Estimation of functionality and application of optically active bis (crown ethet) to ion sensor

双（冠醚）衍生物可以通过相邻的两个冠醚环的配合作用，更有选择性地结合比冠醚腔略大的碱金属阳离子。然而，这些衍生物可能是立体异构体混合物，迄今为止被研究为ISE中性载体。由于手性中心的存在，立体化学对Na^+被包封到两个冠醚环之间的空腔中的影响似乎是相当大的。因此，首先合成了具有光学活性的双（12-冠-4）s、（R，R）型2-癸基-2-甲基丙二酸酯衍生物、（R，R）型二苄基丙二酸酯衍生物和（s, s）型2-癸基-2-甲基丙二酸酯衍生物，并通过电化学测量评价了所合成的双（12-冠-4）s的Na^+选择性。用固定干涉法测定了这些新型光学活性双（12-冠-4）基电极对碱和碱土金属阳离子的Na^+选择性系数。在PVC基质中，以光学活性双（12-冠-4）为中性载体、以邻硝基辛基醚（NPOE）为增塑溶剂介质、以四[3,5-双（三氟苯）]硼酸钠（NaHFPB）为阴离子排除剂的传感器选择性最佳（logk^<pot>_=-2.3）。使用（R，R）-或（S，S）-bis （12-crown-4）的Na^+对K^+的选择性比先前报道的非旋光性bis (12-crown-4) S的选择性提高了近两倍。FAB-MASS方法表明，Na^+的选择性取决于Na^+和K^+络合冠的差异。其次，合成了四种双（15-冠-5）衍生物，并对K^+选择性进行了类似的估计。在（R，R）型bis (15-crown-5)s基电极中，NPOE给出了良好的结果，与光学非活性bis （15-crown-5）衍生物相比，它具有较高的K^+选择性（logk^<pot>_=-3.4）。少

Bis (crown-ether) derivatives are able to bind alkali metal cation, which has a little larger size than the cavity of a crown ether, more selectively by cooperative action of their two adjacent crown ether rings on complexation. These derivativers which might be stereoisomeric mixtures, however, so far were investigated as an ISE neutral carrier. The effect of stereochemistry due to the presence of a chiral center on the encapsulation of Na^+ into the cavity between two crown ether rings seems to be considerable. Therefore, at the first, optically active bis (12-crown-4)s, (R,R)-type 2-decyl-2-methylmalonate derivative, (R,R)-type dibenzylmalonate derivative, and (S,S)-type 2-decyl-2-methylmalonate derivative, were synthesized and Na^+-selectivity of resulting bis (12-crown-4)s were evaluated by electrochemical measurement. The Na^+-selectivity coefficient with respect to alkali and alkaline earth metal cation for these new optically active bis (12-crown-4) based electrodes were determ … More ined by fixed interference method. The best selectivity (logk^<pot>_=-2.3) was obtained when the sensons containing optically active bis (12-crown-4) as newtral carrier in 2.8 % were used in association with o-nitorophenyl octyl ether (NPOE) as a plasticizing solvent mediator and sodium tetrakis [3,5-bis (trifluorophenyl] borate (NaHFPB) as an anion excluder in PVC matrices. Na^+ selectivity against K^+ was augmented by a factor of nearly two using (R,R)- or (S,S)-bis (12-crown-4) compared with that of optically inactive bis (12-crown-4)s reported previously. FAB-MASS method revealed that superior Na^+ selectivity was depend on difference in the complexation crown with Na^+ and K^+.At the second, four kinds of bis (15-crown-5) derivatives were also synthesized and K^+-selectivity were similarly estimated. In the (R,R)-type bis (15-crown-5)s based electrodes, NPOE gave good results, allowing high K^+-selectivity (logk^<pot>_=-3.4) compared with that of optically inactive bis (15-crown-5) derivatives. Less