Vogt Linda I, Cotelesage Julien J H, Dolgova Natalia V, Titus Charles J, Sharifi Samin, George Simon J, Pickering Ingrid J, George Graham N
Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan Saskatoon Saskatchewan S7N 5E2 Canada
Department of Physics, Stanford University Stanford California 94305 USA.
RSC Adv. 2020 Jul 13;10(44):26229-26238. doi: 10.1039/d0ra04653a. eCollection 2020 Jul 9.
Organic sulfoxides, a group of compounds containing the sulfinyl S[double bond, length as m-dash]O group, are widespread in nature, important in health and disease, and used in a variety of applications in the pharmaceutical industry. We have examined the sulfur K-edge X-ray absorption near-edge spectra of a range of different sulfoxides and find that their spectra are remarkably similar. Spectra show an intense absorption peak that is comprised of two transitions; a S 1s → (S-O)σ* and a S 1s → [(S-O)π* + (S-C)σ*] transition. In most cases these are sufficiently close in energy that they are not properly resolved; however for dimethylsulfoxide the separation between these transitions increases in aqueous solution due to hydrogen bonding to the sulfinyl oxygen. We also examined tetrahydrothiophene sulfoxide using both the sulfur and oxygen K-edge. This compound has a mild degree of ring strain at the sulfur atom, which changes the energies of the two transitions so that the S 1s → [(S-O)π* + (S-C)σ*] is below the S 1s → (S-O)σ*. A comparison of the oxygen K-edge X-ray absorption near-edge spectra of tetrahydrothiophene sulfoxide with that of an unhindered sulfoxide shows little change, indicating that the electronic environment of oxygen is very similar.
有机亚砜是一类含有亚磺酰基S=O基团的化合物，在自然界中广泛存在，在健康与疾病方面具有重要意义，并在制药行业有多种应用。我们研究了一系列不同亚砜的硫K边X射线吸收近边光谱，发现它们的光谱非常相似。光谱显示出一个由两个跃迁组成的强吸收峰；一个S 1s→(S - O)σ跃迁和一个S 1s→[(S - O)π+(S - C)σ*]跃迁。在大多数情况下，这些跃迁的能量足够接近，以至于无法得到很好的分辨；然而，对于二甲基亚砜，由于与亚磺酰基氧形成氢键，在水溶液中这两个跃迁之间的间距会增大。我们还使用硫和氧的K边研究了四氢噻吩亚砜。该化合物在硫原子处有一定程度的环张力，这改变了两个跃迁的能量，使得S 1s→[(S - O)π*+(S - C)σ*]跃迁低于S 1s→(S - O)σ*跃迁。将四氢噻吩亚砜的氧K边X射线吸收近边光谱与一种无阻碍亚砜的光谱进行比较，发现变化很小，这表明氧的电子环境非常相似。
