BH_2^+与C_2H_2反应势能面的量子化学研究  

Quantum-chemical Investigation on the Potential Energy Surface of the Reaction of BH_2^+ with C_2H_2

作　　者：屈正旺[1] 李泽生[1] 丁益宏 孙家钟 

机构地区：[1]吉林大学理论化学研究所理论化学计算国家重点实验室,长春130023

出　　处：《高等学校化学学报》2001年第10期1711-1714,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金 (批准号 :2 973310 0 ;2 9892 16 8)资助

摘　　要：用 B3LYP/6-31 1 G( d,p)密度泛函方法和高级电子相关的 CCSD( T) /6-31 1 G( 2 df,p)偶合簇法研究BH+ 2 与 C2 H2 反应势能面 .结果表明 :该势能面上存在 ( a) H2 B+· C2 H2 ,( b) HBCHCH2 + ,( c) H2 BCCH+ 2 和( d) H2 · BHCCH+ 四种异构体 ,其中 ( b)能量最低且在动力学上最稳定 ,( a) ,( c)和 ( d)在动力学上均不稳定 ;BH+ 2 通过对 C2 H2 的分步亲电加成以及随后的氢迁移和 H2 消除等反应形成离解产物 HBCCH+ +H2 ,该反应不需要活化能且大量放热 .计算结果有助于深入了解 BH+ 2The potential energy surface of the ion\|molecular reaction of BH\++\-2 with C\-2H\-2 in gas\|phase has been investigated theoretically by using the B3LYP/6\|311G(\%d,p\%) and the high\|level electron\|correlation CCSD(T)/6\|311G(2\%df,p\%) single\|point levels. Four isomers H\-2B\++·C\-2H\-2(a), HBCHCH\++\-2(b), H\-2BCCH\++\-2(c) and H\-2·BHCCH\++(d) are found, among which isomer (b) is the most stable both thermodynamically and kinetically while isomers (a), (c) and (d) are kinetically unstable. The mechanism for the reaction BH\++\-2+C\-2H\-2→HBCCH\+++H\-2 is discussed based on the potential energy surface. It is shown that BH\++\-2 may carry out an electrophilic addition towards C\-2H\-2 followed by multi\|step H\|shifts and final H\-2\|elimination to form product HBCCH\+++H\-2, the total reaction is barrier\|free and largely exothermic. The calculated results presented in this paper may be helpful for understanding the chemical behavior of electron\|deficient borohydride cations such as BH\++\-2.

关 键 词：硼氢正离子 反应势能面 反应机理 乙炔 量子化学 密度泛函 

分 类 号：O613.81[理学—无机化学] O643.12[理学—化学]