Kim Jong Chan, Kim Kyoung Hoon, Jung Jaehoon, Han Young-Kyu
Computational Chemistry Laboratory, Corporate R&D, LG Chemical Ltd., Research Park, 104-1 Moonji-dong, Yusung-gu, Daejeon 305-380, Republic of Korea.
J Comput Chem. 2008 Jul 30;29(10):1626-31. doi: 10.1002/jcc.20921.
We have investigated the transition-state structures and reaction mechanisms for the dissociative chemisorption reactions of HI, I(2), and CH(3)I on the magic cluster Al(-) (13). The HI, I(2), and CH(3)I molecules approach Al(-) (13) with an end-on orientation rather than a side-on orientation because of the more effective orbital overlap in the end-on orientation. The reactions of Al(-) (13) with HI and I(2) would produce Al(13)HI(-) and Al(13)I(2) (-), respectively, because of large exothermic energy changes and relatively small activation energies. The reaction of Al(-) (13) with CH(3)I is unlikely to take place because of the low mobility of CH(3) on Al(-) (13) and the high activation barrier for the S(N)2-type reaction. The dissociative chemisorption reactions are preferred thermodynamically to the abstractive chemisorption reactions.
我们研究了HI、I₂和CH₃I在神奇团簇Al⁻(13)上的解离化学吸附反应的过渡态结构和反应机理。由于端对端取向中轨道重叠更有效，HI、I₂和CH₃I分子以端对端取向而非侧对侧取向接近Al⁻(13)。Al⁻(13)与HI和I₂的反应分别会产生Al₁₃HI⁻和Al₁₃I₂⁻，这是因为有大量的放热能量变化和相对较小的活化能。Al⁻(13)与CH₃I的反应不太可能发生，因为CH₃在Al⁻(13)上的迁移率低以及SN2型反应的活化能垒高。解离化学吸附反应在热力学上比抽取化学吸附反应更有利。
