Evaluation of heavy metal ion discrimination and application of entropic host molecule to soft metal ion sensor

虽然碱金属和碱土金属离子载体分子设计的方向性已经确定，但对于重金属和过渡金属离子载体的方向性还没有确定。本文对23种席夫碱进行了电化学表征，考察了它们的方向性，以提高银离子的识别能力。其中，由α-异亚硝基苯丙酮和1，3-丙二胺衍生的N，N '-双（2'-羟基亚氨基-1 '-苯基亚丙基）-1，3-丙二胺（PHO 3）被认为是最实用的Ag^+离子载体。即PHO_3-NPOE_（I）&gt;（增塑剂）-KTpCl_（PB_（II））&gt;（阴离子排斥剂）体系PVC_（III）&gt;膜电极在5.0 × 10 ~ 4 ~ 7.9 × 10 ~ 4 mol·dm ~（-1）范围内对Ag ~（2+）有较宽的活度变化，具有良好的能斯特响应<-7><-7><-3>。用固定干扰法计算，Ag^+离子相对于K^+离子的选择性-log k^<pot>_&lt;Ag，K&gt;为3.35。该电极H 关于我们 唯一的缺点是寿命短，只有20天左右。因此，PHO 3的甲基部分被转化到长链烷基中以改善亲油性。在含长链烷基的席夫碱中，N，N '-双（2'-羟基亚氨基-1 '-苯基丁叉基）-1，3-丙二胺，PHEtO 3基NPOE-KTpClPB体系电极在两个多月的观察期内表现出了上级的性能，但由于席夫碱的水解，Ag^+对K^+的选择系数从4.35逐渐降低到2.95。此外，为了考察配位原子的数目对银离子选择性络合的影响，合成了三种三齿配体，并与类似的四齿配体PHO 3进行了比较。3-（2-吡啶基乙基单）-2-丁酮肟（Me-PyO_3）具有一个肟和一个吡啶取代基，是银离子电极的最佳载体。基于Me-PyO 3的PVC膜电极表现出良好的Ag^+离子选择性，-logk ^<pot>_&lt;Ag，K&gt;=3.8，与四齿PHO 3相当，除了假能斯特响应（3.6 mV decade ^[1]），Ag^+离子的活度变化范围从5.0 × 10 ^ mol dm ^<-7>[2]到7.9 × 10 ^<-2>mol dm^<-3>[2]。I）：聚氯乙烯; II）：邻硝基苯基辛基醚; III）：四（4-氯苯基）硼酸钾

Though the directivity of the molecular design of the ionophore for alkali and alkaline-earth metal ion has been established, it has not been established for the heavy and transition metal ionophore. In the present work, twenty-three kinds of Schiff bases were characterized by electrochemical measurement to examine the directivity for improving the silver-ion discrimination ability. Among the Schiff bases, N, N'-bis(2'-hydroxyimino-1'-phenylpropylidene)-1, 3-propanediamine, PHO3, derived from α-isonitrosopropiophenone and 1, 3-diaminopropane was found to be the most practical Ag^+-ionophore. That is, PHO3-NPOE^<I)>(plasticizer)-KTpC1PB^<II)>(anion excluder) system PVC^<III)> membrane electrode gave good results with a Nernstian response in accordance with the wide Ag^+ activity change in the activity range 5.0x10^<-7> to 7.9x10^<-7> mol dm^<-3>. The Ag^+ ion selectivity with respect to K^+ ion, -log k^<pot>_<Ag, K> was 3.35 evaluated by fixed interference method, FIM. This electrodes h … More as the only defect to be a short life time in about 20 days. Therefore, methyl moiety of PHO3 was converted in the long-chain alkyl groups in order to improve the lipophilicity. Among the Schiff based having long alkyl unit, N, N'-bis(2'-hydroxyimino-1'-phenylbuthylidene)-1, 3-propanediamine, PHEtO3 based NPOE-KTpC1PB system electrode showed superior performance during an observation period of more than 2 months, though the Ag^+ selectivity coefficient with respect to K^+, was gradually reduced from 4.35 to 2.95 due to the hydrolysis of Schiff bases. Further, to examine the effect of the number of coordination atom on selective complexation with Ag ion, three kinds of tridentate ligands were synthesized and compared with similar quadoridentate ligand, PHO3. 3-(2-pyridyleethylimono)-2-butanoneoxime, Me-PyO3, having one oxime and a pyridine substituent was found to be the best ionophore for Ag ion electrode. The PVC membrane electrode based on Me-PyO3 exhibit good Ag^+ ion selectivity, -logo k^<pot>_<Ag, K>=3.8, comparable to that of quadridentate PHO3, except for pseudo Nernstian response(3.6mV decade^1) with a wide Ag^+-ion activity change in the activity change from 5.0x10^<-7> to 7.9x10^<-2>mol dm^<-3>.I) : poly (vinyl chloride) ; II) : o-nitorophenyl octyl ether ; III) : potassium tetrakis (4-chlorophenyl) borate Less