Targeting the rich conformational landscape of N-allylmethylamine using rotational spectroscopy and quantum mechanical calculations
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Date
2020-10-03
Authors
Silva, Weslley G. D. P.
Poonia, Tamanna
van Wijngaarden, Jennifer
Journal Title
Journal ISSN
Volume Title
Publisher
ChemPhysChem
Abstract
The highly variable conformational landscape of N-allylmethylamine (AMA) was investigated using Fourier transform microwave spectroscopy aided by high-level theoretical calculations to understand the energy relationship governing the interconversion between nine stable conformers. Spectroscopically, transitions belonging to four low energy conformers were identified and their hyperfine patterns owing to the 14N quadrupolar nucleus were unambiguously resolved. The rotational spectrum of the global minimum geometry, conformer I, shows an additional splitting associated with a tunneling motion through an energy barrier interconnecting its enantiomeric forms. A two-step tunneling trajectory is proposed by finding transition state structures corresponding to the allyl torsion and NH inversion. Natural bond orbital and non-covalent interaction analyses reveal that an interplay between steric and hyperconjugative effects rules the conformational preferences of AMA.
Description
Keywords
microwave spectroscopy, quantum chemistry calculations, potential energy surface, conformational preferences
Citation
Silva, W. G. D. P.; Poonia, T.; van Wijngaarden, J. Targeting the rich conformational landscape of N-allylmethylamine using rotational spectroscopy and quantum mechanical calculations. ChemPhysChem 2020, 21, 2515