Tuning and dissecting electronic and steric effects in ammonium receptors: Nonactin vs artificial receptors
Tuning and dissecting electronic and steric effects in ammonium receptors: Nonactin vs artificial receptors
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DOI：
10.1021/ja0174175
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发表时间：
2002-05-15
影响因子：
15
通讯作者：
Kim, K
中科院分区：
文献类型：
--
作者：
Chin, J;Oh, J;Kim, K
离子选择电极（ISE）基于三种不同的三足受体（5,6和7）已经研究了传感铵离子。每个受体都是基于三个吡唑基团，可以从结合的铵离子中接受三个氢键。基于4-溴-3,5-二甲基吡唑(6)的受体最敏感，在pH 8下对铵离子的检测限为2.5 × 10(-5) M。基于2,3-二甲基吡唑(5)和未取代吡唑(7)的受体的检出限分别为1,0 × 10(-4) M和2.0 × 10(-4) M。受体5、6和7对铵离子对钾离子(logK(NH4)(-)/(+)(K))的选择性分别为-2.8、-2.3和-1.7。相比之下，基于非肌动蛋白的ISE的检测限和选择性分别为2.2 x 10(-5) M和-1.3。晶体学研究表明，受体6接受来自结合铵的3个氢键，单质子化受体5与结合水分子形成3个氢键。
Ion selective electrodes (ISE) based on three different tripodal receptors (5, 6, and 7) have been investigated for sensing ammonium ion. Each receptor is based on three pyrazole groups that can accept three H-bonds from the bound ammonium ion. The receptor based on 4-bromo-3,5-dimethylpyrazole (6) is the most sensitive with a detection limit for ammonium ion of 2.5 x 10(-5) M at pH 8. The detection limits for the receptors based on 2,3-dimethylpyrazole (5) and unsubstitued pyrazole (7) are 1,0 x 10(-4) and 2.0 x 10(-4) M, respectively. The selectivities of the receptors 5, 6, and 7 for sensing ammonium ion over potassium ion (logK(NH4)(-)/(+)(K)) are -2.8, -2.3, and -1.7, respectively. In contrast, the detection limit and the selectivity of a nonactin-based ISE are 2.2 x 10(-5) M and -1.3, respectively. Crystallographic studies reveal that 6 accepts three H-bonds from the bound ammonium and singly protonated receptor 5 forms three H-bonds with the bound water molecule.