Structural Features of Tetraazathiapentalenes Fused with Pyrimidine and/or Pyridine Rings. Experimental Evaluation of the Nature of Hypervalent N−S−N Bond by Restricted Internal Rotation of the Pyrimidine Ring
dimethylated (17) 10-S-3 sulfuranes, derivatives of tetraazathiapentalenes fused with pyrimidine and/or pyridine ring, were prepared. These molecules are planar, and bond energies of the hypervalent N−S−N bond were evaluated by the temperature dependent restrictedrotation of the pyrimidine ring caused by cleavage of one of the S−N bonds. The bond length is longer, and the energy is lower for the S−N bond
制备了一系列中性 (8-10)、单甲基化 (12-14) 和二甲基化 (17) 10-S-3 硫烷,四氮杂硫戊烯与嘧啶和/或吡啶环稠合的衍生物。这些分子是平面的,高价 NS-N 键的键能通过由 SN 键之一断裂引起的嘧啶环的温度依赖性限制旋转来评估。与更多吸电子杂环稠合的 SN 键的键长更长,能量更低。