Abstract
We present here a detailed analysis of benzyl isocyanide isomerization as a test case for the ability of different theoretical methods to treat changes in internal rotational degrees of freedom during a reaction. In this reaction, the phenyl rotates freely in the reactant, but has hindered rotation at the transition state; this yields a negative contribution to the reaction entropy. Free energy of activation, internal energy of activation, and entropy of activation were quantified using both thermodynamic integration and harmonic frequency analysis. Compared with experiment, thermodynamic integration generated more accurate activation parameters than the harmonic frequency analysis. A hindered rotor model was also applied to retrieve thermodynamic properties of phenyl rotation at the reactant and at the transition state. The results from this hindered rotor calculation were used to improve the results from the harmonic frequency analysis as well as to verify that the decrease in entropy from the phenyl rotation hindered at the transition state is a major contributor to the entropy of activation seen experimentally in this reaction.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
