous phase. The protonated form of the ligand exhibited reversible or quasi-reversible voltammograms at the 1,2-DCE in the range of pH 1-5. The protonation constants of the ligand, pKal, and pK? were determined spectrophotometrically and were found to be 12.14 and 3.24, respectively. The standard Gibbs energy of transfer (△G0,w→otr,N) and the partition coefficient of neutral species (IgPN) 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 lgP1 and lgPN was related to the degree of charge delocalization and was used to evaluate qualitatively the lipophilicity of the ligand.     

噻二嗪衍生物的合成及Pb2+在水/1,2-二氯乙烷界面转移的电化学性质

The transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine(PPTA) at the polarized water/1,2-dicholoroethane(1,2-DCE) interface was investigated by cyclic voltammetry.We synthesized the thiadiazine derivative,PPTA,firstly.The transfer was performed at different metal concentrations and scan rates,and the obtained voltammetric transfer peaks toward Pb2+ ion over other divalent cations(Zn2+,Co2+,Ni2+,Cd2+,Hg2+,and Cu2+) were reversible.The dependence of the half-wave potentials of the Pb2+ ion on the concentration of PPTA in the organic phase indicates that the ion transfer is facilitated by the formation of 1:2(metal:ligand) complex in the organic phase with the association constant(lgβ2) of(17.1±0.2).     

Co2+与BPPT络合反应动力学及动力学光谱法测定钴

Kinetics of complexation reaction of Co2+ with 2-benzoylpyridine-4-phenyl-3-thiosemicarbazone (BPPT)was spectrophotometrically examined at 421 nm. The ligand that is developed for a simple kinetic-spectrophotometric determination of Co2+ is based on 1:2 complex formation between Co2+ and BPPT. The complexation reaction was carried out in ethanol-water medium at 25 ℃. Kinetic and activation parameters of the complexation reaction were calculated, and the rate equation and the reaction mechanism were proposed. The calibration graph is linear in the concentration range of 0.10～2.91 mg·L-1 for the tangent method. The species that caused interference were investigated.