Assembling an isomer grid: The isomorphous 4-, 3- and 2-fluoro-N′-(4- pyrid-yl)benzamides

Article abstract of DOI:10.1107/S0108270108012067

The three title isomers, 4-, (I), 3-, (II), and 2-fluoro-N′-(4-pyri- d-yl)benzamide, (III), all C12H9FN2O, crystallize in the P21/c space group (No. 14) with similar unit-cell parameters and are isomorphous and isostructural at the primary hydrogen-bonding level. An intra-molecular C - H...O=C inter-action is present in all three isomers [C...O = 2.8681 (17)-2.884 (2) A and C - H...O117-118°], with an additional N - H...F [N...F = 2.7544 (15) A] inter-action in (III). Inter-molecular amide-pyridine N - H...N hydrogen bonds link mol-ecules into one-dimensional zigzag chains [graph set C(6)] along the [010] direction as the primary hydrogen bond [N...N = 3.022 (2), 3.049 (2) and 3.0213 (17) A]. These are augmented in (I) by C - H...π(arene) and cyclic C - F...π(arene) contacts about inversion centres, in (II) by C - F...F - C inter-actions [C...F = 3.037 (2) A] and weaker C - H...π(arene)/C - H...F contacts, and in (III) by C - H...π(arene) and C=O...O=C inter-actions, linking the alternating chains into two-dimensional sheets. Typical amide N - H...O=C hydrogen bonds [as C(4) chains] are not present [N...O = 3.438 (2) A in (I), 3.562 (2) A in (II) and 3.7854 (16) A in (III)]; the C=O group is effectively shielded and only participates in weaker inter-actions/contacts. This series is unusual as the three isomers are isomorphous (having similar unit-cell parameters, packing and alignment), but they differ in their inter-actions and contacts at the secondary level. International Union of Crystallography 2008.

Full text of DOI:10.1107/S0108270108012067

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
predicting crystal structures continues to greatly expand
knowledge from first principles, it is the drive amongst
synthetic chemists and chemical crystallographers to assemble
comprehensive sets of crystal structure data that will provide a
continual challenge to but also aid in the ongoing develop-
ment of this predictive science (Day et al., 2005). A relatively
facile method of obtaining extensive and related crystal
structure data sets is the assembly of isomer grids and
subsequent grid expansion (with polymorphs of individual
compounds), using variable solvent content and cocrystalli-
zations to generate pseudopolymorphs, and using variable-
temperature studies to analyse potential phase changes. We
report here the molecular and crystal structures of the 4-, 3-
and 2-fluoro-N0-(4-pyridyl)benzamide isomers, (I)–(III)
(Figs. 1–3), obtained from the reaction of 4-, 3- and 2-fluoro-
benzoyl chloride and 4-aminopyridine. This is the first in a
series of studies of isomers and model compounds for the
assembly of an isomer grid.
ISSN 0108-2701
Assembling an isomer grid: the
isomorphous 4-, 3- and 2-fluoro-
N0-(4-pyridyl)benzamides
Katie Donnelly,a John F. Gallaghera* and Alan J. Loughb
aSchool of Chemical Sciences, Dublin City University, Dublin 9, Ireland, and
bDepartment of Chemistry, 80 St George Street, University of Toronto, Ontario,
Canada M5S 3H6
Correspondence e-mail: john.gallagher@dcu.ie
Received 22 April 2008
Accepted 25 April 2008
Online 21 May 2008
The three title isomers, 4-, (I), 3-, (II), and 2-fluoro-N0-(4-
pyridyl)benzamide, (III), all C12H9FN2O, crystallize in the
P21/c space group (No. 14) with similar unit-cell parameters
and are isomorphous and isostructural at the primary
hydrogen-bonding level. An intramolecular C—Hꢀ ꢀ ꢀO
C
interaction is present in all three isomers [Cꢀ ꢀ ꢀO =
ꢁ
˚
2.8681 (17)–2.884 (2) A and C—Hꢀ ꢀ ꢀO117–118 ], with an
˚
additional N—Hꢀ ꢀ ꢀF [Nꢀ ꢀ ꢀF = 2.7544 (15) A] interaction in
(III). Intermolecular amide–pyridine N—Hꢀ ꢀ ꢀN hydrogen
bonds link molecules into one-dimensional zigzag chains
[graph set C(6)] along the [010] direction as the primary hydro-
˚
gen bond [Nꢀ ꢀ ꢀN = 3.022 (2), 3.049 (2) and 3.0213 (17) A].
These are augmented in (I) by C—Hꢀ ꢀ ꢀꢀ(arene) and cyclic
C—Fꢀ ꢀ ꢀꢀ(arene) contacts about inversion centres, in (II) by
˚
C—Fꢀ ꢀ ꢀF—C interactions [Cꢀ ꢀ ꢀF = 3.037 (2) A] and weaker
C—Hꢀ ꢀ ꢀꢀ(arene)/C—Hꢀ ꢀ ꢀF contacts, and in (III) by C—
Hꢀ ꢀ ꢀꢀ(arene) and C Oꢀ ꢀ ꢀO C interactions, linking the
alternating chains into two-dimensional sheets. Typical amide
N—Hꢀ ꢀ ꢀO C hydrogen bonds [as C(4) chains] are not
The geometric data (bond lengths and angles) in (I)–(III)
are normal and are not discussed except for some comparisons
and with reference to the hydrogen bonding. It is of note that
˚
the C—F bond lengths differ markedly [1.365 (2) A in (I),
˚
˚
present [Nꢀ ꢀ ꢀO = 3.438 (2) A in (I), 3.562 (2) A in (II) and
˚
˚
1.354 (2) A (II) and 1.3451 (16) A (III)], probably as a result
of the secondary hydrogen bonding (see below). The F atom is
located cisoid to the C O group in (II) but transoid in (III).
˚
3.7854 (16) A in (III)]; the C O group is effectively shielded
and only participates in weaker interactions/contacts. This
series is unusual as the three isomers are isomorphous (having
similar unit-cell parameters, packing and alignment), but they
differ in their interactions and contacts at the secondary
level.
Comment
Structural systematics of small molecules has undergone an
enormous change in the past decade with technical advances
in the ability to collect and analyse many crystal structures
within a short timeframe. Of interest in this research are
studies on polymorphism, pseudopolymorphism and isomers
and their impact on the development of new materials
(Gelbrich et al., 2007; Wardell et al., 2007, 2008). As progress in
Figure 1
A view of (I), showing the atomic numbering scheme. Displacement
ellipsoids are drawn at the 30% probability level.
Acta Cryst. (2008). C64, o335–o340
doi:10.1107/S0108270108012067
# 2008 International Union of Crystallography o335

organic compounds
No noticeable trends are evident from analysis of the bond-
angle data. The defining feature of the molecular conforma-
tion is the benzene–pyridine dihedral angle, which is mutually
oriented at 51.95 (6)ꢁ in (I), 48.75 (6)ꢁ in (II) and 46.34 (5)ꢁ
(III) (see the torsion angles in Tables 1, 3 and 5); pyramida-
lization is not discernible at the amide N1 atom, with angles
summing to within 3ꢁ of 360ꢁ.
For molecular comparisons, the asymmetric units have been
chosen to be close to the origin and with the molecular axes
aligned in similar orientations. A key feature in all three
isomers is the intramolecular interaction between atoms C26
and O1 [with an S(6) motif], with C26ꢀ ꢀ ꢀO1 in the narrow
˚
range of 2.87 ꢂ 0.01 A. In (III), there is an additional intra-
˚
molecular N—Hꢀ ꢀ ꢀF interaction [Nꢀ ꢀ ꢀF = 2.7544 (15) A]
between the ortho-F and amide NH atoms (see Tables 2, 4
and 6).
The defining and primary intermolecular interaction in all
three systems is the amide–pyridine N—Hꢀ ꢀ ꢀN hydrogen
bond that links molecules into one-dimensional zigzag chains
[graph set C(6)] along the [010] direction [with Nꢀ ꢀ ꢀN
˚
distances of 3.022 (2), 3.049 (2) and 3.0213 (17) A].
Figure 2
A view of (II), showing the atomic numbering scheme. Displacement
ellipsoids are drawn at the 30% probability level.
Figure 3
A view of (III), showing the atomic numbering scheme. Displacement
ellipsoids are drawn at the 30% probability level.
Figure 5
A view of the packing and C—Fꢀ ꢀ ꢀꢀ(arene) contacts in (I), with atoms
depicted as their van der Waals spheres. The hash symbol (#) denotes an
inversion-symmetry-related molecule at position (ꢄx + 2, ꢄy, ꢄz + 1).
The asterisk (*) indicates the pyridine ring defined in Fig. 4.
Figure 4
The primary N—Hꢀ ꢀ ꢀN interactions in (I); H atoms not involved in
hydrogen bonding have been omitted for clarity. The pyridine ring at
position (x, ꢄy + 12, z + 12) [labelled with an asterisk (*)] participates in an
Figure 6
The primary N—Hꢀ ꢀ ꢀN interactions in (II); H atoms not involved in these
1
2
1
2
Fꢀ ꢀ ꢀꢀ(arene) contact. [Symmetry codes: (i) ꢄx + 1, y + , ꢄz + ; (ii)
interactions have been omitted. [Symmetry codes: (i) ꢄx + 1, y + 12, ꢄz + 21;
1
1
1
2
1
2
ꢄx + 1, y ꢄ , ꢄz + .]
(ii) ꢄx + 1, y ꢄ , ꢄz + .]
2
2
ꢃ
o336 Donnelly et al. C12H9FN2O
Acta Cryst. (2008). C64, o335–o340

organic compounds
In (I), weaker C—Hꢀ ꢀ ꢀꢀ(arene) and C—Fꢀ ꢀ ꢀꢀ(arene)
closest intermolecular Nꢀ ꢀ ꢀO contact [N1ꢀ ꢀ ꢀO1(x ꢄ 1, y, z) =
ꢁ
˚
˚
contacts (about inversion centres) link alternating chains into
˚
3.7854 (16) A along [100]; N—Hꢀ ꢀ ꢀO = 135 ] is ꢅ0.75 A
longer and ca 4ꢁ smaller in angle than the amide–pyridine N—
Hꢀ ꢀ ꢀN interaction.
v
a two-dimensional sheet [Table 2; F14ꢀ ꢀ ꢀC21 = 3.091 (2) A;
symmetry code: (v) x, ꢄy + 12, z + 21], with each chain dove-
tailing into its two nearest neighbouring chains aligned in the
opposite direction along [010] (Figs. 4 and 5). There are no
C—Hꢀ ꢀ ꢀF—C or C—Fꢀ ꢀ ꢀF—C interactions.
All three isomers have similar unit-cell parameters in the
monoclinic space group P21/c (No. 14), and have similar
packing and hydrogen-bond motifs (similar at the primary
level but different at the secondary interaction levels), and
they are isomorphous (in the strict interpretation of the defi-
nition, as the atom-site coordinates coincide) in the solid state.
The close similarity in the packing of all three structures is
relatively easy to visualize (Figs. 4, 6 and 8 display three zigzag
chains with the unit-cell axes). For comparison, the unit-cell
similarity index, Å, is less than 0.015 for the (I)/(II)/(III) pairs
In (II), the primary interaction is augmented by three
weaker C—Hꢀ ꢀ ꢀꢀ(arene) contacts per molecule, linking the
alternating chains into a two-dimensional sheet (Table 4); each
chain dovetails as in (I) (Figs. 6 and 7). Instead of C—Fꢀ ꢀ ꢀ
ꢀ(arene) facial contacts as for (I), the location of the F atom
provides alternative interaction sites. The most notable is the
C13—F13ꢀ ꢀ ꢀ(F13–C13)vi contact about an inversion centre
vi
[F13ꢀ ꢀ ꢀC13vi = 3.037 (2) A and F13ꢀ ꢀ ꢀF13 = 3.1180 (17) A;
(Kalman et al., 1993); homeostructural crystal pairs and
packing ‘similarities’ generated by substituent migration in
dichloroanilines have also been discussed by Dou et al. (1993)
˚
˚
´
´
symmetry code: (vi) ꢄx + 2, ꢄy + 1, ꢄz + 1], with an offset C6
˚
interplanar separation of 3.01 A. Two weak C—Hꢀ ꢀ ꢀF
˚
´ ´
and Kalman et al. (1993).
contacts are also present (Hꢀ ꢀ ꢀF = 2.65 A, and C—Hꢀ ꢀ ꢀF = 115
and 117ꢁ).
In (III), the one-dimensional chains are further linked by
C—Hꢀ ꢀ ꢀꢀ(arene) contacts into two-dimensional sheets (Figs. 8
and 9, and Table 6). Molecules are also linked via antiparallel
C
Oꢀ ꢀ ꢀO C interactions (Allen et al., 1998) aligned about
inversion centres, with C1ꢀ ꢀ ꢀO1iii distances of 3.1919 (16) A
˚
[symmetry code: (iii) ꢄx + 2, ꢄy, ꢄz + 1].
Usually benzamides form intermolecular N—Hꢀ ꢀ ꢀO
C
interactions [with a C(4) graph set] as their primary inter-
action in the absence of other competing strong donors/
acceptors (Gowda et al., 2008). In (I)–(III), the amide NH
group and pyridine N-atom acceptor form amide–pyridine
N—Hꢀ ꢀ ꢀN chains [graph set C(6)] as the primary interaction,
thus preventing the formation of standard C(4) chains. In (I),
the closest intermolecular Nꢀ ꢀ ꢀO contact [N1ꢀ ꢀ ꢀO1(x ꢄ 1, y,
ꢁ
˚
˚
z) = 3.438 (2) A along [100]; N—Hꢀ ꢀ ꢀO = 125 ] is 0.4 A longer
and ꢅ20ꢁ smaller in angle than the amide–pyridine N—Hꢀ ꢀ ꢀN
interaction. For (II), the closest intermolecular Nꢀ ꢀ ꢀO contact
˚
[N1ꢀ ꢀ ꢀO1(x ꢄ 1, y, z) = 3.562 (2) A along [100]; N—Hꢀ ꢀ ꢀO =
ꢁ
ꢁ
˚
130 ] is 0.5 A longer and ca 18 smaller in angle than the
amide–pyridine N—Hꢀ ꢀ ꢀN interaction, while in (III) the
Figure 8
The primary N—Hꢀ ꢀ ꢀN interactions in (III); H atoms not involved in
these interactions have been omitted. The asterisk (*) indicates the
1
symmetry-related pyridine ring at (x, y ꢄ , z + 12 ). [Symmetry codes: (i)
2
1
2
1
2
1
2
1
2
ꢄx + 1, y + , ꢄz + ; (ii) ꢄx + 1, y ꢄ , ꢄz + .]
Figure 7
Figure 9
A stereoview of the C—Fꢀ ꢀ ꢀF—C contacts in (II), with atoms depicted as
Two C—Hꢀ ꢀ ꢀꢀ(arene) contacts in (III), with atoms depicted as their van
their van der Waals spheres.
der Waals spheres; the dollar symbols ($) indicate the arene rings.
ꢃ
Acta Cryst. (2008). C64, o335–o340
Donnelly et al. C12H9FN2O o337

organic compounds
The replacement of an F atom on the C6 ring involves
isosteric replacement of an H atom. The change of the F-atom
site from para to meta to ortho only generates different
secondary interactions (as can be reasoned), as primary
amide–pyridine N—Hꢀ ꢀ ꢀN interactions define the principal
aggregation mode. Chopra & Row (2008) have recently
reported a comprehensive study on a series of mono- and
difluorobenzanilides [DC3–DC1, hereafter denoted DC(3–1);
see scheme below]. The DC(3–1) structures correspond to (I)–
(III) by replacement of the pyridine N atom by a CH group.
The DC(3–1) packing is dominated by standard N—
The overall packing is very similar at the primary amide–
pyridine N—Hꢀ ꢀ ꢀN level and reasonably comparable (in
terms of the number and type of weak interactions) at the
secondary level.
An explanation for this melting-point trend may be the
distinct N—Hꢀ ꢀ ꢀO C distance differences of 3.438 (2),
˚
3.562 (2) and 3.7854 (16) A in (I)–(III), resulting from the
molecular packing; the packing may be such as to prevent the
potential (though temporary) formation of amide–amide N—
Hꢀ ꢀ ꢀO C interactions as the amide–pyridine N—Hꢀ ꢀ ꢀN
interactions weaken on heating. In (I), without the steric
demand of an ortho-F atom, the weakening of the amide–
pyridine N—Hꢀ ꢀ ꢀN hydrogen bond may be compensated
for and offset by some increasing but temporary N—
Hꢀ ꢀ ꢀO C interaction, resulting in the observed melting-point
trend.
The present series is unusual as the three isomers are
isomorphous (having similar unit-cell parameters, packing and
alignment), but differ in F/H peripheral atom-site position and
in their interactions and contacts at the secondary level.
˚
Hꢀ ꢀ ꢀO C hydrogen bonds [3.165 (4)–3.254 (4) A], the intra-
molecular C6/C6 plane angles range from 23.0 (3) to 32.9 (1)ꢁ,
˚
and the Nꢀ ꢀ ꢀO distances are at least 0.2 A shorter than the
corresponding data in (I)–(III) (Chopra & Row, 2008). In
these fluorobenzanilides, alteration of the packing modes is
observed as the F-atom position changes through para to meta
to ortho. In related work, Gowda et al. (2008) have also
reported a series of similar substituted alkyl- and chloro-
phenylbenzamides. Wardell et al. (2008) have also recently
reported an extensive series of N-arylpyrazinecarboxamides;
however, the authors state that isomeric compounds in this
series ‘show little resemblance in the supramolecular beha-
viour beyond crystallization in the same space group’. Clearly,
more expanded isomer series are needed for detailed struc-
tural and computational comparisons.
Experimental
Compound (I) has been synthesized previously both as (i) a labelled
[carbonyl-11C]amide via a one-pot in situ reaction of the amine
coupled with [11C]carboxymagnesium halides generated from
Grignard reagents and cyclotron-produced [11C]CO2, and (ii) an
unlabelled amide via microwave-irradiated Grignard coupling reac-
tions (Lu et al., 2003). N-(4-Pyridyl)benzamides have been patented
as potential cardiotonics (Sakakibara et al., 1987).
For the preparation of (I)–(III), typically, 4-/3-/2-fluorobenzoyl
chloride in dry CH2Cl2 (20–30 ml) was added dropwise (over a period
of 2–3 min) to a 20–30 ml solution of 4-aminopyridine containing
Et3N (1.5 ml), and the reaction mixture was stirred overnight. Typical
organic work-up and washing furnished the products in reasonable
yields of 20–40%. Crystals suitable for X-ray diffraction were grown
from CHCl3 as colourless blocks over a period of 1–2 weeks.
For (I), m.p. 456–459 K (uncorrected). IR (ꢁC O, cmꢄ1): 1723 (s),
1
1682 (m) (CHCl3); 1677 (s) (KBr). H NMR (400 MHz, CDCl3): ꢂ
8.47 (d, 2H, 4-pyr), 8.07 (br s, 1H, N—H), 7.84 (m, 2H, 4-Fbenz), 7.54
(d, 2H, 4-pyr), 7.12 (m, 2H, 4-Fbenz). For (II), m.p. 443–446 K
(uncorrected). IR (ꢁC O, cmꢄ1): 1738 (w), 1710 (s) (CHCl3); 1683 (s)
(KBr). 1H NMR (as above): ꢂ 8.60 (d, 2H, 4-pyr), 7.93 (br s, 1H, N—
H), 7.64 (m, 4H, 4-pyr and 3-Fbenz), 7.53 (m, 1H, 3-Fbenz), 7.35 (m,
1H, 3-Fbenz). For (III), m.p. 396–398 K (uncorrected). IR (ꢁC
,
O
cmꢄ1): 1689 (s) (CHCl3); 1685 (s) (KBr). 1H NMR (as above): 8.66 (br
d, 1H, N—H), 8.57 (d, 2H, 4-pyr), 8.17 (t, 1H, 2-FBenz), 7.64 (m, 2H,
4-pyr), 7.59 (m, 1H, 2-Fbenz), 7.36 (t, 1H, 2-Fbenz), 7.22 (t, 1H,
2-Fbenz).
Melting-point analysis and correlations with structural
properties have been reviewed for organic compounds by
several groups recently (Slovokhotov et al., 2004; Gilbert,
2007). Researchers have noted that more symmetrical struc-
tural isomers almost always possess higher melting points than
their less symmetric analogues (Gilbert, 2007). Compounds
(I)–(III) can only possess mirror symmetry (Cs) as the highest
possible molecular symmetry in the appropriate conformation
(solution/gas phase), but for (III) this is unlikely on steric
grounds (N—Hꢀ ꢀ ꢀF steric hindrance). There is a distinct trend
from (I) (456–459 K) to (II) (443–446 K) to (III) (396–398 K).
Isomer (I)
Crystal data
3
˚
C12H9FN2O
Mr = 216.21
V = 988.27 (10) A
Z = 4
Monoclinic, P21=c
Mo Kꢄ radiation
ꢅ = 0.11 mmꢄ1
T = 150 (1) K
0.26 ꢆ 0.14 ꢆ 0.12 mm
˚
a = 5.6506 (3) A
b = 11.3882 (8) A
˚
˚
c = 15.4314 (8) A
ꢃ = 95.602 (3)ꢁ
ꢃ
o338 Donnelly et al. C12H9FN2O
Acta Cryst. (2008). C64, o335–o340

organic compounds
Table 4
Hydrogen-bond geometry (A, ) for (II).
Data collection
ꢁ
˚
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
7401 measured reflections
2246 independent reflections
1465 reflections with I > 2ꢆ(I)
Rint = 0.052
Cg1 and Cg2 are the centroids of the C11–C16 and C21–C23/N24/C25/C26
rings.
Tmin = 0.893, Tmax = 0.988
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
N1—H1ꢀ ꢀ ꢀN24i
0.847 (19)
0.95
0.95
0.95
0.95
2.30 (2)
2.31
2.78
2.88
2.83
3.049 (2)
2.884 (2)
3.4407 (18)
3.808 (2)
3.505 (2)
147.6 (16)
118
128
165
129
Refinement
C26—H26ꢀ ꢀ ꢀO1
C26—H26ꢀ ꢀ ꢀCg1ii
C14—H14ꢀ ꢀ ꢀCg2iii
C15—H15ꢀ ꢀ ꢀCg2iv
R[F2 > 2ꢆ(F2)] = 0.051
wR(F2) = 0.147
S = 1.03
2246 reflections
149 parameters
H atoms treated by a mixture of
independent and constrained
refinement
ꢄ3
˚
Áꢇmax = 0.28 e A
1
2
1
2
1
1
Symmetry codes: (i) ꢄx þ 1; y þ ; ꢄz þ ; (ii) ꢄx þ 2; ꢄy; ꢄz þ 1; (iii) x; ꢄy ꢄ ; z ꢄ ;
2
2
ꢄ3
˚
(iv) ꢄx þ 1; ꢄy; ꢄz þ 1.
Áꢇmin = ꢄ0.31 e A
Table 1
Isomer (III)
Selected torsion angles (ꢁ) for (I).
Crystal data
O1—C1—N1—C21
O1—C1—C11—C12
2.5 (3)
32.0 (2)
C11—C1—N1—C21
C1—N1—C21—C26
ꢄ178.28 (16)
3
˚
V = 989.80 (8) A
Z = 4
C12H9FN2O
Mr = 216.21
17.7 (3)
Monoclinic, P21=c
Mo Kꢄ radiation
ꢅ = 0.11 mmꢄ1
T = 150 (2) K
0.35 ꢆ 0.30 ꢆ 0.18 mm
˚
a = 5.9832 (3) A
b = 11.1508 (5) A
˚
Table 2
Hydrogen-bond geometry (A, ) for (I).
ꢁ
˚
˚
c = 14.8921 (7) A
ꢃ = 94.986 (3)ꢁ
Cg1 is the centroid of the C11–C16 ring.
Data collection
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
6092 measured reflections
2252 independent reflections
1744 reflections with I > 2ꢆ(I)
Rint = 0.031
N1—H1ꢀ ꢀ ꢀN24i
C26—H26ꢀ ꢀ ꢀO1
C26—H26ꢀ ꢀ ꢀCg1ii
0.84 (2)
0.95
0.95
2.29 (2)
2.32
2.71
3.022 (2)
2.878 (2)
3.373 (2)
146 (2)
117
128
Tmin = 0.911, Tmax = 0.982
1
2
1
2
Symmetry codes: (i) ꢄx þ 1; y þ ; ꢄz þ ; (ii) ꢄx þ 2; ꢄy; ꢄz þ 1.
Refinement
R[F2 > 2ꢆ(F2)] = 0.044
wR(F2) = 0.121
S = 1.04
2252 reflections
149 parameters
H atoms treated by a mixture of
independent and constrained
refinement
Isomer (II)
ꢄ3
˚
Áꢇmax = 0.18 e A
ꢄ3
Crystal data
˚
Áꢇmin = ꢄ0.24 e A
3
˚
V = 978.45 (8) A
Z = 4
C12H9FN2O
Mr = 216.21
Table 5
Monoclinic, P21=c
Mo Kꢄ radiation
ꢅ = 0.11 mmꢄ1
T = 150 (2) K
0.32 ꢆ 0.20 ꢆ 0.12 mm
Selected torsion angles (ꢁ) for (III).
˚
a = 5.7537 (3) A
˚
b = 11.2421 (4) A
˚
c = 15.1672 (7) A
O1—C1—N1—C21
O1—C1—C11—C12
6.1 (2)
ꢄ147.55 (14)
C11—C1—N1—C21
C1—N1—C21—C26
ꢄ176.77 (12)
ꢃ = 94.188 (2)ꢁ
11.2 (2)
Data collection
Table 6
Hydrogen-bond geometry (A, ) for (III).
ꢁ
˚
Nonius KappaCCD diffractometer
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
8753 measured reflections
2236 independent reflections
1474 reflections with I > 2ꢆ(I)
Rint = 0.054
Cg1 and Cg2 are the centroids of the C11–C16 and C21–C23/N24/C25/C26
rings.
Tmin = 0.801, Tmax = 0.989
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
Refinement
N1—H1ꢀ ꢀ ꢀN24i
0.844 (19)
0.844 (19)
0.95
0.95
0.95
2.333 (18)
2.342 (17)
2.30
2.83
2.93
3.0213 (17)
2.7544 (15)
2.8681 (17)
3.4549 (13)
3.7693 (17)
139.1 (15)
110.6 (14)
118
124
149
R[F2 > 2ꢆ(F2)] = 0.048
wR(F2) = 0.132
S = 1.06
2236 reflections
150 parameters
H atoms treated by a mixture of
independent and constrained
refinement
N1—H1ꢀ ꢀ ꢀF12
C26—H26ꢀ ꢀ ꢀO1
C26—H26ꢀ ꢀ ꢀCg1ii
C14—H14ꢀ ꢀ ꢀCg2iii
ꢄ3
˚
Áꢇmax = 0.26 e A
ꢄ3
˚
Áꢇmin = ꢄ0.28 e A
1
2
1
2
1
2
Symmetry codes: (i) ꢄx þ 1; y þ ; ꢄz þ ; (ii) ꢄx þ 2; ꢄy; ꢄz þ 1; (iii) x; ꢄy ꢄ ,
1
z ꢄ .
2
Table 3
H atoms attached to C atoms were treated as riding using the
Selected torsion angles (ꢁ) for (II).
˚
SHELXL97 (Sheldrick, 2008) defaults at 150 (1) K [C—H = 0.95 A
and Uiso(H) = 1.2Ueq(C)]; N-bound H atoms were refined freely with
˚
isotropic displacement parameters to bond lengths of 0.84 (2) A in
O1—C1—N1—C21
O1—C1—C11—C12
5.4 (3)
31.8 (2)
C11—C1—N1—C21
C1—N1—C21—C26
ꢄ175.38 (15)
13.8 (3)
˚
(I), 0.847 (19) A in (II) and 0.844 (19) A in (III).
˚
ꢃ
Acta Cryst. (2008). C64, o335–o340
Donnelly et al. C12H9FN2O o339

organic compounds
Eijck, B. P., Erk, P., Facelli, J. C., Bazterra, V. E., Ferraro, M. B., Hofmann,
D. W. M. et al. (2005). Acta Cryst. B61, 511–527.
Dou, S., Weiden, N. & Weiss, A. (1993). Acta Chim. Acad. Sci. Hung. 130, 497–
522.
Ferguson, G. (1998). PREP8. University of Guelph, Canada.
Gelbrich, T., Hursthouse, M. B. & Threlfall, T. L. (2007). Acta Cryst. B63, 621–
632.
Gilbert, A. S. (2007). Thermochim. Acta, 452, 135–139.
ˇ´ ˇ´ˇ
Gowda, B. T., Tokarcık, M., Kozısek, J. & Sowmya, B. P. (2008). Acta Cryst.
E64, o83.
For all isomers, data collection: KappaCCD Server Software
(Nonius, 1997); cell refinement: DENZO–SMN (Otwinowski &
Minor, 1997); data reduction: DENZO–SMN; program(s) used to
solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to
refine structure: SHELXL97 (Sheldrick, 2008) and SORTX
(McArdle, 1995); molecular graphics: PLATON (Spek, 2003); soft-
ware used to prepare material for publication: SHELXL97 and
PREP8 (Ferguson, 1998).
´
´
´
´
Kalman, A., Parkanyi, L. & Argay, G. (1993). Acta Cryst. B49, 1039–1049.
Lu, S.-Y., Hong, J. & Pike, V. W. (2003). J. Labelled Compd Radiopharm. 46,
1249–1259.
JFG thanks Dublin City University for funds in aid of
undergraduate research and Mr Damien McGuirk for
providing excellent technical and laboratory assistance.
McArdle, P. (1995). J. Appl. Cryst. 28, 65.
Nonius (1997). KappaCCD Server Software. Windows 3.11 Version. Nonius
BV, Delft, The Netherlands.
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276,
Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M.
Sweet, pp. 307–326. New York: Academic Press.
Sakakibara, K., Yoneshima, N. & Osawa, T. (1987). Jpn Kokai Tokkyo Koho,
CODEN JKXXAF JP 62158252 A 19870714 Showa (patent written in
Japanese).
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SK3227). Services for accessing these data are
described at the back of the journal.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
References
Slovokhotov, Y. L., Neretin, A. S. & Howard, J. A. K. (2004). New J. Chem. 28,
967–979.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.
Wardell, S. M. S. V., de Souza, M. V. N., Vasconcelos, T. R. A., Ferreira, M. L.,
Wardell, J. L., Low, J. N. & Glidewell, C. (2008). Acta Cryst. B64, 84–100.
Wardell, S. M. S. V., de Souza, M. V. N., Wardell, J. L., Low, J. N. & Glidewell,
C. (2007). Acta Cryst. B63, 879–895.
Allen, F. H., Baalham, C. A., Lommerse, J. P. M. & Raithby, P. R. (1998). Acta
Cryst. B54, 320–329.
Blessing, R. H. (1995). Acta Cryst. A51, 33–38.
Chopra, D. & Guru Row, T. N. (2008). CrystEngComm, 10, 54–67.
Day, G. M., Motherwell, W. D. S., Ammon, H. L., Boerrigter, S. X. M., Della
Valle, R. G., Venuti, E., Dzyabchenko, A., Dunitz, J. D., Schweizer, B., van
ꢃ
o340 Donnelly et al. C12H9FN2O
Acta Cryst. (2008). C64, o335–o340