高等学校化学学报 ›› 1996, Vol. 17 ›› Issue (11): 1779.

• 研究简报 • 上一篇    下一篇

M++BrCN─→MCN++Br气相反应的从头算研究

朱荣顺, 戴树珊   

  1. 云南大学化学系, 昆明, 650091
  • 收稿日期:1995-11-22 出版日期:1996-11-24 发布日期:1996-11-24
  • 通讯作者: 朱荣顺,男,27岁,博士研究生.
  • 作者简介:朱荣顺,男,27岁,博士研究生.
  • 基金资助:

    国家自然科学基金

Ab Initio Study on the Gas-phase Reaction of M++BrCN→MCN++Br

ZHU Rong-Shun, DAI Shu-Shan   

  1. Department of Chemistry, Yunnan University, Kunming, 650091
  • Received:1995-11-22 Online:1996-11-24 Published:1996-11-24

关键词: 气相反应, 过渡金属阳离子, 溴化氰, 从头算, 相对论赝势

Abstract: Ab initio quantum chemical calculations with averaged relativistic effective potentials(AREP),including the effects of electron correlation,are performed on the reactions, M++BrCN→MCN++Br,Where M+ is the first-row transition-metal singly charged cation.The highest barrier for the reaction is found for the Mn+(485.54 kJ/mol),which is due to the large loss of exchange energy upon bond formation and large repulsion of the 4s electrons.According to the calculated barrier height,the reactivities are in agreement with experimental trends:V>Mn,Fe;Co>Cr.However,contrary to the experimental trends Sc>Ti.In our study,the transition state for scandium cation is considerably higher than that for titanium cation,because titanium cation is in the less repulsive state 4F(d2s1)since it has lower s-population,and therefore it has lower barrier.We can explain why the reaction extent of the first row metal cations with cyanogen bromide was only a few percent,one of the main reasons is that the barrier height is too high.

Key words: Gas-phase reaction, Transition metal cations, Cyanogen bromide, Ab initio study, Relativistic effective potential

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