Stereodifferentiation in the Decay of Triplets and Biradicals Involved in Intramolecular Hydrogen Transfer from Phenols or Indoles to π,π* Aromatic Ketones
作者:Julia Pérez-Prieto、Agustín Lahoz、Francisco Boscá、Ramón Martinez-Mañez、Miguel A. Miranda
DOI:10.1021/jo0356199
日期:2004.1.1
Laser flash photolysis studies on (R,S) and (S,S) diastereoisomers of the bichromophoric compounds 1−6 have been used to investigate the possible chiral discrimination in the quenching of triplet excited ketones, resulting in formal hydrogen abstraction. Deuterium isotopic effects show that triplet deactivation in these bichromophores is dominated by hydrogen atom transfer. A remarkable stereodifferentiation
上(激光闪光光解的研究- [R ,小号)和(小号,小号)的bichromophoric化合物的非对映体1 - 6已被用于研究在三重激发酮的淬火可能手性识别,导致正式夺氢。氘同位素效应表明,这些双色团中的三重态失活主要由氢原子转移引起。一个显着的stereodifferentiation在的酮三元组的分子内淬发现1 - 3和5通过在甲醇或乙腈中的酚或吲哚部分作为溶剂。这表明存在氢转移的特定结构要求。另一方面,所产生的双基的寿命显示出很大的溶剂依赖性。溶剂化似乎减慢了它们向起始酮的还原。对于双自由基寿命观察到的相当大的立体分化表明,当两个自由基末端的接近变得更容易时,双自由基衰变的动力学更快。