Open AccessThe zwitterion of 4‐nitro‐2‐{( E )‐[2‐(piperidin‐1‐yl)ethyl]iminomethyl}phenol
Author(s) -
SantosContreras Rocio J.,
RamosOrganillo Angel,
GarcíaBáez Efrén V.,
PadillaMartínez Itzia I.,
MartínezMartínez Francisco J.
Publication year - 2009
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
eISSN - 1600-5759
pISSN - 0108-2701
DOI - 10.1107/s0108270108040407
Subject(s) - zwitterion , iminium , chemistry , schiff base , hydrogen bond , imine , nitro , intramolecular force , stereochemistry , medicinal chemistry , crystallography , molecule , organic chemistry , ion , alkyl , catalysis
The title Schiff base compound, 4‐nitro‐1‐oxo‐2‐{( E )‐[2‐(piperidin‐1‐yl)ethyl]iminiomethyl}cyclohexadienide, C 14 H 19 N 3 O 3 , exists as a zwitterion, with the H atom of the phenol group being transferred to the imine N atom. The C=O, C Ar —C Ar and C—N bond lengths are in agreement with the oxocyclohexadienide–iminium zwitterionic form. The iminium H atom is engaged in a strong intramolecular hydrogen bond with the O atom of the keto group (N + —H...O) to form an S (6) motif. Soft C—H...O interactions in the ac plane lead to the development of hydrogen‐bonded tapes, which are π‐stacked through the oxocyclohexadienide ring and iminium group. The significance of this study is in providing crystallographic evidence, supported by NMR and IR data, of the predominance of the oxocyclohexadienide–iminium zwitterion form over the noncharged canonical form in the title Schiff base.