Spectroscopic characterization and photochemistry of the vinylsulfinyl radical.
Spectroscopic characterization and photochemistry of the vinylsulfinyl radical.
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DOI：
10.1039/d1cp02584h
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发表时间：
2021-07
期刊：
影响因子：
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通讯作者：
Zhuang Wu;Lina Wang;Bo Lu;A. Eckhardt;P. Schreiner;Xiaoqing Zeng
中科院分区：
文献类型：
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作者：
Zhuang Wu;Lina Wang;Bo Lu;A. Eckhardt;P. Schreiner;Xiaoqing Zeng
本文报道了亚砜CH_2 [双键，长为m-破折号] C（H）S（O）CF_3在高真空快速热解（HVFP）条件下，在气相中生成最简单的α，β-不饱和亚磺酰基自由基CH_2 [双键，长为m-破折号]C（H）SO_3。八百度。在低温基质（N2、Ne和Ar）中分离出CH 2 [双键，长度为m-破折号]C（H）SO的两种平面顺式和反式构象，并用IR和UV/维斯光谱进行表征。除了光诱导的顺反构象转换外，CH_2 [双键，长度为m-破折号]C（H）SO还表现出复杂的光化学反应。在用紫光LED（400 nm）照射时，CH 2 [双键，长度为m-破折号]C（H）SO stec异构化为新的自由基CH 3SCO stec、stec CH 2SC（O）H和stec CH 2C（O）SH，同时解离为笼状分子络合物CH 3S stec CO。随后的紫外激光（266 nm）照射导致裂解为stecCH 3/OCS，并额外形成难以捉摸的羰基CH 3C（O）S stec，其在进一步的紫外光照射（365 nm）后重排为stecCH 2C（O）SH。CH 2 [双键，长为m-dash]C（H）SO的两种构象的振动数据和成键分析表明，它们都是不成对电子与邻位π（C[双键，长为m-dash]C）键共轭的松弛自由基，导致stecCH 2-C（H）SO的正则共振形式的显著贡献。在CCSD（T）-F12 a/aug-cc-pVTZ//B3 LYP/6-311++G（3df，3 pd）水平上，根据观察到的中间体沿着计算得到的势能分布，讨论了CH 2 [双键，长度为m-dash]C（H）SO stec异构化的机理.
The simplest α,β-unsaturated sulfinyl radical CH2[double bond, length as m-dash]C(H)SO˙ has been generated in the gas phase by high-vacuum flash pyrolysis (HVFP) of sulfoxide CH2[double bond, length as m-dash]C(H)S(O)CF3 at ca. 800 °C. Two planar cis and trans conformers of CH2[double bond, length as m-dash]C(H)SO˙ were isolated in cryogenic matrixes (N2, Ne, and Ar) and characterized with IR and UV/Vis spectroscopy. In addition to the photo-induced cis ⇋ trans conformational interconversion, CH2[double bond, length as m-dash]C(H)SO˙ displays complex photochemistry. Upon irradiation with a purple light LED (400 nm), CH2[double bond, length as m-dash]C(H)SO˙ isomerizes to novel radicals CH3SCO˙, ˙CH2SC(O)H, and ˙CH2C(O)SH with concomitant dissociation to a caged molecular complex CH3S˙CO. Subsequent UV-laser (266 nm) irradiation causes fragmentation to ˙CH3/OCS and additional formation of an elusive carbonyl radical CH3C(O)S˙, which rearranges to ˙CH2C(O)SH upon further UV-light irradiation (365 nm). The vibrational data and bonding analysis of the two conformers of CH2[double bond, length as m-dash]C(H)SO˙ suggest that both are floppy radicals in which the unpaired electron conjugates with the vicinal π(C[double bond, length as m-dash]C) bond, leading to significant contribution of the canonical resonance form of ˙CH2-C(H)SO. The mechanism for the isomerization of CH2[double bond, length as m-dash]C(H)SO˙ is discussed based on the observed intermediates along with a computed potential energy profile at the CCSD(T)-F12a/aug-cc-pVTZ//B3LYP/6-311++G(3df,3pd) level of theory.