63035-87-0Relevant academic research and scientific papers
Homolytic Rearrangements of Ketenimines to Nitriles: Employments of Hammett Dual Parameters
Kim, Sung Soo,Liu, Bo,Park, Chul Hyun,Lee, Kwang Ho
, p. 1571 - 1573 (1998)
The thermal isomerizations of ketenimines to nitriles involve a "homolytic" transition state (TS) as the major contributor to the structure of the TS. The rates have been fitted to Hammett dual correlations. The magnitudes of |ρ/ρ| represent the relative weights in the TS assuming homolytic character.
Thermal isomerizations of ketenimines to nitriles: Evaluations of sigma- dot (σ·) constants for spin-delocalizations
Kim, Sung Soo,Zhu, Yu,Lee, Kwang Ho
, p. 2919 - 2923 (2007/10/03)
Rate constants (k(Y)) of the isomerizations of 11 diphenyl N- (substituted benzyl) ketenimines were measured at 40, 50, 60, and 70°C. Activation parameters ΔH((+))(Y) and ΔS((+))(Y) were obtained using the Eyring equation. The relative rates (k(Y)/k(H)) were fitted into Hammett single correlations (log k(Y)/k(H) = ρσ and log k(Y)/k(H) = ρ·σ·). The single correlations have been compared with Hammett dual correlations (log k(Y)/k(H) = ρσ + ρ·σ·). Separate treatments of para and meta substituents yielded even better correlations. Para substituents control the rates through spin-delocalizations and inductive effects. The former outweighs the latter when the latter exerts a modest but distinct influence on the rates. On the other hand, inductive effects are the 'major' or the sole interactions triggered by meta substituents.
