Macrocycles Containing Tin. 119Sn NMR Studies of Chloride Binding by Lewis Acidic Tin Compounds. Multidentiate Effects, Macrocyclic Effects and Size Selectivity.
Macrocycles Containing Tin. 119Sn NMR Studies of Chloride Binding by Lewis Acidic Tin Compounds. Multidentiate Effects, Macrocyclic Effects and Size Selectivity.
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含锡大环化合物。
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
J. Judice
中科院分区：
文献类型：
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作者：
M. Newcomb;A. Madonik;M. T. Blanda;J. Judice
摘要：合成了三个大环刘易斯酸主体，其结构与无环二锡模型（5，5，16，16-四氯-5，16-二锡二十二烷，4）相同，均含有两个对称排列的二氯锡（1-3，环尺寸分别为18，22，26原子）。用~（119）Sn NMR研究了1-4和二丁基二氯化锡（5）在乙腈中与氯离子的络合作用。锡原子之间的氯离子的快速交换发生在所有比例的氯离子主机研究。使用迭代计算机程序来提供1、2、4和5与氯的结合常数的估计。进行竞争实验，其中两种二锡主体竞争有限的氯离子，并分析混合物的119 Sn NMR光谱以确定由每种主体结合的氯离子的相对量，从而确定在后面的研究中发现的结合常数的比率和在前面的研究中发现的绝对结合常数的比率。计算了结合能。的二锡主机表现出合作的双齿效应结合氯离子相比，5导致结合能的增加超过预测的统计校正的网站数量的量。环状主体1-3比非环状模型4更强地结合氯离子（大环效应）。宿主1比宿主2更强地结合氯（尺寸选择性效应）。（作者）。
Abstract : Three macrocyclic Lewis acidic hosts containing two symmetrically disposed dichlorostanna moieties (1-3, ring sizes 18, 22, 26 atoms, respectively) have been prepared as has an acyclic di-tin model (5,5,16,16-tetrachloro-5,16-distannadocosane, 4). The complexation of 1-4 and dibutyltin dichloride (5) with chloride ion in acetonitrile was studied by 119Sn NMR spectroscopy. Rapid exchange of chloride between tin atoms occurred at all ratios of chloride to host studied. An iterative computer program was used to provide estimates of the binding constants of 1, 2, 4 and 5 with chloride. Competition experiments were performed wherein two di-tin hosts competed for limited chloride ion, and the 119Sn NMR spectra of the mixtures were analyzed to determine the relative amount of chloride bound by each host and hence the ratio of the binding constants found in the latter studies and the ratios of the absolute binding constants found in the former studies. The energies of binding were calculated. The di-tin hosts exhibited cooperative bidentate effects in binding chloride in comparison to 5 leading to an increase in binding energy over the amount predicted for a statistical correction in the number of sites. The cyclic hosts 1-3 bind chloride more strongly than acyclic model 4 (macrocyclic effect). Host 1 binds chloride somewhat more strongly than host 2 (size-selective effect). (Author).