Unusual Saddle-like Structure of (2-MeOC6H4CS)2S: Theoretical Studies and Comparison with its Oxygen Isologue
Unusual Saddle-like Structure of (2-MeOC6H4CS)2S: Theoretical Studies and Comparison with its Oxygen Isologue
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(2-MeOC6H4CS)2S的异常鞍状结构：理论研究及其氧同工物的比较
DOI：
10.1002/zaac.201200357
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发表时间：
2012
影响因子：
1.4
通讯作者：
W. Nakanishi
中科院分区：
文献类型：
--
作者：
O. Niyomura;Y. Kito;S. Kato;M. Ishida;M. Ebihara;S. Hayashi;W. Nakanishi
化合物（2-MeOC 6 H4 CS）2S（1）显示了一种不寻常的鞍形结构，其中-C（=S）-S-C（=S）-部分是平面的，两个苯环面对面，中心硫原子和两个2-甲氧基氧原子之间的距离（3.07 nm）在两个原子的货车范德华半径之和内。然而，在B3 LYP/6 - 311+G（2d，p）水平上的MO计算结果表明，两个原子之间没有轨道相互作用。从MP2水平上的计算结果可以推断，由于晶体的有效体积较小，因此晶体堆积效应对于这种密集堆积的晶体是重要的。另一方面，其中两个甲氧基氧原子不能与中心硫原子接触的对甲氧基衍生物（4-MeOC 6 H4 CS）2S（2）显示L形结构，其中-C（=S）-S-C（=S）-部分不是平面的。化合物（2-MeOC 6 H4 CO）（2-MeOC 6 H4 CS）S（3b）中的-C（=O）-S-C（=S）-结构为L型结构，尽管两个甲氧基氧原子与中心硫原子处于分子内接触。化合物1和2的深蓝色至绿色以及化合物3的深紫色分别是由于硫代羰基硫原子的HOMO（HOMO 87）中的孤对电子跃迁至LUMO（HOMO 89）以及硫代羰基硫原子的HOMO（HOMO 83）中的孤对电子跃迁至LUMO（HOMO 85）。
Compound (2‐MeOC6H4CS)2S (1) showed an unusual saddle structure in which the –C(=S)–S–C(=S)– moiety is planar and two benzene rings lie a face‐to‐face and the distances (3.07 Å) between the central sulfur atom and two 2‐methoxy oxygen atoms are within the sum of van der Waals radii of the both atoms. However, the results of MO calculation at the B3LYP/6‐311+G(2d, p) level showed no orbital interaction between both atoms. From the results of the calculations at the MP2 level, it was deduced that the crystal packing effect is important for such densely packed crystal, due to its less effective volume. On the other hand, thepara‐methoxy derivative (4‐MeOC6H4CS)2S (2) in which the two methoxy oxygen atoms are not able to contact with the central sulfur atom shows anL‐shaped structure in which the –C(=S)–S–C(=S)– moiety is not planar. The –C(=O)–S–C(=S)– moiety in compound (2‐MeOC6H4CO)(2‐MeOC6H4CS)S (3b) shows anL‐shaped structure, though the two methoxy oxygen atoms are in intramolecular contact with the central sulfur atom. The deep blue to green colors of compounds1and2and the deep violet color of compound3bare due to transitions of the lone‐pair electrons in the HOMO (ψ87) of the thiocarbonyl sulfur atom to the LUMO (ψ89)and of those in the HOMO (ψ83) of the thiocarbonyl sulfur atom to the LUMO (ψ85), respectively.