科研之友
微信
新浪微博
Facebook
分享链接
摘要
Two competitive reaction mechanisms for the gas-phase chemical transformation of singlet chlorocarbene into chloromethanol in the presence of one and two water molecules are examined in detail. An analysis of bond orders and bond order derivatives as well as of properties of bond critical points in the electron densities along the intrinsic reaction coordinates (IRCs for intermediates -%26gt; transition state (TS) -%26gt; products) suggests that, from the perspective of bond breaking/ formation, both reactions should be considered to be highly nonsynchronous, concerted processes. Both transition states are early, resembling the intermediates, yielding rate constants whose magnitudes are mostly influenced by structural changes and to a lesser degree by bond breaking/formation. For the case of one water molecule, most of the energy in the reactants region of the IRC is used for structural changes, while the transition state region encompasses the majority of electron activity, except for the formation of the C-O bond, which extends well into the products region. In the case of two water molecules, very little electron flux and comparatively less work required for structural changes is noticed in the reactants region, leading to an earlier transition state and therefore to a smaller activation energy and to a larger rate constant This, together with evidence gathered from other sources, allows us to provide plausible explanations for the observed difference in rate constants.
- 出版日期2013-3-7
