Halili Jeton, Berisha Avni
Department of Chemistry, FNMS, University of Pristina "Hasan Prishtina", Pristina, Republic of Kosovo.
Turk J Chem. 2021 Dec 27;46(3):721-729. doi: 10.55730/1300-0527.3362. eCollection 2022.
For more than five decades, dithizone has been widely used as an analytical reagent. This ligand forms strongly colored complexes with metal ions and this ability to form complexes can be used for extraction/removal of certain metal ions in addition to analytical determination. In static mode, the supercritical carbon dioxide extraction of copper and lead ions from aqueous solutions after complexation by the dithizone ligand is studied (at two different conditions: a) p = 120 bar, T = 30 °C, and b) p = 72 bar, T = 50 °C). The addition of methanol improved the extraction process by modulating the polarity of the extraction medium. Atomic absorption spectroscopy (AAS) is used to determine the concentration of metal ions before and after extraction. We use density functional theory (DFT) [model chemistry: using m-GGA/M11-L] to better understand the binding energy and geometry of bidentate ligands produced from dithizone and copper(II) or lead(II) ions. Furthermore, the developed complexes' noncovalent interactions (NCI), bond order analysis, and electron localization function (ELF) provided valuable details about these molecules. To elucidate the bidentate complex extraction mechanism formed between the heavy metal ions and the dithizone ligand, molecular dynamic simulations at periodical boundary conditions were performed using the universal force field to obtain precise molecular descriptions.
五十多年来,双硫腙一直被广泛用作分析试剂。这种配体与金属离子形成颜色很深的络合物,除了用于分析测定外,这种形成络合物的能力还可用于萃取/去除某些金属离子。在静态模式下,研究了在双硫腙配体络合后,从水溶液中用超临界二氧化碳萃取铜离子和铅离子的情况(在两种不同条件下:a)p = 120巴,T = 30°C,b)p = 72巴,T = 50°C)。加入甲醇通过调节萃取介质的极性改善了萃取过程。原子吸收光谱法(AAS)用于测定萃取前后金属离子的浓度。我们使用密度泛函理论(DFT)[模型化学:使用m-GGA/M11-L]来更好地理解双硫腙与铜(II)或铅(II)离子生成的双齿配体的结合能和几何结构。此外,所形成络合物的非共价相互作用(NCI)、键级分析和电子定域函数(ELF)提供了有关这些分子的有价值细节。为了阐明重金属离子与双硫腙配体之间形成的双齿络合物萃取机理,使用通用力场在周期性边界条件下进行了分子动力学模拟,以获得精确的分子描述。