Barriers to internal rotation in structural isomers of methylimidazole determined by broadband rotational spectroscopy

Gougoula, Eva

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https://hdl.handle.net/2142/104524 Copy

Description

Title

Barriers to internal rotation in structural isomers of methylimidazole determined by broadband rotational spectroscopy

Author(s)

Gougoula, Eva

Contributor(s)

• Walker, Nick
• Heitkämper, Juliane
• Medcraft, Chris

Issue Date

2019-06-17

Keyword(s)

• Large amplitude motions
• Internal rotation

Abstract

Imidazoles are a class of aromatic compounds with significant biochemical properties. Some imidazoles are found to be key compounds in cancer growth while functionalizing imidazole in order to synthesize new drugs is a field of increasing interest among medicinal chemists. The ground state rotational spectra of 1-, 2-, 4- and 5-methylimidazole were recorded in the 7.0-18.5 GHz frequency range by Chirped Pulse Fourier Transform Microwave Spectroscopy. Solid samples of 2-, 4-, and 5-methylimidazole were transferred into the gas phase through laser ablation in the presence of argon gas undergoing supersonic expansion. Liquid 1-methylimidazole was placed in a bespoke reservoir which allows direct introduction of the molecule into the flow of argon. Ground state rotational constants, A$_{0}$, B$_{0}$, C$_{0}$, centrifugal distortion constants, D$_{J}$, D$_{JK}$, D$_{K}$, d$_{1}$, d$_{2}$, and nuclear quadrupole coupling constants, x$_{aa}$(N), x$_{bb}$(N)-x$_{cc}$(N), were determined for all structural isomers of methylimidazole. Detection of 13C and 15N isotopologues in their natural abundance allowed for determination of atomic coordinates of heavy atoms. V$_{3}$ barriers to internal rotation of the methyl group were determined and provide an insight into the flexibility of the structural isomers.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/104524

DOI

https://doi.org/10.15278/isms.2019.MI01

Copyright and License Information

Copyright 2019 Eva Gougoula

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