Theoretical study on the isomerization behavior between α,β-unsaturated acyl radicals and α-ketenyl radicals
Theoretical study on the isomerization behavior between α,β-unsaturated acyl radicals and α-ketenyl radicals
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DOI：
10.1021/jo047868i
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发表时间：
2005-03
影响因子：
3.6
通讯作者：
H. Matsubara;I. Ryu;C. Schiesser
中科院分区：
文献类型：
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作者：
H. Matsubara;I. Ryu;C. Schiesser
采用6- 311 G **，cc-pVDZ，aug-cc-pVDZ，DZP基组，QCISD，CCSD（T）和UHF两种电子关联方法，密度泛函方法（BHandHLYP，B3 LYP），从头算方法预测了α，β-不饱和酰基和α-烯酮基以异构体形式存在.在CCSD（T）/cc-pVDZ//BHandHLY/cc-pVDZ理论水平下，计算出s-反式丙烯酰基和s-反式巴豆酰基异构化为烯酮甲基和1-烯酮乙基的能垒分别为15.1和17.7−21.7 kJ mol-1。在CCSD（T）/DZP//BHandHLYP/DZP计算中，涉及甲硅烷基、甲锗烷基和甲锡烷基的s-反式异构体的反应也得到了类似的结果，其能垒（ΔE）分别为12.2−12.4、13.1−13.9和12.9−18.2 kJ mol-1。这些结果表明，α，β-不饱和酰基自由基和α-烯酮自由基不是标准形式，而是可以快速相互转化的异构体。
Ab initio calculations using 6-311G**, cc-pVDZ, aug-cc-pVDZ, and a (valence) double-ζ pseudopotential (DZP) basis set, with (QCISD, CCSD(T)) and without (UHF) the inclusion of electron correlation, and density functional methods (BHandHLYP, B3LYP) predict that α,β-unsaturated acyl radicals and α-ketenyl radicals exist as isomers. At the CCSD(T)/cc-pVDZ//BHandHLY/cc-pVDZ level of theory, energy barriers of 15.1 and 17.7−21.7 kJ mol-1 are calculated for the isomerization of s-trans-propenoyl and s-trans-crotonoyl radical to ketenylmethyl and 1-ketenylethyl radical, respectively. Similar results are obtained for the reactions of s-trans isomers involving silyl, germyl, and stannyl groups with energy barriers (ΔE⧧) of 12.2−12.4, 13.1−13.9, and 12.9−18.2 kJ mol-1 at the CCSD(T)/DZP//BHandHLYP/DZP calculation, respectively. These results suggest that α,β-unsaturated acyl radicals and α-ketenyl radicals are not canonical forms but are isomeric species that can rapidly interconvert.