A solvent-resistant halogen bond
A solvent-resistant halogen bond
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DOI：
10.1039/c4sc01746c
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发表时间：
2014-09
期刊：
影响因子：
8.4
通讯作者：
C. Robertson;R. Perutz;L. Brammer;C. Hunter
中科院分区：
文献类型：
--
作者：
C. Robertson;R. Perutz;L. Brammer;C. Hunter
溶剂对含氢键或卤素键（X键）的配合物稳定性的影响已被量化。用紫外维斯吸收光谱和~ 1HNMR滴定法测定了4-（苯基偶氮）苯酚、分子碘、四甲基脲和四甲基硫脲在15种不同溶剂中的缔合常数。氢键复合物的稳定性随溶剂极性的增加而降低三个数量级以上。相比之下，分子碘与四甲基硫脲的X-键合络合物对溶剂的性质非常不敏感（在烷烃和醇中测量的缔合常数是相似的）。结果表明，在相反的H-键，静电确定热力学稳定性，电荷转移相互作用作出了重大贡献，这些X-键合的复合物的稳定性，使它们耐溶剂极性的增加。
The effect of solvent on the stabilities of complexes involving a single H-bond or halogen-bond (X-bond) has been quantified. Association constants for binary complexes of 4-(phenylazo)phenol, molecular iodine, tetramethylurea and tetramethylthiourea have been measured in fifteen different solvents by UV/vis absorption and 1H NMR titration experiments. The stabilities of the H-bonded complexes decrease by more than three orders of magnitude with increasing solvent polarity. In contrast, the X-bonded complex of molecular iodine with tetramethylthiourea is remarkably insensitive to the nature of the solvent (association constants measured in alkanes and alcohols are similar). The results suggest that, in contrast to H-bonds, where electrostatics determine thermodynamic stability, charge-transfer interactions make a major contribution to the stability of these X-bonded complexes rendering them resistant to increases in solvent polarity.