Solid-State 23Na Nuclear Magnetic Resonance of Sodium Complexes with Crown Ethers, Cryptands, and Naturally Occurring Antibiotic Ionophores: A Direct Probe to the Sodium-Binding Sites
Solid-State 23Na Nuclear Magnetic Resonance of Sodium Complexes with Crown Ethers, Cryptands, and Naturally Occurring Antibiotic Ionophores: A Direct Probe to the Sodium-Binding Sites
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DOI：
10.1021/jp002096p
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发表时间：
2000-12
影响因子：
2.9
通讯作者：
A. Wong;Gang Wu
中科院分区：
文献类型：
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作者：
A. Wong;Gang Wu
我们报告了一项系统的固态23Na核磁共振研究，研究了钠与冠醚、隐蔽体和自然产生的抗生素离子载体的络合物。通过对~(23)Na魔角自旋(MAS)核磁共振谱的分析，确定了~(23)Na四极耦合常数和化学位移的精确信息。我们发现，实验上的~(23)Na化学位移可以与一个经验参数有关，该参数是给体配体的原子价、Na+−配位距离和感兴趣的Na+离子周围配位数(Cn)的函数。在氯化镉溶液中测得的~(23)Na四极杆参数与在固体中测得的参数之间也有很好的相关性，表明在氯化镉溶液中阳离子交换较慢。而在甲醇溶液中，Na-−离子载体络合物的23Na四极参数和化学位移与相应的固态数据均无相关性。最后，我们报道了Na(12C4)2ClO4：δ中的23Na化学位移张量。
We report a systematic solid-state 23Na nuclear magnetic resonance study of sodium complexes with crown ethers, cryptands, and naturally occurring antibiotic ionophores. Precise information about 23Na quadrupole coupling constants and chemical shifts was determined from analysis of 23Na magic-angle spinning (MAS) NMR spectra. We found that the experimental 23Na chemical shifts can be related to an empirical parameter that is a function of the atomic valence of the donor ligand, the Na+−ligand distance, and the coordination number (CN) around the Na+ ion of interest. A reasonably good correlation was also observed between the 23Na quadrupole parameters measured in CDCl3 solution and those measured in the solid state, indicating that the cation exchange is slow in CDCl3. In MeOH solution, however, neither 23Na quadrupole parameters nor chemical shifts of the Na−ionophore complexes show correlation with the corresponding solid-state data. Finally, we report the 23Na chemical shift tensor in Na(12C4)2ClO4: δ...