Singlet Oxygen's Potential Role as a Nonoxidative Facilitator of Disulfide S–S Bond Rotation †
Singlet Oxygen's Potential Role as a Nonoxidative Facilitator of Disulfide S–S Bond Rotation †
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DOI：
10.1111/php.13727
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发表时间：
2022-09
影响因子：
3.3
通讯作者：
O. Turque;Ryan M O'Connor;A. Greer
中科院分区：
文献类型：
--
作者：
O. Turque;Ryan M O'Connor;A. Greer
研究了单线态氧可能介导二硫化物构象柔性增加的作用。密度泛函理论（DFT）计算表明，1，2-二甲基二硫烷的单线态氧化产生过氧中间体。与未氧化的1，2-二甲基二硫烷相比，该中间体具有更长的S-S键距和更平的扭转角θ（C-S-S-C）。延长的S-S键使得在0° < θ < 210°的圆区域内围绕扭转角的旋转变得容易，这比二硫烷的能量低约5 kcal mol−1。过氧中间体具有nO → σS-S和nO → σ*S-S相互作用，其稳定S-O键但使S-S键不稳定，这与二硫烷S-S键中稳定nS → σ*S-S超共轭效应形成对比。随后O2从二硫烷过氧中间体的离开使人想起过氧中间体，其也排出O2，但促进芪、己二烯、花青和胡萝卜素的顺-反异构化。“非氧化”1 O2与各种键类型的相互作用目前未得到充分重视。我们希望提高人们对这些相互作用如何有助于阐明分子扭曲起源的认识。
The role of singlet oxygen potentially mediating increased conformational flexibility of a disulfide was investigated. Density functional theory (DFT) calculations indicate that the singlet oxygenation of 1,2‐dimethyldisulfane produces a peroxy intermediate. This intermediate adopts a structure with a longer S–S bond distance and a more planar torsional angle θ (C–S–S–C) compared with the nonoxygenated 1,2‐dimethyldisulfane. The lengthened S–S bond enables a facile rotation about the torsional angle in the semicircle region 0° < θ < 210°, that is ~5 kcal mol−1 lower in energy than the disulfane. The peroxy intermediate bears nO → σS–S and nO → σ*S–S interactions that stabilize the S–O bond but destabilize the S–S bond, which contrasts with stabilizing nS → σ*S–S hyperconjugative effects in the disulfane S–S bond. Subsequent departure of O2 from the disulfane peroxy intermediate is reminiscent of peroxy intermediates which also expel O2, yet facilitate cis‐trans isomerizations of stilbenes, hexadienes, cyanines, and carotenes. “Non‐oxidative” 1O2 interactions with a variety of bond types are currently underappreciated. We hope to raise awareness of how these interactions can help elucidate the origins of molecular twisting.