Quantum mechanical prediction of the magnetic titration curve of a nitroxide 'spin probe'
Quantum mechanical prediction of the magnetic titration curve of a nitroxide 'spin probe'
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DOI：
10.1016/s0009-2614(01)00076-8
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发表时间：
2001-03-16
影响因子：
2.8
通讯作者：
Barone, V
中科院分区：
文献类型：
--
作者：
Improta, R;Scalmani, G;Barone, V
用量子力学方法研究了2，2，5，5，四甲基-4，甲基咪唑啉氮氧自由基的磁性随包埋介质pH值的变化。氮氧自由基的超精细耦合常数由混合QCISD/PBE 0计算确定，而中性和质子化的氮氧自由基的几何形状和相对解离常数在PBE 0水平上计算。溶剂效应建模包括几个明确的溶剂分子（强烈绑定到溶质），并通过使用CPCM方法。计算的滴定曲线和实验的滴定曲线之间的协议是相当不错的，证实了我们的计算策略的可靠性。(C)2001 Elsevier Science B. V.保留所有权利。
The variation of the magnetic properties of 2,2,5,5,tetrametyhl-4,methyl-imidazoline nitroxide with the pH of the embedding medium is investigated by means of quantum mechanical calculations. The hyperfine coupling constants of the nitroxide are determined by mixed QCISD/PBE0 calculations, while the geometry of the neutral and protonated nitroxide and the relative dissociation constants are calculated at the PBE0 level. Solvent effects are modelled both by including a few explicit solvent molecules (strongly bound to the solute) and by using the CPCM method. The agreement between the calculated and the experimental titration curve is quite good, confirming the reliability of our computational strategy. (C) 2001 Elsevier Science B.V. All rights reserved.