Octamethyl-octaundecylcyclo[8]pyrrole: A promising sulfate anion extractant
Octamethyl-octaundecylcyclo[8]pyrrole: A promising sulfate anion extractant
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DOI：
10.1021/ja074568k
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发表时间：
2007-09-12
影响因子：
15
通讯作者：
Moyer, Bruce A.
中科院分区：
文献类型：
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作者：
Eller, Leah R.;Stepien, Marcin;Moyer, Bruce A.
发现有机增溶的环[8]吡咯衍生物的双质子化形式，在P-吡咯位置上带有八个十一烷基链，可以有效地从中性水介质中萃取硫酸根阴离子到甲苯有机相中。发现在不存在相转移催化剂Aliquat 336-硝酸盐（A336 N）的情况下，两相之间的硫酸根阴离子交换的动力学非常慢，但在其存在下是明显的。该环[8]吡咯的二硝酸根阴离子结合形式可以通过使最初含有0.5 mM硫酸根阴离子结合形式和0.1 mM三辛胺（TOA）的甲苯相用0.1 M HNO 3水溶液连续平衡直到在水相中不再检测到硫酸根而原位产生。当在0.1mM（TOAH）（+）（NO3-）存在下，以0.5mM的甲苯溶液研究这种双硝酸盐络合物时，也发现它是硫酸根阴离子的有效萃取剂。在1 M NaNO 3（aq）和0.3 mM NaNO 3（aq）下分别观察到D（SO 4）值为0.001和1000，条件交换常数的对数log（K '（exch））计算为4.9 +/- 0.4。因此，本发明的环[8]吡咯系统是值得注意的，因为它是第一个在溶剂萃取条件下在过量硝酸根存在下对硫酸根阴离子显示出高选择性的合成受体。
The diprotonated form of an organic-solubilized cyclo[8]pyrrole derivative, bearing eight undecyl chains on the P-pyrrolic positions, was found to extract sulfate anion effectively from neutral aqueous media into a toluene organic phase. The kinetics of sulfate anion exchange between the two phases were found to be exceedingly slow in the absence of the phase-transfer catalyst, Aliquat 336-nitrate (A336N), but appreciable in its presence. The bisnitrate anion bound form of this cyclo[8]pyrrole could be generated in situ by subjecting the toluene phase containing initially 0.5 mM of the sulfate anion bound form and 0.1 mM trioctylamine (TOA) to successive equilibrations with aqueous 0.1 M HNO3 until sulfate was no longer detected in the aqueous phase. This bisnitratecomplex, when studied as a 0.5 mM solution in toluene in the presence of 0.1 mM (TOAH)(+)(NO3-), was also found to be an effectiveextractant for sulfate anion. D (SO4) values of 0.001 and 1000 were observed at 1 M NaNO3(aq) and 0.3 mM NaNO3(aq), respectively,and the logarithm of the conditional exchange constant, log(K'(exch)), was calculated to be 4.9 +/- 0.4. The present cyclo[8]pyrrole system is thus noteworthy as being the first synthetic receptor that displays a high selectivity for sulfate anion in the presence of excess nitrate under conditions of solvent extraction.