Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States.
J Am Chem Soc. 2017 May 31;139(21):7144-7147. doi: 10.1021/jacs.7b02692. Epub 2017 May 22.
We report a large kinetic isotope effect at 298 K, k/k ≈ 150, associated with an intramolecular 1,5-hydrogen atom transfer (1,5-HAT) in the decay of a PEGylated carbazyl (aminyl) radical in solution. The experimental observations surprisingly combine the hallmarks of tunneling, including large KIEs and unusual activation parameters, with linear Arrhenius and Eyring plots over an exceptionally wide temperature range of 116 K.
我们报道了在 298 K 下的一个大动力学同位素效应，k/k ≈ 150，与在溶液中聚乙二醇化咔唑（氨）自由基的衰减过程中的分子内 1,5-氢原子转移（1,5-HAT）有关。实验观察结果出人意料地将隧道效应的特征结合在一起，包括大的 KIE 和不寻常的活化参数，以及在异常宽的 116 K 温度范围内的线性阿仑尼乌斯和艾林图。
