کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1405222 | 1501750 | 2014 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Complexation of the sodium cation with sodium ionophore III: Experimental and theoretical study Complexation of the sodium cation with sodium ionophore III: Experimental and theoretical study](/preview/png/1405222.png)
• Stability of the Na+ – sodium ionophore III complex was determined.
• Quantum mechanical DFT calculations were carried out.
• Structures of the nonhydrated and hydrated cationic complexes were predicted.
By using extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Na+(aq) + A−(aq) + 1(nb) ⇄⇄ 1·Na+(nb) + A−(nb) occurring in the two-phase water – nitrobenzene system (A− = picrate, 1 = sodium ionophore III; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (1·Na+, A−) = 1.5 ± 0.1. Further, the stability constant of the 1·Na+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Na+) = 6.7 ± 0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the nonhydrated 1·Na+ and hydrated 1·Na+·2H2O cationic complex species were derived. In both of these complexes, the “central” cation Na+ is bound by four bonding interactions to the corresponding four oxygen atoms of the parent ligand 1. Besides, in the case of 1·Na+·2H2O complex, the considered hydrated structure is stabilized by two water molecules bound to the “central” sodium cation.
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Journal: Journal of Molecular Structure - Volume 1067, 5 June 2014, Pages 216–219