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Table 1 (continued)
(V)
(VI)
(VII)
(VIII)
No. of restraints
H-atom treatment
1
12
12
0
H-atom parameters
constrained
H-atom parameters
constrained
–0 .18, ꢂ0.26
H-atom parameters
constrained
–0 .33, ꢂ0.23
H-atom parameters
constrained
–0 .18, ꢂ0.15
˚
ꢂ3
)
Áꢈmax, Áꢈmin (e A
Absolute structure
0.11, ꢂ0.14
Flack x determined using
7
72 quotients
+
ꢂ
+
ꢂ
[
(I ) ꢂ (I )]/[(I ) + (I )]
Parsons et al., 2013)
0.1 (5)
(
Absolute structure para-
meter
–
–
–
Computer programs: APEX2 (Bruker, 2004), CrysAlis PRO (Agilent, 2012), X-AREA (Stoe & Cie, 2002), SAINT (Bruker, 2004), CrysAlis RED (Agilent, 2012), X-RED (Stoe & Cie,
002), SHELXS97 (Sheldrick, 2008), SUPERFLIP (Palatinus & Chapuis, 2007), SHELXL2014 (Sheldrick, 2015) and PLATON (Spek, 2009).
2
a solution of sulfisoxazole (100 mg, 0.374 mmol) in ethanol
sets of atomic sites having unequal occupancies. For the minor-
disorder component, the bonded distances and the 1,3
nonbonded distances were restrained to be the same as the
corresponding distances in the major component, subject to
(
(
15 ml) was added to a solution of either salicylaldehyde
45 mg, 0.374 mmol) for (I) or 5-bromo-2-hydroxy-3-methoxy-
benzaldehyde (86 mg, 0.374 mmol) for (II), each in ethanol
5 ml) in the presence of a catalytic quantity of glacial acetic
˚
(
s.u. values of 0.005 and 0.01 A, respectively; in addition, the
acid. These solutions were heated under reflux for 4 h, when
thin-layer chromatography (TLC) confirmed that the reac-
tions were complete. The solutions were cooled to ambient
temperature and the resulting solid products were collected by
filtration, dried in air and then recrystallized from ethanol for
anisotropic displacement parameters for corresponding pairs
of partially occupied sites were constrained to be identical. An
entirely similar procedure was adopted for the disorder in
compound (VII). All H atoms, apart from those in the disor-
dered parts of compounds (VI) and (VII), were located in
difference maps. All H atoms, other than those bonded to the
pyramidal atoms N4 in compounds (I) and (II), were treated
as riding atoms in geometrically idealized positions, with O—
(
I) or from dimethyl sulfoxide for (II), giving crystals suitable
for single-crystal X-ray diffraction [m.p. 435–439 K for (I) and
43–448 K for (II)]. For the syntheses of compounds (III) and
IV), to a solution of either 2-aminophenol (100 mg, 0.917 mmol)
4
(
˚ ˚
H = 0.82 A [0.84 A in (VII)] and U (H) = 1.5U (O), N—H =
iso eq
˚
0.86 A and U (H) = 1.2U (N), and C—H = 0.93 (alkenyl and
iso eq
for (III) or 2-methoxyaniline (100 mg, 0.813 mmol) for (IV) in
ethanol (20 ml), an equimolar amount of 5-bromo-2-hydroxy-
aromatic), 0.95 [alkenyl and aromatic in compound (VII)
˚
only], 0.96 (CH ), 0.97 (CH ) or 0.99 A [CH in compound
3-methoxybenzaldehyde [211 mg, 0.917 mmol for (III) and
04 mg, 0.813 mmol for (IV)] was added dropwise with
3
2
2
2
(VII) only], and with U (H) = kU (C), where k = 1.5 for the
iso
eq
constant stirring, in the presence of a catalytic amount of
glacial acetic acid. Each mixture was heated under reflux for
methyl groups, which were permitted to rotate but not to tilt,
and 1.2 for all other H atoms bonded to C atoms. The H atoms
in the disordered parts of compounds (VI) and (VII) were
4
h, after which the reactions were judged from TLC to be
˚
complete. The mixtures were cooled to ambient temperature
and the resulting solid products were collected by filtration
and then recrystallized from dimethyl sulfoxide for (III) and
from N,N-dimethylformamide for (IV), providing crystals
suitable for single-crystal X-ray diffraction [m.p. 480–485 K
for (III) and 347–350 K for (IV)]. The preparations of
compounds (V), (VII) and (VIII) have been described
previously (Chattopadhyay et al., 2009; Kaur et al., 2014; Tunc¸
et al., 2009); compound (VI) was prepared exactly as for (VII)
included in calculated positions, with C—H = 0.97 A in (VI)
˚
and 0.99 A in (VII), and with U (H) = 1.2U (C), giving
iso
eq
refined occupancies of 0.705 (4) and 0.295 (4) in (VI), and
0.851 (3) and 0.149 (3) in (VII). For H atoms bonded to N4 in
each of (I) and (II), the atomic coordinates were refined with
U (H) = 1.2U (N), giving the N—H distances shown in
Table 4. In the absence of significant resonant scattering for
compound (V), it was not possible to determine the correct
orientation of the structure relative to the polar-axis direction:
the Flack x parameter (Flack, 1983), as calculated using 772
iso
eq
(Kaur et al., 2014), except that 5-fluorosalicylaldehyde was
+
ꢂ
+
ꢂ
used in place of unsubstituted salicylaldehyde, and crystal-
lization was from acetonitrile rather than from the dichloro-
methane used for (VII) [m.p. 413–418 K for (VI)].
quotients of the type [(I ) ꢂ (I )]/[(I ) + (I )] (Parsons et al.,
2013), was 0.1 (5). For several of the refinements, the final
analyses of variance showed unexpected values of K =
2
2
[mean(F )/mean(F )] for the groups of the very weakest
o c
reflections having low values of F /F (max); thus, for (III) and
2.2. Refinement
c
c
Crystal data, data collection and structure refinement
(IV), respectively, ꢂ1.707 and ꢂ1.697 for 308 and 336 reflec-
tions in the F /F (max) ranges 0.000–0.008 and 0.000–0.007; for
(V), 0.904 for 280 reflections in the F /F (max) range 0.000–
details are summarized in Table 1. Several low-angle reflec-
tions which had been attenuated by the beam stop were
omitted from the final refinements; thus, reflection 100 for
each of (I)–(III), 001 for (IV) and 200 for (V). It was apparent
from an early stage in the refinement of compound (VI) that
the atoms in the –(CH ) – portion were disordered over two
c
c
c
c
0.009; and for (VIII), 7.612 for 549 reflections in the Fc/
Fc(max) range 0.000–0.007 and 2.022 for 445 reflections in the
F /F (max) range 0.007–0.014; these values are probably
c
c
statistical artefacts.
2
4
ꢀ
4
of 11 Girisha et al. Eight Schiff bases derived from various salicylaldehydes
Acta Cryst. (2018). C74
Girisha, Marisiddaiah
