The Distribution of Charge Density of Hypervalent Organic Sulfur Compounds

Hypervalent compounds如sigma-sulfanes和thiathiophthenes在结构化学和有机合成中具有巨大的利益。两种四氮杂化合物衍生物I和II的电子密度分布，与1.90 - 1.96 A的典型超饱和S-N债券在被调查时被订购在超饱和债券的字符上遮蔽，并与这些硫原子的电子特征相比较。二苯并噻吩衍生物的电子密度分布， III，带有一个较弱的内部分子S...与3.012 A也被调查。Intensities of X-ray Diffraction were measured at 143 K up to 2 rhetamax =100？（88？for III） and the structure refinements were performed using multiple expansion atomic scManagement ing factors up to the hexadecapole expansion for S atom。在四氮杂对苯二甲烯飞机的模型变形图中，S-N债券周围的正电子密度接近于硝基原子，而不是在债券中心。网络原子电荷是从多个重精炼建议使用的S-N债券的极化字符。对于每一个化合物，两对单口电张力可以在该区段观察到通过S-C债券的五角大楼平面。C-S-L，C-S-L '和L-S-L' （L和L' =单对密度峰值）约120个角度。围绕超电压原子结构是一个带有对等sp^2的S-C键和单对电子和appolarized S-N键的三角双氨基酸混合体。在第三层单对电子密度被观察到硫醚环和C-S-C硫醚平面。两个硫醚组的单对电子的Lobes of lone-pair electrons是orthonormal，每个人都有两个S原子之间的一对单对电子。

Hypervalent compounds such as sigma-sulfuranes and thiathiophthenes are of great interest in structural chemistry and organic synthesis. Electron-density distributions of two tetraazathiapentalene derivatives, I and II,with typical hypervalent S-N bonds of 1.90 - 1.96 A were investigated in order to shed light on the character of hypervalent bonds and to compare electronic features of these sulfur atoms. Electron-density distributions of dibenzothiophene derivative, III,with a weak intramolecular S・・・S contact of 3.012 A were also investigated. Intensities of X-ray diffraction were measured at 143K up to 2rhetamax=100ﾟ (88ﾟ for III) and the structure refinements were performed using multipole expansion atomic scattering factors up to the hexadecapole expansion for S atom. In model-deformation maps of the tetraazathiapentalene planes, positive electron densities along S-N bonds are observed near the nitrogen atoms, not in the center of the bonds. The net atomic charges derived from the multipole refinement suggest a polarized character of S-N bond. For each compound, two lone-pair electron densities are observed in the section perpendicular to the pentalene plane through the S-C bonds. The angles of C-S-L,C-S-L' and L-S-L' (L and L' = peaks of lone-pair densities) are about 120ﾟ.Structure around the hypervalent S atom is a trigonal bipyramid with equatorial sp^2 hybrid of S-C bond and lone-pair electrons and apical polarized S-N bonds. In III lone-pair electron densities are observed perpendicular to the thiophene ring and the C-S-C sulfide planes. Lobes of lone-pair electrons of two sulfide groups are orthonormal with each other to avoid a steric hindrance between lone pairs of two S atoms.