Transition from synchronous to asynchronous mechanisms in 1,3-dipolar cycloadditions: a polarizability perspective
César Barrales-Martínez1,2, Rocío Durán3, Pablo Jaque4,5
1Instituto de Investigación Interdisciplinaria (I3), Vicerrectoría Académica, Universidad de Talca, Campus Talca, Talca, Chile. cesar.barrales@utalca.cl.
Journal of Molecular Modeling
|September 30, 2024
Summary
This study reveals how reaction mechanisms in 1,3-dipolar cycloadditions become asynchronous. Increased asynchronicity decouples polarizabilities and shifts their maximum along the reaction path.
Area of Science:
- Chemical Kinetics
- Computational Chemistry
- Quantum Chemistry
Background:
- Investigates energetic and polarizability characteristics of 1,3-dipolar cycloadditions.
- Focuses on the transition from synchronous to asynchronous reaction mechanisms.
Purpose of the Study:
- Analyze synchronicity and polarizability changes during 1,3-dipolar cycloaddition reactions.
- Correlate reaction mechanism asynchronicity with polarizability evolution.
Main Methods:
- Employs Density Functional Theory (DFT) calculations.
- Utilizes the B3LYP/6-311+G(d,p)//B3LYP/6-31G(d,p) level of theory.
- Calculates polarizability along the intrinsic reaction coordinate (IRC).
Main Results:
- Synchronicity decreases with increasing cyano groups, indicating decoupled bond evolution.
- Isotropic polarizability peaks at the transition state; anisotropy shifts toward products asynchronicity increases.
- Parallel polarizability component evolution correlates with energy changes and indicates mechanism synchronicity.
Conclusions:
- Asynchronous 1,3-dipolar cycloadditions show decoupled isotropic and anisotropic polarizabilities.
- A shift in maximum parallel polarizability toward products signifies a more asynchronous mechanism.
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