Premium
Comparative analysis of hydrogen bonding with participation of the nitrogen, oxygen and sulfur atoms in the 2(2′‐heteroaryl)pyrroles and their trifluoroacetyl derivatives based on the 1 H, 13 C, 15 N spectroscopy and DFT calculations
Author(s) -
Afonin Andrei V.,
Vashchenko Alexander V.,
Ushakov Igor A.,
Zoridezhda V.,
Schmidt Elena Yu.
Publication year - 2008
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2197
Subject(s) - chemistry , sulfur , nitrogen , oxygen , hydrogen , hydrogen bond , oxygen atom , medicinal chemistry , organic chemistry , computational chemistry , molecule
The NHċbondX (X = N,O,S) intramolecular hydrogen bond in the series of 2(2′‐heteroaryl)pyrroles and their trifluoroacetyl derivatives is examined by the 1 H, 13 C, 15 N spectroscopy and density functional theory (DFT) calculations. The influence of the hydrogen bond on coupling and shielding constants is considered. It is shown that the NHċbondN intramolecular hydrogen bond causes a larger increase in the absolute size of the 1 J (N,H) coupling constant and a larger deshielding of the bridge proton than the NHċbondO hydrogen bond. The effect of the NHċbondS interaction on the 1 J (N,H) coupling constant and the shielding of the bridge proton is small. The NMR parameter changes in the series of the 2(2′‐heteroaryl)pyrroles due to NHċbondX hydrogen bond and the series of the 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles due to CHċbondX hydrogen bond have the same order. The proximity of the nitrogen, oxygen or sulfur lone pair to the FċbondH hydrogen bridge quenches the trans ‐hydrogen bond spin–spin couplings 1h J (F,H‐1) and 2h J (F,N). Copyright © 2008 John Wiley & Sons, Ltd.