作者:Charles L. Perrin、Yifan Wu
DOI:10.1021/jacs.8b13785
日期:2019.3.6
The enols of 4-cyano-2,2,6,6-tetramethyl-3,5-heptanedione and of nitromalonamide were prepared as statistical mixtures of 18O n ( n = 0, 1, 2) isotopologues. The symmetries of their hydrogen bonds were probed by isotopic perturbation of their 13CO NMR signals. The former mixture shows a total of four signals, due to both intrinsic and perturbation isotope shifts. Therefore, that enol is a mixture of
4-氰基-2,2,6,6-四甲基-3,5-庚二酮和硝基丙二酰胺的烯醇制备为 18O n (n = 0, 1, 2) 同位素体的统计混合物。通过其 13CO NMR 信号的同位素扰动探测了它们氢键的对称性。由于固有和扰动同位素位移,前一种混合物总共显示四个信号。因此,该烯醇是具有不对称氢键的互变异构体的混合物。相比之下,硝基丙二酰胺烯醇的同位素混合物仅显示两个信号,这是由于固有的同位素位移。因此,与 FHF- 阴离子相比,这是第一种在溶液中具有单一对称结构且具有中心氢的中性物种的情况。