A combined experimental and theoretical study was conducted to investigate the isomerization of 2-methyl-3-butenenitrile (2M3BN) to 3-pentenenitrile (3PN) and to 2-methyl-2-butenenitrile (2M2BN) catalyzed by nickel diphosphine complexes. Ni(1,4-bis(diphenylphosphino)butane) (dppb) was identified as the most reactive catalyst among the complexes that we examined experimentally. Quantum mechanics (density functional theory) was then used to study the two isomerization mechanisms catalyzed by this complex. We find that for the 2M3BN → 3PN isomerization, the reaction is initiated with CCN bond cleavage, followed by an allyl direct rotation and CCN bond reformation. For the 2M3BN → 2M2BN isomerization, the most energetically favorable pathway begins with CH bond activation, followed by a π-σ-σ-π allyl rearrangement and CH bond reformation. Our proposed mechanism for the 2M3BN → 2M2BN isomerization is slightly different (yet energetically more favorable) than that described in previous studies, where it has been suggested that 2M2BN is obtained through a π-σ-σ allyl rearrangement rather than a π-σ-σ-π type rearrangement. Additionally, we investigated the effect of Lewis acids in the 2M3BN → 3PN isomerization, which has been shown in most experiments to attenuate the reaction. Notably, our calculations indicated that ZnCl₂, which is used as a model Lewis acid, actually reduces the barriers for all elementary steps. However, the effective kinetic barrier for the isomerization increases from 23.7 (without ZnCl₂) to 24.0 kcal/mol because of the formation of a very stable Ni(π-allyl) (CNZnCl₂) intermediate, causing a decrease in the reaction rate. This theoretical result was further confirmed by our own experiments.

进行了组合的实验和理论研究，以研究二膦镍配合物将2-甲基-3-丁烯腈（2M3BN）异构化为3-戊烯腈（3PN）和2-甲基-2-丁烯腈（2M2BN）。Ni（1,4-双（二苯基膦基）丁烷）（dppb）被确定为我们实验检测的络合物中最具反应性的催化剂。然后，使用量子力学（密度泛函理论）研究了该复合物催化的两种异构化机理。我们发现，对于2M3BN→3PN异构化，该反应是通过C CN键裂解引发的，然后是烯丙基直接旋转和C CN键重整。对于2M3BN→2M2BN异构化，最有利于能量的途径始于CH键活化，然后进行π-σ-σ-π烯丙基重排和C H键重整。我们提出的2M3BN→2M2BN异构化的机制与以前的研究稍有不同（但在能量上更有利），以前的研究表明2M2BN是通过π-σ-σ烯丙基重排而不是π-σ-获得的。 σ-π型重排。此外，我们研究了路易斯酸在2M3BN→3PN异构化中的作用，这在大多数实验中已表明可减弱反应。值得注意的是，我们的计算表明，用作模型路易斯酸的ZnCl ₂实际上减少了所有基本步骤的势垒。但是，异构化的有效动力学势垒从23.7（没有ZnCl ₂）至24.0 kcal / mol，因为形成了非常稳定的Ni（π-烯丙基）（CN ZnCl ₂）中间体，导致反应速率降低。我们自己的实验进一步证实了这一理论结果。