Synthesis, crystal structures and competitive binding property of a family of calix[4]arene-biscrown-5/6 and their application in extraction of alkali metal ions from sea bittern
Synthesis, crystal structures and competitive binding property of a family of calix[4]arene-biscrown-5/6 and their application in extraction of alkali metal ions from sea bittern
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DOI：
10.1016/j.poly.2015.07.001
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发表时间：
2015-11
期刊：
影响因子：
2.6
通讯作者：
Vallu Ramakrishna;E. Suresh;Vinod P. Boricha;A. Bhatt;P. Paul
中科院分区：
文献类型：
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作者：
Vallu Ramakrishna;E. Suresh;Vinod P. Boricha;A. Bhatt;P. Paul
合成了一类在杯单元的上下边缘均含有冠醚部分且氮杂冠醚部分的氮原子上连接有不同取代基的杯[4]芳烃化合物，对其进行了表征，并研究了它们在水溶液中与Li+、Na+、K+、Mg 2+、Ca 2+和Sr 2+的竞争结合性能。这些离子载体表现出对K+的高选择性，通过两相萃取方法，然后通过离子色谱法测定提取物中的金属离子进行评估。采用等温量热滴定法测定了与K+形成配合物的化学计量、结合常数和其他热力学参数（ΔH、ΔSand ΔG）。为了在溶液中进行结构解析，进行了详细的1H NMR研究，并分离出K+络合物用于固态表征。通过单晶X-射线研究确定了两种离子载体和其中一种离子载体的K+-络合物的分子结构。1H NMR、ITC和单晶XRD研究表明，K+在冠-6环的上边缘形成了1：1的络合物。这些离子载体已被应用于从盐卤中提取金属离子。
A family of calix[4]arene compounds containing crown moieties at both the upper and lower rims of the calix unit with different substituents attached to the nitrogen atom of the aza-crown moiety have been synthesized, characterized and their competitive binding property towards Li+, Na+, K+, Mg2+, Ca2+and Sr2+in aqueous media has been investigated. These ionophores exhibit high selectivity towards K+, assessed by two-phase extraction method followed by ion chromatographic assay of the metal ions in the extract. Isothermal calorimetric titration for complex formation with K+was carried out to evaluate stoichiometry, binding constant and other thermodynamic parameters (ΔH, ΔSand ΔG). For structural elucidation in solution, detail1H NMR study was carried out and K+complexes were isolated for solid state characterization. Molecular structures of two of the ionophores and K+-complex of one of the ionophores has been established by single crystal X-ray study.1H NMR, ITC and single crystal XRD studies suggest 1:1 complex formation with encapsulation of K+in the crown-6 ring at the upper rim. These ionophores have been applied for extraction of metal ions from bittern.