Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Angew Chem Int Ed Engl. 2017 Jun 26;56(27):7740-7744. doi: 10.1002/anie.201702722. Epub 2017 May 4.
Criegee intermediates have implications as key intermediates in atmospheric, organic, and enzymatic reactions. However, their chemistry in aqueous environments is relatively unexplored. Herein, Born-Oppenheimer molecular dynamics (BOMD) simulations examine the dynamic behavior of syn- and anti-CH CHOO at the air-water interface. They show that unlike the simplest Criegee intermediate (CH OO), both syn- and anti-CH CHOO remain inert towards reaction with water. The unexpected high stability of C Criegee intermediates is due to the presence of a hydrophobic methyl substituent on the Criegee carbon that lowers the proton transfer ability and inhibits the formation of a pre-reaction complex for the Criegee-water reaction. The simulation of the larger Criegee intermediates, (CH ) COO, syn- and anti-CH C(CH )C(H)OO on the water droplet surface suggests that strongly hydrophobic substituents determine the reactivity of Criegee intermediates at the air-water interface.
Criegee 中间体作为大气、有机和酶反应中的关键中间体具有重要意义。然而，它们在水相环境中的化学性质还相对未知。本文通过 Born-Oppenheimer 分子动力学（BOMD）模拟研究了 syn- 和 anti-CH CHOO 在气-液界面上的动态行为。结果表明，与最简单的 Criegee 中间体（CH OO）不同，syn- 和 anti-CH CHOO 均对与水的反应表现出惰性。Criegee 中间体出人意料的高稳定性归因于 Criegee 碳上存在疏水性甲基取代基，这降低了质子转移能力并抑制了 Criegee-水反应的预反应络合物的形成。在水滴表面上模拟较大的 Criegee 中间体（CH ）COO、syn- 和 anti-CH C(CH )C(H)OO 表明，强疏水性取代基决定了 Criegee 中间体在气-液界面上的反应性。
