Department of Chemical Sciences, Faculty of Pharmacy, Medical University of Plovdiv, 120 Buxton Bros Str., 4004 Plovdiv, Bulgaria.
Faculty of Chemistry, University of Plovdiv 'Paisii Hilendarskii', 24 Tsar Assen St., 4000 Plovdiv, Bulgaria.
Molecules. 2023 Mar 8;28(6):2484. doi: 10.3390/molecules28062484.
Four azo dyes known to form anionic complexes with V(V) were investigated as potential liquid-liquid extraction-spectrophotometric reagents for the antihistamine medication hydroxyzine hydrochloride (HZH). A stable ion-association complex suitable for analytical purposes was obtained with 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR). The molar absorption coefficient, limit of detection, linear working range, and relative standard deviation in the analysis of real pharmaceutical samples (tablets and syrup) were 3.50 × 10 L mol cm, 0.13 μg mL, 0.43-12.2 μg mL, and ≤2.7%, respectively. After elucidating the molar ratio in the extracted ion-association complex (HZH:V = 1:1), the ground-state equilibrium geometries of the two constituent ions-HZH and [VO(HTAR)]-were optimized at the B3LYP level of theory using 6-311++G** basis functions. The cation and anion were then paired in four different ways to find the most likely structure of the extracted species. In the lowest-energy structure, the VO group interacts predominantly with the heterochain of the cation. A hydrogen bond is present (V-O···H-O; 1.714 Å) involving the terminal oxygen of this chain.
四种偶氮染料已知与 V(V) 形成阴离子配合物，被研究为潜在的用于反组胺药物盐酸羟嗪 (HZH) 的液液萃取分光光度试剂。与 6-己基-4-(2-噻唑偶氮)间苯二酚 (HTAR) 获得了适合分析目的的稳定的离子缔合配合物。摩尔吸光系数、检测限、线性工作范围和在实际药物样品（片剂和糖浆）分析中的相对标准偏差分别为 3.50×10 L mol cm、0.13μg mL、0.43-12.2μg mL 和 ≤2.7%。在阐明萃取的离子缔合配合物中的摩尔比（HZH:V = 1:1）后，使用 6-311++G**基函数在 B3LYP 理论水平上优化了两个组成离子-HZH 和 [VO(HTAR)]-的基态平衡几何形状。然后以四种不同的方式将阳离子和阴离子配对，以找到提取物种的最可能结构。在最低能量结构中，VO 基团主要与阳离子的杂链相互作用。存在氢键（V-O···H-O；1.714Å），涉及该链的末端氧。
