Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, USA.
Chemistry. 2023 Jun 7;29(32):e202203906. doi: 10.1002/chem.202203906. Epub 2023 Apr 27.
The reactions of elemental sulfur (S ) and polysulfides with nucleophiles are relevant to organic synthesis, materials science and biochemistry, but the mechanisms by which they operate are still unknown due to the inherent thermodynamic and kinetic instability of polysulfide intermediates. Using Density Functional Theory (DFT) calculations at the ωB97X-D/aug-cc-pV(T+d)Z/SMD(MeCN) // ωB97X-D/aug-cc-pVDZ/SMD(MeCN) level of theory, we studied the mechanisms behind the reaction of elemental sulfur and polysulfides with cyanide and phosphines, which quantitatively generate the monosulfide products thiocyanate and phosphine sulfides, respectively. All plausible pathways including nucleophilic decomposition, unimolecular decomposition, scrambling reactions, and attack on thiosulfoxides, have been considered to provide the first comprehensive mechanistic picture for this class of reactions. Overall, intramolecular cyclization is identified as the most favorable decomposition pathway for long polysulfides. For short polysulfides, a mixture of unimolecular decomposition, nucleophilic attack, and scrambling pathways can be expected.
元素硫（S）和多硫化物与亲核试剂的反应与有机合成、材料科学和生物化学有关，但由于多硫化物中间体固有的热力学和动力学不稳定性，它们的作用机制仍然未知。我们使用密度泛函理论（DFT）计算，在 ωB97X-D/aug-cc-pV(T+d)Z/SMD(MeCN) // ωB97X-D/aug-cc-pVDZ/SMD(MeCN)理论水平上，研究了元素硫和多硫化物与氰化物和膦的反应机制，这两种反应分别定量生成单硫化物产物硫氰酸盐和硫代膦氧化物。我们考虑了所有可能的途径，包括亲核分解、单分子分解、 scrambling 反应和对亚砜的攻击，为这一类反应提供了第一个全面的机理图像。总的来说，分子内环化被确定为长多硫化物最有利的分解途径。对于短多硫化物，可以预期存在单分子分解、亲核攻击和 scrambling 途径的混合物。
