C-H•••X (X = N, O, S) intramolecular interaction in 1-vinyl-2-(2′-heteroaryl)pyrroles as monitored by 1H and 13C NMR spectroscopy

H-1 and C-13 NMR spectroscopy of a series of 1-vinyl-2-(2'-heteroaryl)-pyrroles were employed for the analysis of their electronic and spatial structure. The C-(HN)-N-... intramolecular interaction between the a-hydrogen of the vinyl group and the pyridine nitrogen, a kind of hydrogen bonding, was detected in 1-vinyl-2-(2'-pyridyl)pyrrole, which disappeared in its iodide methyl derivative. It was shown that this interaction is stronger than the C-(HO)-O-... and C-(HS)-S-... interactions in 1-vinyl-2-(2'-furyl)- and -2-(2'-thienyl)-pyrroles. Copyright (C) 2001 John Wiley Sons, Ltd.