Comparative study of aromaticity in five‐membered rings containing S, SO and SO2 groups
Comparative study of aromaticity in five‐membered rings containing S, SO and SO2 groups
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含S、SO、SO2基团五元环芳香性的比较研究
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发表时间：
1992
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通讯作者：
I. Rozas
中科院分区：
文献类型：
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作者：
I. Rozas
由于芳香性概念的重要性，已经开发了不同的指数来试图量化这一特性。通过XSOnX基团（X = C，N; n = 0，1或2）的可能的π离域可以解释含有该部分的环中的杂芳性。因此，我们研究了不含噻吩、含1个异噻唑或含2个1，2，5-噻二唑的不同氧化数（S、SO和SO2）的五元含硫环的芳香性。进行了从头计算，以确定几何参数（平面的环，键长和键级），电子结构（电荷分布和偶极矩）和参与的d-轨道的硫。根据这些计算，只有含S（II）的化合物才能被认为是芳香族的，而含S（IV）或S（VI）的化合物更好地描述为叶立德。
Owing to the importance of the concept of aromaticity, different indices have been developed to try to quantify this property. The possible π delocalization through an XSOnX group (X = C, N; n = 0, 1 or 2) could explain heteroaromaticity in rings containing the moiety. For that reason, the aromaticity of five-membered sulphurcontaining rings with different oxidation numbers (S, SO and SO2) and including no (thiophene), one (isothiazole) or two (1,2,5-thiadiazole) adjacent atoms was investigated. Ab initio calculations were carried out to determine geometrical parameters (planarity of the ring, bond length and bond order), electronic structure (charge distribution and dipolar moment) and the participation of d-orbitals of sulphur. According to these calculations, only compounds with S(II) can be considered to be aromatic, whereas compounds bearing S(IV) or S(VI) are better described as ylides.