Cyclopropylcarbinyl ring opening as mechanistic probe for differentiation between the singlet and triplet spin states of trimethylenemethane diradicals (non-Kekule species)
作者:Waldemar Adam、Ralf Finzel
DOI:10.1021/ja00038a018
日期:1992.6
The cyclopropylcarbinyl rearrangement of the non-Kekule 2-alkylidene-1,3-cyclopentanediyl diradical (S-2b and T-2b), generated by thermal and direct and triplet-sensitized photochemical denitrogenation of the corresponding azoalkane 1b, was explored. While in the triplet-sensitized photolysis at moderate temperatures no cyclopropylcarbinyl rearrangement took place, in the singlet manifold (thermolysis
探索了非 Kekule 2-亚烷基-1,3-环戊二基双自由基(S-2b 和 T-2b)的环丙基羰基重排,由相应的偶氮烷 1b 的热和直接和三线态敏化光化学脱氮产生。虽然在中等温度下的三线态敏化光解中没有发生环丙基羰基重排,但在单线态歧管(热解和直接光解)中观察到重排的烃 3。重排烃 3 的量随着温度的升高而增加,并且从温度依赖性来看,活化能约为 开环估计为 5 kcal/mol