Hydrogen-bonded assembly in six closely related pyrazolo-[3,4-b]pyridine derivatives; A simple chain, three types of chains of rings and a complex sheet structure

Article abstract of DOI:10.1107/S0108270111050207

Six closely related pyrazolo-[3,4-b]pyridine derivatives, namely 6-chloro-3-methyl-1,4-diphenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C20H14ClN3O, (I), 6-chloro-3-methyl-4-(4-methyl-phenyl)-1-phenylpyrazolo-[3,4-b] pyridine-5-carbaldehyde, C21H16ClN3O, (II), 6-chloro-4-(4-chloro-phenyl)-3- methyl-1-phenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C20H13Cl2N3O, (III), 4-(4-bromo-phenyl)-6-chloro-3-methyl-1-phenyl-pyrazolo-[3,4-b] pyridine-5-carbaldehyde, C20H13BrClN3O, (IV), 6-chloro-4-(4-meth-oxy-phenyl)-3- methyl-1-phenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C21H16ClN3O2, (V), and 6-chloro-3-methyl-4-(4-nitro-phenyl)-1-phenyl-pyrazolo[3,4-b] pyridine-5-carbaldehyde, C20H13ClN4O3, (VI), which differ only in the identity of a single small substituent on one of the aryl rings, crystallize in four different space groups spanning three crystal systems. The mol-ecules of (I) are linked into a chain of rings by a combination of C - H...N and C - H...π(arene) hydrogen bonds; those of (II), (IV) and (V), which all crystallize in the space group P , are each linked by two independent C - H...O hydrogen bonds to form chains of edge-fused rings running in different directions through the three unit cells; the mol-ecules of (III) are linked into complex sheets by a combination of two C - H...O hydrogen bonds and one C - H...π(arene) hydrogen bond; finally, the mol-ecules of (VI) are linked by a single C - H...O hydrogen bond to form a simple chain.

Full text of DOI:10.1107/S0108270111050207

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
pounds are intended for use as precursors in the synthesis of
new fused heterocyclic systems with potential bioactivity. We
report here the molecular and supramolecular structures of six
closely-related 4-aryl-6-chloro-3-methyl-1-phenyl-pyrazolo-
[3,4-b]pyridine-5-carbaldehydes, (I)–(VI) (Figs. 1–6).
ISSN 0108-2701
Hydrogen-bonded assembly in six
closely related pyrazolo[3,4-b]-
pyridine derivatives; a simple chain,
three types of chains of rings and a
complex sheet structure
a
a
b
´
Jairo Quiroga, Yurina Dıaz, Justo Cobo and
Christopher Glidewellc*
a
´
Departamento de Quımica, Universidad de Valle, AA 25360 Cali, Colombia,
b
´
´
´
´
Departamento de Quımica Inorganica y Organica, Universidad de Jaen, 23071
Jaen, Spain, and cSchool of Chemistry, University of St Andrews, Fife KY16 9ST,
´
Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
Received 4 November 2011
Accepted 22 November 2011
Online 6 December 2011
Six closely related pyrazolo[3,4-b]pyridine derivatives, namely
6-chloro-3-methyl-1,4-diphenylpyrazolo[3,4-b]pyridine-5-
carbaldehyde, C20H14ClN3O, (I), 6-chloro-3-methyl-4-(4-
methylphenyl)-1-phenylpyrazolo[3,4-b]pyridine-5-carbalde-
hyde, C21H16ClN3O, (II), 6-chloro-4-(4-chlorophenyl)-3-
methyl-1-phenylpyrazolo[3,4-b]pyridine-5-carbaldehyde,
C20H13Cl2N3O, (III), 4-(4-bromophenyl)-6-chloro-3-methyl-
1-phenylpyrazolo[3,4-b]pyridine-5-carbaldehyde, C20H13BrCl-
N3O, (IV), 6-chloro-4-(4-methoxyphenyl)-3-methyl-1-phenyl-
pyrazolo[3,4-b]pyridine-5-carbaldehyde, C21H16ClN3O2, (V),
and 6-chloro-3-methyl-4-(4-nitrophenyl)-1-phenylpyrazolo-
[3,4-b]pyridine-5-carbaldehyde, C20H13ClN4O3, (VI), which
differ only in the identity of a single small substituent on one
of the aryl rings, crystallize in four different space groups
spanning three crystal systems. The molecules of (I) are linked
into a chain of rings by a combination of C—HÁ Á ÁN and C—
HÁ Á Áꢀ(arene) hydrogen bonds; those of (II), (IV) and (V),
which all crystallize in the space group P1, are each linked by
two independent C—HÁ Á ÁO hydrogen bonds to form chains of
edge-fused rings running in different directions through the
three unit cells; the molecules of (III) are linked into complex
sheets by a combination of two C—HÁ Á ÁO hydrogen bonds
and one C—HÁ Á Áꢀ(arene) hydrogen bond; finally, the mol-
ecules of (VI) are linked by a single C—HÁ Á ÁO hydrogen bond
to form a simple chain.
Despite differing by only the single substituent R at atom
C44 (see Scheme and Figs. 1–6), compounds (I)–(VI) show
some interesting variations in their crystallization character-
istics. Compound (III), where R = Cl, might well be expected
to be isomorphous either with (II), where R = Me, or with
(IV), where R = Br. In the event, (III) crystallizes in the
orthorhombic space group Pbcn, while (II) and (IV) both
crystallize in the triclinic space group P1, as does (V), where
R = OMe, while the nitro derivative (VI) crystallizes in the
monoclinic space group P21/c. Thus, these six rather similar
compounds crystallize in no fewer than four different space
groups (P1, P21/c, C2/c and Pbcn) spanning three crystal
systems. Despite their common space group, the unit-cell
dimensions of (II) and (IV) differ in that (II) has all the unit-
cell angles less than 90ꢀ and quite similar in value, while (IV)
has all the unit-cell angles greater than 90ꢀ and spanning a
range of ca 17ꢀ. Despite their different space groups, the
effective molecular volumes for (II), R = Me, and (III), R = Cl,
as calculated from Vcell/Z (see Crystal data), are identical
within experimental uncertainty, while the molecular volume
of (IV) (R = Br) is greater by only ca 2.4%.
Comment
We have recently described the preparation of a series of
6-chloropyrazolo[3,4-b]pyridine-5-carbaldehydes via tandem
chlorination–formylation of pyrazolopyridinones under Vils-
meier–Haack conditions (Quiroga et al., 2010). These com-
o12 # 2012 International Union of Crystallography
doi:10.1107/S0108270111050207
Acta Cryst. (2012). C68, o12–o18

organic compounds
Figure 1
The molecular structure of (I) (R = H), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
Figure 3
The molecular structure of (III) (R = Cl), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
None of the molecules of (I)–(VI) exhibit any internal
symmetry and all of them are conformationally chiral.
However, the centrosymmetric space groups all accommodate
equal numbers of the two conformational enantiomers. The
reference molecules of (I)–(VI) were selected to have the
same sign for the torsion angles N2—N1—C11—C12 defining
the orientation of the C11–C16 ring relative to the fused ring
system (Table 1 and Figs. 1–6), where the individual values
span a range of ca 40ꢀ. Similarly, the torsion angles C3A—
C4—C41—C42, defining the orientation of the C41–C46 ring
relative to the fused ring system, vary quite widely, spanning a
range of ca 60ꢀ. While it is perhaps tempting to associate the
variable orientation of the substituted C41–C46 aryl ring with
the fact that donors forming part of this ring participate in
hydrogen bonding in each of (I)–(VI), such an interpretation
could not be convincingly applied to the orientation of the
unsubstituted C11–C16 aryl ring, since the location of the
Figure 2
The molecular structure of (II) (R = Me), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
Figure 4
The molecular structure of (IV) (R = Br), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
ꢁ
Acta Cryst. (2012). C68, o12–o18
Quiroga et al.
C20H14ClN3O and five analogues o13

organic compounds
chloro-5-formylpyrimidines (Cobo et al., 2008). A number of
factors, including intra- and intermolecular hydrogen bonds
and electrostatic factors, were considered as possibly under-
lying the occurrence of the two different formyl conforma-
tions, but no single factor was regarded in that work as
providing a fully satisfactory interpretation of the observed
behaviour. Likewise for (I)–(VI) here, no clear and simple
interpretation of the formyl orientation presents itself.
The supramolecular assembly in (I)–(VI) is dominated by
C—HÁ Á ÁO hydrogen bonds (Table 2), but there is a C—HÁ Á ÁN
hydrogen bond in (I) and there are C—HÁ Á Áꢀ(arene)
hydrogen bonds in (I) and (III), where both compounds utilize
the C11–C16 aryl ring as the acceptor. Intermolecular contacts
of C—HÁ Á ÁO type have been regarded as structurally insig-
˚
nificant if: (a) the HÁ Á ÁO distance exceeds 2.60 A (cf. Bondi,
1964; Rowland & Taylor, 1996), (b) the C—HÁ Á ÁO angle is less
than 130ꢀ (cf. Wood et al., 2009) or (c) if the C—H bond
concerned forms part of a methyl group. Such C—H bonds are
of low acidity, and methyl groups H3C—E are likely to be
undergoing very rapid rotation about the C—E bonds
(Riddell & Rogerson, 1996, 1997), particularly when bonded
to aryl rings, where the sixfold rotational barriers are typically
only a few J molÀ1 (Tannenbaum et al., 1956; Naylor & Wilson,
1957). For compounds crystallizing in different space groups,
very different patterns of supramolecular assembly are
observed, but the three compounds which crystallize in the
space group P1, (II), (IV) and (V), all have rather similar
hydrogen-bonded structures, albeit with differences in detail.
In the structure of (I), in the space group C2/c, a combi-
nation of one C—HÁ Á ÁN and one C—HÁ Á Áꢀ(arene) hydrogen
bond links molecules related by the 21 screw axis along (34, y, 41)
Figure 5
The molecular structure of (V) (R = OMe), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
donor unit C14—H14, active in (II), (IV) and (V), is unaf-
fected by the value of the N2—N1—C11—C12 torsion angle.
Perhaps the most striking feature of the molecular confor-
mations in (I)–(VI) concerns the orientation of the formyl
group (Table 1 and Figs. 1–6), where the formyl O atom is
directed towards atom Cl61 in (II) and (V) but away from it in
all the other compounds. This type of behaviour has been
noted previously in a series of N6-substituted 2-amino-4-
Figure 7
Part of the crystal structure of (I), showing the formation of a chain of
rings along [010]. For the sake of clarity, H atoms not involved in the
motif shown have been omitted. Atoms marked with an asterisk (*), hash
(#), dollar sign ($) or ampersand (&) are at the symmetry positions (Àx + 32,
Figure 6
The molecular structure of (VI) (R = NO2), showing the atom-labelling
scheme. Displacement ellipsoids are drawn at the 30% probability level.
1
2
1
2
3
2
1
2
1
2
y À , Àz + ), (x, y À 1, z), (Àx + , y + , Àz + ) and (x, y + 1, z),
respectively.
ꢁ
o14 Quiroga et al.
C20H14ClN3O and five analogues
Acta Cryst. (2012). C68, o12–o18

organic compounds
related by translation into C(12) chains running parallel to the
[101], [110] and [110] directions in (II), (IV) and (V),
respectively. The combination of the two C—HÁ Á ÁO hydrogen
bonds leads in each case to the formation of a chain of edge-
fused rings. In (II), this chain of rings contains R22(14) rings
1
centred at (12 + n, , 1 À n), where n represents an integer,
2
alternating with R24(26) rings centred at (n, 21, 23 À n) (Fig. 8); in
(IV), R22(16) rings centred at (n, n, 0) alternate with R24(28)
1
2
1
2
rings centred at (12 + n, + n, ) (Fig. 11); and in (V), R22(14)
rings centred at (12 + n, Àn, 0) alternate with R24(26) rings
1
2
1
2
centred at (n, À n, ) (Fig. 12), where in every case n
represents an integer.
The hydrogen-bonded assembly in (III) is two-dimensional
and of considerably greater complexity than the other hydro-
gen-bonded structures reported here. However, it can be
straightforwardly analysed in terms of a one-dimensional
substructure. Atom C15 in the molecule at (x, y, z) acts as
hydrogen-bond donor to atom O51 in the molecule at (Àx + 1,
y À 1, Àz + 32), while atom C15 at (Àx + 1, y À 1, Àz + 32) in turn
acts as donor to atom O51 at (x, y À 2, z), so forming a C(11)
chain running parallel to the [010] direction. There are, in fact,
two such chains around the 21 screw axis along (12, y, 43), related
to one another by a unit translation along [010], and these two
chains are linked to one another by a C—HÁ Á Áꢀ(arene)(Àx + 1,
y, Àz + 32) hydrogen bond to form a one-dimensional
substructure (Fig. 9).
Figure 8
A stereoview of part of the crystal structure of (II), showing the
formation of a chain of edge-fused R22(14) and R42(26) rings along [101].
For the sake of clarity, H atoms not involved in the motif shown have
been omitted.
to form a chain of rings running parallel to the [010] direction
(Fig. 7). Four chains of this type, each containing molecules
related to one another by one of the four screw axes along
(14, y, 14), (14, y, 34), (43, y, 14) and (43, y, 34), pass through each unit cell,
but there are no direction-specific interactions between adja-
cent chains.
There are two C—HÁ Á ÁO hydrogen bonds in the structures
of each of (II), (IV) and (V) (Table 2). One of these hydrogen
bonds, where the donor forms part of the C41–C46 ring, links
pairs of molecules related by inversion, forming centrosym-
metric R22(14) (Bernstein et al., 1995) rings in each of (II) and
(V) (Figs. 8 and 12) and a centrosymmetric R22(16) ring in (IV)
(Fig. 11). The second hydrogen bond, which utilizes the same
donor atom in each of the three compounds, links molecules
The action of the second C—HÁ Á ÁO hydrogen bond in (III)
is to link the double chains which run parallel to [010] into a
sheet. Atoms C43 in the molecules at (x, y, z) and (Àx + 1,
3
y À 1, Àz + ), which are both components of a chain along
2
1
2
(12, y, ), act as hydrogen-bond donors to atoms O51 in the
3
1
1
3
3
molecules at (Àx + , y À , z) and (x À , y À , Àz + ),
2
2
2
2
2
respectively, which themselves form parts of C(11) chains
3
3
4
along (1, y, ) and (0, y, ), respectively, so leading to the
4
formation of a sheet lying parallel to (001) (Fig. 10). This sheet
lies in the domain 12 < z < 1.0, and a second sheet, related to the
first by inversion, lies in the domain 0 < z < 12, but there are no
direction-specific interactions between adjacent sheets. Thus,
compound (III), despite having a constitution and steric
Figure 9
A stereoview of part of the crystal structure of (III), showing the
Figure 10
3
formation of two translation-related C(11) chains around (12, y, ), built
A stereoview of part of the crystal structure of (III), showing the linking
of the chains along [010] to form a sheet lying parallel to (001). For the
sake of clarity, H atoms not involved in the motif shown have been
omitted.
4
from C—HÁ Á ÁO hydrogen bonds and linked by a C—HÁ Á Áꢀ(arene)
hydrogen bond. For the sake of clarity, H atoms not involved in the motif
shown have been omitted.
ꢁ
Acta Cryst. (2012). C68, o12–o18
Quiroga et al.
C20H14ClN3O and five analogues o15

organic compounds
potential hydrogen-bond acceptors within each molecule, in
fact has the simplest hydrogen-bonded structure in this series.
The wide range of space groups observed here, together
with the different modes of hydrogen-bonded assembly,
certainly suggest that series of this type might provide an
interesting challenge for structure-prediction algorithms (Day
et al., 2005, 2009).
Experimental
A suspension of the appropriate 4-aryl-3-methyl-1-phenyl-4,5-di-
hydro-1H-pyrazolo[3,4-b]pyridin-6(7H)-one (1 mmol) in dimethyl-
formamide (2 ml) was cooled using an ice–water bath, and then
phosphoryl chloride (0.2 ml, 2.1 mmol) was added dropwise. Each
reaction mixture was stirred for 30 min at ambient temperature and
subsequently heated at 373 K for 5 h. After cooling to ambient
temperature by the addition of ice, the reaction mixture was
neutralized using sodium hydrogen carbonate solution with vigorous
stirring. In each case, the resulting yellow precipitate was collected by
filtration, dried and recrystallized from dimethylformamide to afford
yellow crystals suitable for single-crystal X-ray diffraction.
Figure 11
A stereoview of part of the crystal structure of (IV), showing the
formation of a chain of edge-fused R22(16) and R42(28) rings along [110].
For the sake of clarity, H atoms not involved in the motif shown have
been omitted.
Compound (I)
Crystal data
3
˚
C20H14ClN3O
Mr = 347.79
V = 3322.5 (9) A
Z = 8
Monoclinic, C2=c
Mo Kꢂ radiation
ꢃ = 0.24 mmÀ1
T = 120 K
0.36 Â 0.32 Â 0.12 mm
˚
a = 16.784 (3) A
˚
b = 9.6380 (8) A
˚
c = 21.699 (4) A
ꢁ = 108.820 (12)ꢀ
Data collection
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.918, Tmax = 0.972
24328 measured reflections
3829 independent reflections
2899 reflections with I > 2ꢄ(I)
Rint = 0.042
Refinement
R[F2 > 2ꢄ(F2)] = 0.040
wR(F2) = 0.100
S = 1.05
227 parameters
H-atom parameteÀrs3 constrained
˚
Áꢅmax = 0.49 e A
À3
˚
3829 reflections
Áꢅmin = À0.37 e A
Figure 12
A stereoview of part of the crystal structure of (V), showing the
formation of a chain of edge-fused R22(14) and R42(26) rings along [110].
For the sake of clarity, H atoms not involved in the motif shown have
been omitted.
Compound (II)
Crystal data
C21H16ClN3O
Mr = 361.82
Triclinic, P1
a = 8.2898 (8) A
b = 9.9191 (14) A
˚
c = 10.3666 (10) A
ꢂ = 87.108 (11)ꢀ
ꢁ = 86.808 (8)ꢀ
ꢆ = 85.088 (12)ꢀ
V = 847.08 (17) A
Z = 2
Mo Kꢂ radiation
ꢃ = 0.24 mmÀ1
T = 120 K
3
˚
properties, as manifested by the molecular volume, very
similar to those of (II) and (IV), not only crystallizes in a
different crystal system but also adopts a very different, and
much more complex, pattern of supramolecular assembly.
In the structure of (VI), in the space group P21/c, a single
C—HÁ Á ÁO hydrogen bond links molecules related by the 21
˚
˚
0.31 Â 0.26 Â 0.20 mm
1
4
Data collection
screw axis along (0, y, ) into a simple C(8) chain. Two such
chains, related to one another by inversion, pass through each
unit cell, but there are no direction-specific interactions
between adjacent chains. It is interesting to note that (VI),
where R = NO2 and thus having the largest number of
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.929, Tmax = 0.953
21387 measured reflections
3880 independent reflections
2544 reflections with I > 2ꢄ(I)
Rint = 0.074
ꢁ
o16 Quiroga et al.
C20H14ClN3O and five analogues
Acta Cryst. (2012). C68, o12–o18

organic compounds
Refinement
Data collection
R[F2 > 2ꢄ(F2)] = 0.050
wR(F2) = 0.130
S = 1.03
237 parameters
H-atom parameteÀrs3 constrained
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.935, Tmax = 0.968
21671 measured reflections
3975 independent reflections
3265 reflections with I > 2ꢄ(I)
Rint = 0.038
˚
Áꢅmax = 0.31 e A
À3
˚
3880 reflections
Áꢅmin = À0.30 e A
Refinement
Compound (III)
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.090
S = 1.06
246 parameters
H-atom parameteÀrs3 constrained
Crystal data
˚
Áꢅmax = 0.30 e A
Áꢅmin = À0.34 e A
3
˚
V = 3391 (2) A
Z = 8
À3
C20H13Cl2N3O
Mr = 382.23
Orthorhombic, Pbcn
˚
3975 reflections
Mo Kꢂ radiation
ꢃ = 0.40 mmÀ1
T = 120 K
0.40 Â 0.37 Â 0.28 mm
˚
a = 20.868 (3) A
˚
b = 9.603 (4) A
Compound (VI)
˚
c = 16.924 (9) A
Crystal data
Data collection
3
˚
V = 1776 (2) A
Z = 4
C20H13ClN4O3
Mr = 392.79
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.857, Tmax = 0.897
34307 measured reflections
3898 independent reflections
2444 reflections with I > 2ꢄ(I)
Rint = 0.080
Monoclinic, P21=c
Mo Kꢂ radiation
ꢃ = 0.25 mmÀ1
T = 120 K
0.39 Â 0.29 Â 0.14 mm
˚
a = 11.7839 (13) A
˚
b = 9.9890 (4) A
˚
c = 15.71 (2) A
ꢁ = 106.084 (8)ꢀ
Refinement
R[F2 > 2ꢄ(F2)] = 0.053
wR(F2) = 0.147
S = 1.08
236 parameters
H-atom parameteÀrs3 constrained
Table 1
Selected torsion angles (ꢀ) for (I)–(VI).
˚
Áꢅmax = 0.62 e A
À3
˚
3898 reflections
Áꢅmin = À0.46 e A
Compound N2—N1—C11—C12 C3A—C4—C41—C42 C4—C5—C51—O51
(I)
À140.93 (16)
À173.2 (2)
À73.6 (2)
À53.6 (3)
À56.7 (4)
À115.5 (3)
À55.9 (2)
À88.6 (2)
À10.2 (3)
147.5 (2)
À24.9 (5)
13.8 (4)
150.72 (16)
1.8 (3)
(II)
(III)
(IV)
(V)
(VI)
Compound (IV)
À135.7 (3)
À155.9 (2)
Crystal data
À177.26 (14)
À167.68 (18)
C20H13BrClN3O
Mr = 426.68
Triclinic, P1
a = 9.3826 (11) A
b = 9.7781 (12) A
ꢆ = 90.911 (10)ꢀ
V = 867.61 (16) A
Z = 2
Mo Kꢂ radiation
ꢃ = 2.54 mmÀ1
T = 120 K
3
˚
˚
˚
˚
Table 2
Geometry of hydrogen bonds and short intramolecular contacts (A, ) for
(I)–(VI).
ꢀ
˚
c = 10.1072 (6) A
ꢂ = 108.077 (10)ꢀ
ꢁ = 99.353 (9)ꢀ
0.36 Â 0.27 Â 0.20 mm
Cg1 represents the centroid of the C11–C16 ring.
Data collection
D—HÁ Á ÁA
D—H
HÁ Á ÁA
DÁ Á ÁA
D—HÁ Á ÁA
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.440, Tmax = 0.604
23897 measured reflections
3981 independent reflections
3098 reflections with I > 2ꢄ(I)
Rint = 0.048
(I)
C46—H46Á Á ÁN2i
0.95
0.95
2.58
2.76
3.515 (2)
3.508 (2)
169
136
C45—H45Á Á ÁCg1i
(II)
C14—H14Á Á ÁO51ii
0.95
0.95
2.46
2.41
3.319 (3)
3.348 (3)
150
170
Refinement
C46—H46Á Á ÁO51iii
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.077
S = 1.05
236 parameters
H-atom parameteÀrs3 constrained
(III)
C15—H15Á Á ÁO51iv
C43—H43Á Á ÁO51v
C42—H42Á Á ÁCg1vi
0.95
0.95
0.95
2.56
2.50
2.75
3.433 (4)
3.381 (4)
3.653 (4)
153
154
160
˚
Áꢅmax = 0.63 e A
À3
˚
3981 reflections
Áꢅmin = À0.42 e A
(IV)
C14—H14Á Á ÁO51vii
0.95
0.95
2.55
2.49
3.448 (4)
3.397 (3)
157
160
Compound (V)
C45—H45Á Á ÁO51viii
Crystal data
(V)
C14—H14Á Á ÁO51ix
C21H16ClN3O2
Mr = 377.82
Triclinic, P1
ꢆ = 86.665 (16)ꢀ
0.95
0.95
2.43
2.36
3.312 (2)
3.300 (2)
154
171
C46—H46Á Á ÁO51x
3
˚
V = 865.9 (3) A
Z = 2
˚
˚
(VI)
C45—H45Á Á ÁO51xi
a = 8.6972 (8) A
Mo Kꢂ radiation
ꢃ = 0.24 mmÀ1
T = 120 K
0.28 Â 0.19 Â 0.14 mm
0.95
2.41
3.261 (2)
150
b = 10.039 (2) A
˚
c = 10.090 (2) A
Symmetry codes: (i) Àx + 32, y À , Àz + 21; (ii) x + 1, y, z À 1; (iii) Àx + 1, Ày + 1, Àz + 2;
1
2
ꢂ = 85.23 (2)ꢀ
(iv) Àx + 1, y À 1, Àz + 32; (v) Àx + 23, y À , z; (vi) Àx + 1, y, Àz + 32; (vii) x + 1, y + 1, z; (viii)
1
2
ꢁ = 80.856 (16)ꢀ
Àx, Ày, Àz; (ix) x À 1, y + 1, z; (x) Àx + 1, Ày, Àz + 1; (xi) Àx, y À 12, Àz + 21.
ꢁ
Acta Cryst. (2012). C68, o12–o18
Quiroga et al.
C20H14ClN3O and five analogues o17

organic compounds
Data collection
´ ´
Andalucıa, Spain) and the Universidad de Jaen for financial
support.
Bruker–Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.910, Tmax = 0.966
25554 measured reflections
4073 independent reflections
2914 reflections with I > 2ꢄ(I)
Rint = 0.049
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: YF3009). Services for accessing these data are
described at the back of the journal.
Refinement
R[F2 > 2ꢄ(F2)] = 0.048
wR(F2) = 0.134
S = 1.09
254 parameters
H-atom parameteÀrs3 constrained
References
˚
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Int. Ed. Engl. 34, 1555–1573.
Bondi, A. (1964). J. Phys. Chem. 68, 441–452.
Áꢅmax = 0.42 e A
À3
˚
4073 reflections
Áꢅmin = À0.34 e A
Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De
Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38,
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Glidewell, C. (2008). Acta Cryst. B64, 596–609.
All H atoms were located in difference maps and then treated as
riding atoms in geometrically idealized positions, with C—H = 0.95
˚
(aromatic and formyl H) or 0.98 A (methyl H), and with Uiso(H) =
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refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction:
EVALCCD (Duisenberg et al., 2003); program(s) used to solve
structure: SIR2004 (Burla et al., 2005); program(s) used to refine
structure: SHELXL97 (Sheldrick, 2008); molecular graphics:
PLATON (Spek, 2009); software used to prepare material for
publication: SHELXL97 and PLATON.
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´
´
Quiroga, J., Dıaz, Y., Insuasty, B., Abonıa, R., Nogueras, M. & Cobo, J. (2010).
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¨
Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Gottingen,
Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Spek, A. L. (2009). Acta Cryst. D65, 148–155.
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´
´
The authors thank the Centro de Instrumentacion Cientı-
´
´
fico-Tecnica of the Universidad de Jaen and the staff for the
data collections. JQ and YD thank COLCIENCIAS and the
Universidad del Valle for financial support. JC thanks the
´ ´
Consejerıa de Innovacion, Ciencia y Empresa (Junta de
ꢁ
o18 Quiroga et al.
C20H14ClN3O and five analogues
Acta Cryst. (2012). C68, o12–o18