Free electron transfer mirrors rotational conformers of substituted aromatics: Reaction of benzyltrimethylsilanes with n-butyl chloride parent radical cations
作者:Ortwin Brede、Ralf Hermann、Sergej Naumov、Antonios K. Zarkadis、Gerasimos P. Perdikomatis、Michael G. Siskos
DOI:10.1039/b402052a
日期:——
chloride parent radical cations, the singlet ground state conformers are converted into two kinds of radical cations. The cations tending to the planar type are stable whereas those of the twisted type dissociate immediately into benzyl type radicals (p-R3–C6H4–C˙R1R2) and trimethylsilyl cations. The above mentioned product pattern and quantum-chemical calculations on characteristic parameters of the ground
芳环的较大取代基的旋转运动伴随着最高占据分子轨道的电子密度波动。对于苄基三甲基硅烷 p-R3–C6H4––CR1R2(SiMe3) [R3 = H,PhCO; R1, R2 = H,H; H,我; 我,我;H,Ph; Ph,Ph] 含甲硅烷基的取代基在芳族部分和苄基碳之间的轴上旋转,如式中所示。在此轮换过程中,通过了各种构象异构体。为简单起见,我们将这种多样性简化为两种(极端)边界结构,一种是取代基与芳环在同一平面内(瞬态),另一种是取代基扭曲 90°(稳定结构)。在从构象异构体混合物到正丁基氯母体自由基阳离子的非常快速且不受阻碍的电子转移中,单线态基态构象异构体被转化为两种自由基阳离子。倾向于平面型的阳离子是稳定的,而扭曲型的阳离子则立即解离成苄基型自由基(p-R3-C6H4-C˙R1R2)和三甲基甲硅烷基阳离子。上述关于基态构象异构体和产物阳离子的特征参数的产物模式和量子化学计算表明,