Winnewisser Gisbert, Lewen Frank, Thorwirth Sven, Behnke Markus, Hahn Josef, Gauss Jürgen, Herbst Eric
I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937 Köln, Germany.
Chemistry. 2003 Nov 21;9(22):5501-10. doi: 10.1002/chem.200305192.
Gas-phase oxadisulfane (HSOH), the missing link between the well-known molecules hydrogen peroxide (HOOH) and disulfane (HSSH), was synthesized by flash vacuum pyrolysis of di-tert-butyl sulfoxide. Using mass spectrometry, the pyrolysis conditions have been optimized towards formation of HSOH. Microwave spectroscopic investigation of the pyrolysis products allowed-assisted by high-level quantum-chemical calculations--the first measurement of the rotational-torsional spectrum of HSOH. In total, we have measured approximately 600 lines of the rotational-torsional spectrum in the frequency range from 64 GHz to 1.9 THz and assigned some 470 of these to the rotational-torsional spectrum of HSOH in its ground torsional state. Some 120 out of the 600 lines arise from the isotopomer H(34)SOH. The HSOH molecule displays strong c-type and somewhat weaker b-type transitions, indicating a nonplanar skew chain structure, similar to the analogous molecules HOOH and HSSH. The rotational constants (MHz) of the main isotopomer (A=202 069, B=15 282, C=14 840), determined by applying a least-squares analysis to the presently available data set, are in excellent agreement with those predicted by quantum-chemical calculations (A=202 136, B=15 279, C=14 840). Our theoretical treatment also derived the following barrier heights against internal rotation in HSOH (when in the cis and trans configurations) to be V(cis) approximately equal to 2216 cm(-1) and V(trans) approximately equal to 1579 cm(-1). The internal rotational motion results in detectable torsional splittings that are dependent on the angular momentum quantum numbers J and K(a).
气相氧二硫烷（HSOH）是著名分子过氧化氢（HOOH）和二硫烷（HSSH）之间缺失的环节，它是通过二叔丁基亚砜的快速真空热解合成的。利用质谱法，已针对HSOH的形成对热解条件进行了优化。借助高水平量子化学计算，对热解产物进行微波光谱研究，首次测量了HSOH的旋转扭转光谱。我们总共在64吉赫兹至1.9太赫兹的频率范围内测量了约600条旋转扭转光谱线，并将其中约470条归属于处于基态扭转状态的HSOH的旋转扭转光谱。600条谱线中约120条来自同位素异构体H(34)SOH。HSOH分子显示出强c型跃迁和稍弱的b型跃迁，表明其为非平面扭曲链结构，类似于类似分子HOOH和HSSH。通过对现有数据集进行最小二乘法分析确定的主要同位素异构体的旋转常数（兆赫兹）（A = 202069，B = 15282，C = 14840）与量子化学计算预测的值（A = 202136，B = 15279，C = 14840）非常吻合。我们的理论处理还得出，HSOH（处于顺式和反式构型时）内部旋转的以下势垒高度为V(顺式)约等于2216厘米^(-1)，V(反式)约等于1579厘米^(-1)。内部旋转运动会导致可检测到的扭转分裂，其取决于角动量量子数J和K(a)。
