Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13(D), 81377, Munich, Germany.
Chemistry. 2018 Oct 22;24(59):15825-15830. doi: 10.1002/chem.201804009. Epub 2018 Oct 17.
This study shows that the anomeric effect (negative hyperconjugation) that arises in sulfamide, as a result of the relatively short S-N bonds, can be tuned by the utilization of superacidic media. Sulfamide was reacted in binary superacidic systems XF/MF (M=As, Sb; X=H, D) and HF/BF . The colorless salts formed, [X NSO NX ] [MF ] and [H NSO NH ] [BF ] were characterized by low-temperature vibrational spectroscopy. In the case of [H NSO NH ] [BF ] , a single crystal X-ray diffraction study was performed. The salt crystallizes in the monoclinic space group P2 /c with four formula units per unit cell. An exclusive N,N'-diprotonation was observed in the superacidic system HF/SbF when using several equivalents of the Lewis acid. Low-temperature vibrational spectra as well as a single-crystal X-ray structure of [H NSO NH ] 2 [SbF ] ⋅2 HF are reported. The salt crystallizes in the orthorhombic space group Pna2 with four formula units per unit cell. Upon mono- or diprotonation of sulfamide, remarkable structural changes of the sulfur-nitrogen bond lengths were observed. Herein, these changes are discussed together with quantum chemical calculations.
这项研究表明，由于相对较短的 S-N 键，磺酰胺中会出现端基效应（负超共轭效应），可以通过利用超强酸介质来进行调节。磺酰胺在二元超强酸体系 XF/MF（M=As、Sb；X=H、D）和 HF/BF 中进行反应。形成的无色盐[X NSO NX ] [MF ]和[H NSO NH ] [BF ]通过低温振动光谱进行了表征。对于[H NSO NH ] [BF ]，进行了单晶 X 射线衍射研究。该盐在单斜空间群 P2 /c 中结晶，每个晶胞有四个分子式单元。当使用几个路易斯酸当量时，在超强酸体系 HF/SbF 中观察到了独特的 N,N'-二质子化。报道了低温振动光谱以及[H NSO NH ] 2 [SbF ] ⋅2 HF 的单晶 X 射线结构。该盐在正交空间群 Pna2 中结晶，每个晶胞有四个分子式单元。磺酰胺单质子化或双质子化后，观察到硫-氮键长度发生了显著的结构变化。本文还结合量子化学计算讨论了这些变化。
