The Gas Phase Protonation Sites of Six Naturally Occurring Nicotinoids.
J Phys Chem Lett
; 15(27): 6966-6973, 2024 Jul 11.
Article
em En
| MEDLINE
| ID: mdl-38940770
ABSTRACT
The gas phase protonation sites of six naturally occurring nicotinoids, namely nicotine (NIC), nornicotine (NOR), anabasine (ANB), anatabine (ANT), cotinine (COT), and myosmine (MYO), consisting of a common Pyridine and differing non-Pyridine rings, have been determined for the first time at the physiological temperature from cryogenic ion trap infrared spectroscopy and electronic structure calculations. The protonation site on either of these two rings is related to the nicotinoid's biological activity. At room temperature, NIC is a mixture of Pyridine and Pyrrolidine (non-Pyridine) protomers, whereas NOR, ANB, ANT, and COT are pure Pyridine protomers and finally MYO is mostly a Pyroline (non-Pyridine) protomer. The nearly planar structure of MYO-H+, induced by the presence of a conjugated π system and confirmed from calculations and the UV absorption spectra, breaks from the trends observed for NIC, NOR, and ANB, since its structure is drastically different from the structures of the other nicotinoids.
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1
Base de dados:
MEDLINE
Assunto principal:
Prótons
/
Gases
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article