Ricochet inter-ring haptotropic rearrangement of σ-methyl-(η5-indenyl) chromium tricarbonyls. Experimental kinetic and theoretical DFT study
作者:O.I. Trifonova、E.A. Ochertyanova、N.G. Akhmedov、V.A. Roznyatovsky、D.N. Laikov、N.A. Ustynyuk、Yu.A. Ustynyuk
DOI:10.1016/s0020-1693(98)00258-8
日期:1998.10
6±0.2 cal K −1 mol −1 ). ( IV ) undergoes further irreversible isomerization at 60–120° into ( ν 6 -3-methylindene) chromium tricarbonyl ( V ) with a higher activation barrier ( ΔG # =28.5±0.1 kcal mol −1 ) via two consecutive [1,5]-sigmatropic hydrogen shifts. The mechanisms of both rearrangements have been studied in detail using density functional theory (DFT) calculations with extended basis sets
摘要在30–60°C的C 6 D 6溶液中,σ-甲基-(η5-茚基)三羰基铬(III)定量重排为η6 -1-内-甲基茚基)三羰基铬(IV)。在(III)中茚基配位体2或3的甲基附着对该弹跳的环间触觉重排的激活参数没有影响(ΔG#= 23.6 kcal mol -1;ΔH#= 18.9±0.2 kcal mol- 1;ΔS#= -18.6±0.2cal K -1 mol -1)。(IV)在60–120°处通过两个连续的[1,5]进一步不可逆地异构化为具有较高活化能垒(ΔG#= 28.5±0.1 kcal mol -1)的(ν6 -3-甲基茚)三羰基铬(V) σ-氢转移。两种重排的机制已使用扩展泛集的密度泛函理论(DFT)计算进行了详细研究。计算表明,重排(III)→(IV)分两个步骤进行。甲基从铬迁移到茚基配体的1位是决定速率的步骤,导致形成16电子中间体(VII)。计算出的活化势垒(E a