论文部分内容阅读
本文认为零价镍[Ni(0)]、配位零价镍[LNi(0)]催化丁二烯环化齐聚反应中间体分别为Ni(C_4H_6)_3(Ⅰ),LNi(C_4H_6)_3(Ⅱ),采用EHMO法对中间体(Ⅰ)和(Ⅱ)进行了计算。通过集居数分析得出两种中间体都以σ—π键结合,并且中间体(Ⅰ)的σ—π键的强度大于(Ⅱ),再根据电荷密度的分析,得出中间体(Ⅰ)的稳定性大于(Ⅱ)。中间体(Ⅰ)与(Ⅱ)结构的不同,稳定性的不同,决定看催化剂Ni(0)、LNi(0)的活性与选择的不同。
In this paper, we believe that the intermediates of cyclization and oligomerization of butadiene catalyzed by zero-valent nickel [Ni (0)] and coordinated zero-valent nickel [LNi (0)] are Ni (C_4H_6) _3 (Ⅰ), LNi (C_4H_6) _3 (Ⅱ), the intermediates (Ⅰ) and (Ⅱ) were calculated by EHMO method. According to the analysis of population density, it was found that both intermediates were bound by σ-π bond, and the σ-π bond strength of intermediate (Ⅰ) was greater than (Ⅱ). According to the analysis of charge density, ) Is more stable than (II). The difference of the structure and the stability of the intermediates (I) and (II) determines the difference in the activity and selectivity of the catalysts Ni (0) and LNi (0).