Transfer activity coefficients of crown ethers and their complexes with univalent metal ions between pairs of polar organic solvents
Transfer activity coefficients of crown ethers and their complexes with univalent metal ions between pairs of polar organic solvents
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冠醚及其与一价金属离子的络合物在极性有机溶剂对之间的转移活度系数
DOI：
10.1007/bf00646436
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发表时间：
1988
影响因子：
1.2
通讯作者：
I. Kolthoff
中科院分区：
文献类型：
--
作者：
M. K. Chantooni;G. Roland;I. Kolthoff
从碱金属离子或银离子与二苯并取代冠醚（L=DB-18-cr-6，DB-21-cr-7，DB-24-cr-8，DB-30-cr-10）络合物在碳酸丙烯酯与溶剂S2之间的转移活度系数[γ（LM+）]PC，2的比较可以得出结论：在络合物LM+中，L和M+都被溶剂化，特别是在高配位度的溶剂中，N，N-二甲基甲酰胺。从DB-30-cr-10 K+在乙腈中的异常低的离子迁移率和离子对DB-30-cr-10 KBr的高值缔合常数可以得出结论，在形成配体分离的离子对时，外部溶剂壳被剥离。只有当L为18-cr-6、B-18-cr-6或DB-18-cr-6时，[log γ（LM+）] PC，2与[logγ（M+）]PC，2才有线性关系。大分子二苯并冠醚配合物的线性偏离归因于L。结果表明，18-cr-6、DB-18-cr-6和DB-30-cr-10在乙腈中的溶解比在甲醇中的溶解更容易受到焓的辅助，而在甲醇中溶解的熵更有利。
From a comparison of transfer activity coefficients, [γ(LM+)]PC,2between propylene carbonate and solvent S2of alkali or silver ions complexed with dibenzo-substituted crown ethers (L=DB-18-cr-6, DB-21-cr-7, DB-24-cr-8, DB-30-cr-10) it can be concluded that in the complex LM+both L and M+are solvated, particularly in solvents of high donicity, e.g., N,N-dimethylformamide. From the abnormally low ionic mobility of DB-30-cr-10K+in acetonitrile and the high value of the association constant of the ion pair DB-30-cr-10KBr it is concluded that the outer solvent shell is stripped upon formation of the ligand separated ion pair. A linear relation is found between [log γ(LM+)]PC,2and [logγ(M+)]PC,2only when L is 18-cr-6, B-18-cr-6, or DB-18-cr-6. Deviation from the linearity of complexes of the larger dibenzo crown ethers is attributed to the flexibility of L. It is shown that solution of 18-cr-6, DB-18-cr-6 and DB-30-cr-10 is enthalpy assisted to a greater extent in acetonitrile than in methanol, while the entropy of solution is more favorable in the latter.