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

双冠醚衍生物能够通过两个相邻冠醚环的协同作用更选择性地与尺寸略大于冠醚空腔的碱金属阳离子络合。这些衍生物可能是立体异构体的混合物，然而，迄今为止，作为伊势中性载体进行了研究。由于手性中心的存在，Na^+被包裹在两个冠醚环之间的空腔中的立体化学效应似乎是相当大的。因此，首先，合成了光学活性的双（12-冠-4），（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得双（12-冠-4）的Na^+选择性。测定了这些新型光学活性双（12-冠-4）基电极对碱金属和碱土金属阳离子的Na^+选择性系数， ...更多信息 用固定干涉法测定。以<pot>2.8%的光学活性双（12-冠-4）为新载体，邻硝基苯基辛基醚（NPOE）为增塑溶剂介体，四[3，5-二（三氟苯基）硼酸钠（NaHFPB）为阴离子排斥剂，在PVC基体中得到最佳的选择性（logk^ _=-2.3）。与先前报道的光学惰性双（12-冠-4）相比，使用（R，R）-或（S，S）-双（12-冠-4）时，Na^+对K^+的选择性增加了近两倍。FAB-MASS方法研究表明，冠醚与Na^+、K^+络合能力的差异决定了其上级Na^+选择性。在（R，R）型双（15-冠-5）基电极中，NPOE得到了较好的结果，<pot>与光学惰性的双（15-冠-5）衍生物相比，具有较高的K^+选择性（logk^ _=-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