Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Dep. de Química, Fac. Ciencias. Exactas, UNLP, CC 16 Suc. 4, B1904DPI, La Plata, Argentina.
J Mol Model. 2013 Jun;19(6):2183-8. doi: 10.1007/s00894-013-1761-8. Epub 2013 Jan 24.
In this letter, we study the effect of cation charge on anion selectivity in the pore using grand canonical Monte Carlo simulations. The mechanism of anion selectivity inside nanopores was found to be primarily a consequence of the screening of negative charges by the cations. In the case of monovalent cations, screening was not very effective and anions were rejected. We found an 'off-state' at high pH and an 'on-state' at low pH. When there are divalent cations, screening is good and there is no rejection of the anion. The concentration of anions at high pH is similar to that at low pH. The system is always in an 'on-state'. Trivalent cations show an inverse selectivity mechanism: at high pH the concentration is higher than at low pH, i.e., the pore is in the 'on-state' at high pH and in the 'off-state' at low pH.
在这封信中，我们使用巨正则蒙特卡罗模拟研究了孔中阳离子电荷对阴离子选择性的影响。发现纳米孔内阴离子选择性的机制主要是阳离子对负电荷的屏蔽。在单价阳离子的情况下，屏蔽效果不是很好，阴离子被排斥。我们在高 pH 值下发现了“关闭状态”，在低 pH 值下发现了“开启状态”。当存在二价阳离子时，屏蔽效果很好，阴离子不会被排斥。高 pH 值下的阴离子浓度与低 pH 值下的浓度相似。系统始终处于“开启状态”。三价阳离子表现出相反的选择性机制：在高 pH 值下，浓度高于低 pH 值，即孔在高 pH 值下处于“开启状态”，在低 pH 值下处于“关闭状态”。
