organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
mirror-symmetry conformation. On the other hand, the plane
of the C11–C16 phenyl group makes a dihedral angle of
21.9 (2)ꢁ with that of the pyrazole ring. There is a short
intramolecular C—Hꢀ ꢀ ꢀN contact involving atom C12
(Table 2), but the dihedral angle makes it possible that this is
actually a repulsive rather than an attractive contact. Apart
from the tert-butyl and phenyl substituents, the rest of the
molecular skeleton is nearly planar, as indicated by the leading
torsion angles (Table 1).
ISSN 0108-2701
3-[(E)-(3-tert-Butyl-1-phenyl-1H-
pyrazol-5-yl)iminomethyl]quinolin-
2(1H)-one: chains built by p-stacking
of hydrogen-bonded R22(8) dimers
a
a
´
Juan C. Castillo, Rodrigo Abonıa, Michael B.
Hursthouse,b Justo Coboc and Christopher Glidewelld*
a
´
´
´
Grupo de Investigacion de Compuestos Heterocıclicos, Departamento de Quımica,
Universidad de Valle, AA 25360 Cali, Colombia, bSchool of Chemistry, University of
Southampton, Highfield, Southampton SO17 1BJ, England, cDepartamento de
´
´
´
´
´
Quımica Inorganica y Organica, Universidad de Jaen, 23071 Jaen, Spain, and
dSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
Received 21 August 2009
Accepted 24 August 2009
Online 5 September 2009
In the title compound, C23H22N4O, there is evidence for some
bond fixation in the aryl component of the quinolinone unit.
Pairs of molecules related by inversion are linked into R22(8)
dimers by almost linear N—Hꢀ ꢀ ꢀO hydrogen bonds, and
dimers related by inversion are linked into chains by a single
aromatic ꢀ–ꢀ stacking interaction.
The supramolecular aggregation of (I) is dominated by a
fairly short and almost linear N—Hꢀ ꢀ ꢀO hydrogen bond
(Table 2). Pairs of these hydrogen bonds link molecules
related by inversion into R22(8) (Bernstein et al., 1995) dimers,
with the reference dimer centred at (0, 12, 21). A single aromatic
ꢀ–ꢀ stacking interaction links the hydrogen-bonded dimers
into a chain. The C11–C16 phenyl rings in the molecules at
(x, y, z) and (2 ꢂ x, 1 ꢂ y, 2 ꢂ z) are strictly parallel, with an
Comment
We report here the structure of the title compound, (I) (Fig. 1).
It is related to a series of 5-benzylamino-3-tert-butyl-1-phenyl-
1H-pyrazoles, the structures of which were reported recently
(Castillo et al., 2009), but differs from the earlier series in the
nature of its arylidene moiety, the bicyclic heterocyclic 2-oxo-
1,2-dihydro-3-quinolyl fragment, where the N—H and C
O
groups play the leading role in the supramolecular aggrega-
tion.
Although the C—C distances in the pendent aryl ring (C11–
˚
C16) span only a small range [1.380 (2)–1.392 (2) A], the C—C
distances in the aryl component of the quinolinone unit show
much wider variation (Table 1). In particular, the C65—C66
and C67—C68 distances (cf. Fig. 1) are significantly shorter
than the other distances in this ring, suggesting some bond
fixation analogous to that found in naphthalenes, so that the
resonance forms (I) and (Ia) (see scheme) are probably both
significant contributors to the overall electronic structure.
The tert-butyl substituent of (I) is oriented relative to the
pyrazole ring such that one of the methyl C atoms, C32, is
close to but displaced from the plane of the pyrazole ring, so
that the tert-butylpyrazole fragment has only approximate
local mirror symmetry. In effect (Table 1), the tert-butyl group
is rotated by ca 6ꢁ about the C3—C31 bond away from the
Figure 1
The molecular structure of (I), showing the atom-labelling scheme.
Displacement ellipsoids are drawn at the 30% probability level and H
atoms are shown as small spheres of arbitrary radii.
Acta Cryst. (2009). C65, o495–o497
doi:10.1107/S0108270109033861
# 2009 International Union of Crystallography o495
Castillo, Juan C.
