Gavazov Kiril Blazhev, Delchev Vassil Borisov, Mileva Kremena Tomova, Stefanova Teodora Stefcheva, Toncheva Galya Kostadinova
Acta Chim Slov. 2016;63(2):392-8. doi: 10.17344/acsi.2016.2431.
The complex formation in the vanadium(V)/4-(2-thiazolylazo)orcinol (TAO)/2,3,5-triphenyl-2H-tetrazolium chloride (TTC) liquid-liquid extraction-chromogenic system was studied. The chloroform-extracted complex has a composition of 2:2:2 under the optimum conditions (pH 4.8-5.2, extraction time 3 min, concentration of TAO 3.4 × 10(-4) mol dm(-3), and concentration of TTC 9.4 × 10(-4) mol dm(-3)) and could be regarded as a dimer (D) of two 1:1:1 species (S) presented by the formula (TT+)[VO2(TAO)]. The constant of extraction was calculated by two methods and some analytical characteristics were determined. The wavelength of maximum absorption (λmax), molar absorptivity (ελ) and fraction extracted (E) were found to be λ = 545 nm, ε545 = 1.97 × 10(4) dm(3) mol(-1) cm(-1), and E = 97.9%. The ground-state equilibrium geometries of the complexes S and D were optimized by quantum chemical Hartree-Fock calculations using 3-21G* basis functions. The bonding and interaction energies were calculated as well.
研究了钒（V）/4-（2-噻唑基偶氮）邻苯二酚（TAO）/2,3,5-三苯基-2H-氯化四唑（TTC）液-液萃取-显色体系中的配合物形成情况。在最佳条件下（pH 4.8 - 5.2，萃取时间3分钟，TAO浓度3.4×10⁻⁴ mol dm⁻³，TTC浓度9.4×10⁻⁴ mol dm⁻³），氯仿萃取的配合物组成为2:2:2，可视为由式（TT⁺）[VO₂（TAO）]表示的两个1:1:1物种（S）的二聚体（D）。通过两种方法计算了萃取常数并测定了一些分析特性。发现最大吸收波长（λmax）、摩尔吸光率（ελ）和萃取率（E）分别为λ = 545 nm，ε545 = 1.97×10⁴ dm³ mol⁻¹ cm⁻¹，E = 97.9%。使用3-21G*基函数通过量子化学哈特里-福克计算优化了配合物S和D的基态平衡几何结构。还计算了键能和相互作用能。
