organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
6-Aminonicotinic acid hydrochloride
Figure 1
John Giantsidis and Mark M. Turnbull*
The molecular structure of (I) showing 50% probability displacement
ellipsoids and the atom-numbering scheme. H atoms are drawn as circles
of an arbitrary radius.
Carlson School of Chemistry and Biochemistry, Clark University, 950 Main St.,
Worcester, MA 01610, USA
Correspondence e-mail: mturnbull@clarku.edu
A view of the molecule is shown in Fig. 1. The aromatic ring
Ê
of (I) is planar, with a mean plane deviation of 0.0047 A. The
Received 22 July 1999
Accepted 17 November 1999
carboxyl and the amino groups are canted from that plane,
likely as a result of hydrogen bonding in the lattice as in 2-
aminonicotinic acid acid (Dobson & Gerkin, 1997).
The crystal lattice exists as nearly planar sheets of proto-
nated 6-aminonicotinic acid molecules and chloride ions that
run roughly parallel to the b face (see Fig. 2). The plane of the
ring is canted 3.8 (2)ꢁ relative the b face. The ring axis, de®ned
as the C2±C5 vector, is inclined at an angle of 16.4 (2)ꢁ relative
The title compound, 2-amino-5-carboxypyridinium chloride,
+
C6H7N2O2 ÁCl , was isolated from a 1 M HCl aqueous
solution containing 2-amino-5-cyanopyridine. The structure
is held together by extensive hydrogen bonding between the
chloride ions and the carboxylic acid, amino and pyridinium H
atoms. The molecules pack as sheets, with the sheets at a
Ê
distance of 3.21 (3) A from one another.
Ê
to the c axis. The layers are close together [3.21 (3) A], but are
not linked by hydrogen bonding. However, within the sheets,
hydrogen bonds form from the pyridinium proton to the
chloride ion, and from one of the amino protons to the choride
ion (Table 2). Also, there is a weak hydrogen bond from the
other amino proton to the carbonyl oxygen. Even though the
distance between N2 and O2 is the shortest, the angle is far
from linear, resulting in a weaker interaction. An additional
hydrogen bond forms from the carboxylic proton to the
chloride ion.
Crystals of the 5-cyano compound are being prepared under
anhydrous conditions and the use of 6-aminonicotinic acid for
the preparation of low-dimensional magnetic lattices is
underway.
Comment
In our laboratories we are interested in the preparation and
study of low-dimensional magnetic lattices which have the
general formula A2MX4, where M is a 2+ transition metal ion,
X = Cl or Br and A is a protonated organic base. Usually, these
compounds pack in crystal lattices that create interesting low-
dimensional magnetic lattices. The magnetic lattice arises from
interactions between the MX4 ions. The nature of these
interactions is controlled by the crystal lattice, which changes
as the organic base is changed. Aromatic compounds
containing substituents in the 5-position, such 2-amino-5-
methylpyridine (Place & Willett, 1987) and 2-amino-5-
chloropyridine (Albrecht, Landi et al., 1997; Albrecht, Wynn et
al., 1999; Hammar et al., 1997) have been shown to have very
interesting magnetic properties. 2-Amino-5-cyanopyridine
was synthesized according to the procedure of Gregory et al.
(1947) in order to compare its suitability as a base with that of
the previously mentioned derivatives. We have prepared metal
complexes of 2-amino-5-cyanopyridine (J. Giantsidis & M. M.
Turnbull, unpublished results) and were interested in what
kind of interactions we might expect between the organic
groups themselves. In the course of these studies, 6-amino-
nicotinic acid hydrochloride, (I), was crystallized from a
solution of 2-amino-5-cyanopyridine in aqueous HCl and its
structure is presented here.
Figure 2
Packing diagram for (I) showing the hydrogen bonding and the
relationship between successive sheets within the lattice.
ꢀ
334 # 2000 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2000). C56, 334±335
Giantsidis, John
