Kinetics and Mechanism of 4,4-Dicyano 5-Ethyl 1,5-Heptadiene Reaction in Gas and Solution Phase; Theoretical Approach

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Omidi, Masoume | 2010

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 41111 (03)
University: Sharif University of Technology
Department: Chemistry
Advisor(s): Gholami, Mohammad Reza; Sajjadi, Ali Akbar
Abstract:
Kinetics and mechanism of 4,4-dicyano-5-ethyl-1,5-heptadiene rearrangement reaction, a pericyclic type reaction, were studied with ab initio calculations in gas and solution phases. This reaction is one of the cope rearrangement in which secondary kinetic isotope effect is observed. Theoretical study on these reactions showed that probability of radicalic mechanism is inconsiderable and reaction proceeds through out a concerted mechanism with cyclic transition state. Isotope effect was studied by replacement of H1, H2 and H4,H5 with deuterium. The isotope effect data confirmed the concerted mechanism. Solvent effects on this reaction were studied by CPCM model. Solvation energies at B3LYP/6-31G level of theory for 2.02, 20.7, 24.5, 32.7, 37.5, 46.7, 60, 80.1 dielectric constants were obtained using CPCM model. The results showed that dielectric constant of solvent have no effect on reaction rate
Keywords:
Ab Initio Calculation ; Cope Rearrangement ; Conductor Pollarized Continuum Model (CPCM) ; Secondary Kinetic Isotope Effect

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